final exam

Question 1

Nutrients

Answer 1

Diet = total food a person regularly eats
Our diet determines which nutrients we consume
Nutrients = food substances required for our maintenance, growth and survival
Some nutrients are essential
Essential nutrient = one that the body requires but that it cannot make itself
Ex. Essential amino acids, essential fatty acids, vitamins, minerals, water
There are six categories of nutrients…

Question 2

The Macronutrients

Answer 2

(needed in larger amounts)
Water

Carbohydrates
Sugars, starches, fibre
Organic (carbon-containing)

Lipids (fats)
Triglycerides, fatty acids, sterols, phospholipids
Organic

Proteins
Made of amino acids
Organic

Question 3

The Micronutrients

Answer 3

needed in smaller amounts
Vitamins
-Fat soluble and water soluble
-Organic

Minerals

• Chemical elements
• inorganic

Question 4

Phytochemicals

Answer 4

Phytochemicals = plant chemicals
Hundreds of them
Found in a wide variety of plants
Responsible for their bright colours 
May have positive health effects

ex. Flavonoids – give plants bright blue, red or dark pigmentation
Anti-inflammatory, anti-tumour, antioxidant effects

Carotenoids – give plants yellow, orange, red pigmentation
Antioxidant effects

Question 5

Toxins

Answer 5

Naturally occurring substances found in plants and animals
Can have harmful effects on body beyond a threshold of intake
Their levels are limited in foods
To reduce exposure throw out old/mouldy/foul-smelling food

Question 6

Fortification of food

Answer 6

Fortified aka enriched foods - involves the addition of nutrients to foods by the food manufacturer

Can be
mandatory ex. iodine to table salt
voluntary ex. Added vitamins to breakfast cereals

Question 7

Whole foods vs. Processed foods

Answer 7

Most foods have some degree of processing
Whole foods = least amount of processing, associated with reduced disease risk
Ultra-processed foods = higher risk of type 2 diabetes, cardiovascular disease, mortality
Can use NOVA classification system to differentiate foods for degree of processing

Question 8

4 NOVA food groups

Answer 8

NOVA Group 1: Unprocessed or Minimally Processed Foods
NOVA Group 2: Processed Culinary Ingredients
NOVA Group 3: Processed Foods
NOVA Group 4: Ultra-processed foods

Question 9

Food Additives

Answer 9

Substances added to food to affect taste, appearance, safety, freshness etc.
Must first be approved through an evidence review
There amounts are controlled in foods
More common in processed, ultra-processed foods

Question 10

Genetically Modified Food

Answer 10

GMFs = foods that have undergone alterations to their DNA
DNA can be altered through
Selective breeding ex. Seedless grapes, broccoflower
Use of a vector: ex. Golden rice, RoundUp Ready Soy

Do not change our DNA
“GM foods currently available on the international market have passed safety assessments and are not likely to present risks for human health” (World Health Organization, 2014)
Concerns/debates remain around biodiversity, allergic potential, ethics, labelling

Question 11

why do we eat

Answer 11

Sustenance: the maintenance of our bodies and lives
Nutrients contribute to
Body structure
Body function
Energy provision
Carbs, proteins = 4 kcal/g
Lipids = 9 kcal/g
Enjoyment
Psychological Reasons

Question 12

Gene-Diet Interactions

Answer 12

Genetics can influence nutrition in a number of ways
Ex. Genetic influences on appetite, nutrient absorption, nutrient use

Our diet can also influence the expression of genes (ie. Whether gene information leads to the formation of proteins)
=epigenetics
NOTE: diet does not change our DNA/genes!

Question 13

Choosing a Healthy Diet

Answer 13

Balance = consuming nutrients and energy in the proportions that most promote health
Variety = consuming a diversity of foods
We are less likely to be deficient in nutrients if we consume a range of different whole foods.
Moderation = not too much, not too little
Nutrient density = amount of nutrients in a food/meal compared to a reference amount (ex. 100 kcal)

Question 14

The Study of Nutrition

Answer 14

It is difficult to study nutrition for a number of reasons:
People change their diet constantly
We can’t force people to eat a certain way
It is difficult to know for certain what people eat
Other factors beyond nutrition also affect health
Difficult to establish causation
…..
The scientific method is used to study nutrition
Experiments and epidemiological research are the most common types of nutrition studies
Both use the scientific method

Question 15

experimental Studies

Answer 15

randomized control trials
Usually involves two similar groups
Experimental group – undergoes the experimental treatment (ex. Dietary supplement)
Control group – does not undergo the experimental treatment; may use a placebo (ex. Sugar pill)

Only one factor is different between the two groups (ex. Experimental group received the supplement)
if there is a difference in the groups by the end (ex. Increase in perceived alertness in experimental group), it is most likely due to the factor being tested

Question 16

Epidemiological Studies

Answer 16

Aka population-based studies: look at population trends without manipulating variables
Ex. Do Japanese people who eat a lot of fish have a lower risk of cardiovascular disease than Americans who do not eat a lot of fish?
Ex. Nurses’ Health Study:
gathered information about nurses habits, medical history etc.
Checked in on them over time
Questions: what factors increased risk of cardiovascular disease, cancer etc.?
Limitations of Epidemiology
Association does not equal causation!
Results could be for other reasons too
People change their diet over time

Also, our methods of determining people’s diet all have limitations…
Impossible to for sure know what and how much people eat

Question 17

Evaluating Nutrition Sources

Answer 17

VETO
is it valuable
is it eviendence based
is it trustworthy
is it opinion based

Question 18

Nutritional Status

Answer 18

= condition of the body with respect to nutrition
i.e. Does a person have the appropriate level of nutrients to meet their needs?
No perfect measure, but we may use:
Diet analyses
Laboratory tests
Health or disease state of individual

Question 19

The Four DRIs

Answer 19

Estimated Average Requirement(EAR):
the intake level which meets the needs of 50% of the population. (The RDA is determined by first determining the EAR)

Recommended Dietary Allowance (RDA):
consumption of this amount of the nutrient meets the needs of 97% of the population (set 2 standard deviations above the EAR)

Adequate Intake (AI): 
Nutrient intakes that are used as a goal when evidence is insufficient to set an RDA. AI values approximate the amount of nutrient that sustains health

Tolerable Upper Limit (TUL/UL):
The highest amount of that nutrient that will not promote symptoms of toxicity in the majority of healthy individuals. Intake should not exceed this value

Question 20

Estimated Energy Requirement

Answer 20

EER = amount of energy required to maintain current energy state (ie. Where fat mass and weight do not change substantially)
Depends on sex, age, weight, height and activity level (PA)

Question 21

Acceptable Macronutrient Distribution Range

Answer 21

AMDR = recommended percentage of energy that should come from each of the three energy-yielding nutrients: carbohydrates, lipids and protein

Question 22

First Nations Healthy Food Guidelines

Answer 22

Make the community healthier by working together to change the nutrition environment.
Increase the use of traditional foods by protecting, restoring and relying on them more.
Decrease the use of sugar-sweetened beverages to help protect teeth and children’s health.
Increase the intake of vegetables and fruits.
Serve healthier foods in reasonable portions.
Increase number of community gardens to both provide nutritious food and bring the community together

Question 23

Canada’s Healthy Eating Strategy

Answer 23

= overhaul of Canadian food policy that began in 2013
Major changes
2019 Canadian food guide
Lowered sodium content in prepackaged foods
Reasonable sodium targets within food and hospitality industries
Expansion of vitamin D fortification program
Elimination of industrial trans fat from food supply
Changes to food labelling

Mandatory Features of Canadian Food Labels

Question 24

Claims on Food Labels

Answer 24

Food packaging may contain certain claims to highlight a nutrient, health-associated factor or the nature of a food
There are different types of claims
Claims must meet standards set by Food and Drug Regulations

Question 25

Nutrient Content Claims

Answer 25

Ex. Low in fat, lower in Calories, high in fibre To be used, the product must comply with the requirements for that statement Ex. High in fibre = 4+ grams per serving very high in fibre = 6+ grams per serving

Question 26

Health Claims

Answer 26

Two main types Disease-reduction claims link a food or its ingredients with a reduced risk of developing a specific disease Ex. A healthy diet with adequate calcium and vitamin D and regular physical acivity helps to reduce risk of osteoporosis Function claims note the association between consuming a nutrient or diet factor with its role in the normal biological function of the body Ex. Calcium promotes strong bones and teeth

Question 27

Natural Health Products (NHPs)

Answer 27

NHPs are neither foods nor drugs. They are naturally occurring substances that may be used to address health needs Ex. Items sold as vitamins, minerals, multivitamins, probiotics, amino acids and essential fatty acids, as well as homeopathic and traditional medicines Regulated separately by the Natural and Nonprescription Health Products Directorate (NNHPD) Review claims and available evidence before approving product for sale

Question 28

Menu Labelling

Answer 28

There are no federal requirements in Canada for menu labelling Ontario’s Healthy Menu Choice act is a mandatory program for restaurants with more than 20 locations Must display: Calories Contextual statement: “Adults and youth (ages 13 and older) need an average of 2,000 calories a day, and children (ages 4 to 12) need an average of 1,500 calories a day. However, individual needs vary.” The Informed Dining Program is a voluntary program where consumers have access to nutritional information by request

Question 29

Digestion

Answer 29

Digestion separates the nutrients in food and breaks larger molecules into smaller ones so they can be absorbed Polysaccharides → sugars Triglycerides → fatty acids Proteins → amino acids Two types of digestion: Mechanical/physical: uses physical process such as chewing to break food apart Chemical digestion: uses enzymes to alter the chemical structure of nutrients

Question 30

Enzymes

Answer 30

Enzymes speed up the rate of reaction Provide a location for chemical reactions to occur Enzymes can participate in hydrolysis and condensation reactions Hydrolysis reaction: the input of water helps to break down the molecule:

Question 31

Condensation reactions

Answer 31

the process of co sensation binds molecules such as amino acids, into larger chains of molecules. water is liberated in the process the binding of amino acids into a specific chain begins the process of protein synthesis.

Question 32

Hormones

Answer 32

Hormones are chemical messengers that are required for many physiological processes, including digestion They are released form one area of the body and travel through the blood to different parts of the body

Question 33

The Digestive Tract

Answer 33

Long, tube-like structure Sphincters often separate different parts of the tube Takes ~ 2+ days for material to pass through the entire tract Food spends most time in the large intestine

Question 34

The Mouth

Answer 34

Teeth rip food apart Tongue pushes food towards teeth and mixes it with saliva Salivary glands secrete saliva into mouth, which contains: Salivary amylase digests amylose (starch) Lingual lipase digests lipids Mucus lubricates food Lysozyme = antibacterial substance that disinfects food When food leaves the mouth it is a bolus

Question 35

The Pharynx

Answer 35

Aka throat Common passageway for food and inspired air No active digestion or absorption The epiglottis directs food from the pharynx into the esophagus instead of down the wrong tube into the trachea (windpipe)

Question 36

The Esophagus

Answer 36

No active digestion or absorption | Peristalsis is a type of movement that occurs here and in other parts of the tract

Question 37

The Stomach

Answer 37

Temporary reservoir for food Food remains here 4-5 hours Three layers of muscles allow stomach to churn Lower esophageal sphincter and pyloric sphincter close as stomach churns food and mixes it with gastric juice When food leaves the stomach it is in a semi-liquid form = chyme

Question 38

Gastric Juice

Answer 38

``` Cells in the stomach crypts secrete contents of gastric juice: Mucus Lubrication, medium for chemical reactions Gastric lipase Breaks down lipids Hydrochloric acid Unravels proteins, activates pepsinogen Pepsinogen Becomes pepsin, which digests protein ```

Question 39

The Small Intestine

Answer 39

Primary site of digestion and absorption Three sections: duodenum, jejunum, ileum Long length (~6m), large circular folds, villi, microvilli contribute to its large surface area Its total surface area is about the size of a tennis court!

Question 40

Villi of the Small Intestine

Answer 40

``` The villus (plural = villi) is the main functional unit of the small intestine Villi are invaginations of the small intestine wall The cells on their surface have extensions called microvilli (collectively known as the brush border) which secrete enzymes Nutrient subunits are absorbed into the center of the villus where they then enter the blood or the lymph ```

Question 41

The Pancreas

Answer 41

``` The pancreas secretes pancreatic juice into the small intestine =its exocrine function Pancreatic juice contains: Digestive enzymes Amylase, lipase, proteases Bicarbonate Neutralizes chyme ```

Question 42

The Liver, Gallbladder and Bile

Answer 42

The liver makes bile; the gallbladder stores it. Bile is a lipid emulsifier – it breaks larger lipid globules into smaller ones and allows them to be suspended in a watery environment

Question 43

The Large Intestine

Answer 43

``` Approx 1.5 m in length The colon is the main part of the large intestine Here, any unabsorbed material is either: Packaged for removal Acted upon by bacteria = Microbiota ```

Question 44

The Microbiome

Answer 44

The largest population of non-human cells is found in the large intestine Microbiota = all the non-human organisms found in our body Mostly bacteria 300-500 different species Microbiome = the genetic material of the non-human organisms found in our body The microbiota have roles in: Vitamin synthesis (vitamin K, B2, B12) Energy harvesting Health/disease Appetite

Question 45

Probiotics and Prebiotics

Answer 45

Probiotics = cultures of living organisms (ex. Bacteria) Found in yogurt, kombucha Cannot treat or cure any disease, but may help in the management of certain conditions Prebiotics = carbohydrates that act as food for the microbiota Found in asparagus, garlic, banana… Support the health of the microbiome

Question 46

Ulcers

Answer 46

= weakened, damaged parts of the lining of the digestive tract Ex. Canker sores occur in mouth; resolve on own Ex. Peptic Ulcers Occur in esophagus, stomach, small intestine Typically related to infection with H. pylori bacteria

Question 47

Gastroesophageal Reflux Disease

Answer 47

Gastroesophageal reflux = when lower esophageal sphincter weakens; acidic stomach contents spill into esophagus Aka “heart burn” Can lead to gastroesophageal reflux disease (GERD) Can then lead to ulcers, Barrett’s esophagus

Question 48

Irritable Bowel Syndrome(IBS

Answer 48

Cause unknown Symptoms of IBS include abdominal pain, bloating, cramping, diarrhea, constipation, flatulence Treatment focuses on alleviating symptoms: Avoiding trigger foods, managing stress, drinking plenty of fluids…

Question 49

Diverticulitis

Answer 49

Diverticula = weakened walls of the large intestine form outpouchings Diverticula can become inflamed = diverticulitis Diverticula can blead = diverticulosis Age, obesity, smoking, physical inactivity increase risk Diets low in fibre and high in animal fat increase risk

Question 50

Gallstones

Answer 50

Hardened bile deposits that form stones in the gallbladder Can be painful, especially when fat is consumed and gallbladder contracts to release bile Diets high in simple sugars, saturated fat and energy increase risk Gallbladder may need to be removed

Question 51

Digestive Tract Cancers

Answer 51

Cancer = uncontrolled multiplication of our cells Can occur anywhere in digestive tract; most common in colon Colorectal cancer has both genetic and lifestyle risk factors Physical inactivity, obesity increase risk Diets high in red and processed meats increase risk, those high in vegetables, fruits and fibre decrease risk

Question 52

Constipation + Diarrhea

Answer 52

= bowel movements that are difficult to pass or less frequent Stools tend to be dry, hard and can be painful to excrete Increases risk for hemorrhoids Risk factors include age, female sex, genetics, physical inactivity, the use of certain medications and IBS Diet low in fruits, vegetables and water also increases risk Occurs when matter passes too quickly through the large intestine Stools are loose and have a liquid-like consistency Typically due to bacterial and viral infections. Can be caused by food poisoning

Question 53

Delivery of Nutrients to the Liver

Answer 53

Nutrients that enter the blood capillaries at the villi will then enter veins that lead to the liver = All nutrients except large lipids and fat-soluble vitamins At the liver, material is stored, used, detoxified or sent off to the rest of the system The material that enters the cardiovascular system can then be transported to where it is needed

Question 54

Dietary Toxins and Detoxification

Answer 54

Recall that toxins are substances that can be found in food that can cause damage to the body. Ex. Persistent organic pollutants (POPs) Levels of toxins in a well-balanced diet are typically below the threshold for harm Also, the liver, kidneys and lungs remove toxins form the body Lack of evidence to support the use of commercial detox diets for detoxification/ improved health

Question 55

Metabolism

Answer 55

Metabolism = sum of chemical reactions that occur in our bodies Anabolism smaller molecules come together to form larger ones requires an input of energy Catabolism Larger molecules are broken down into smaller ones Leads to a net release of energy The catabolism of the energy-yielding nutrients (carbs, fats, proteins) leads to the release of energy This energy is captured within ATP: the energy currency of the body

Question 56

Cellular Respiration

Answer 56

Cellular respiration = the catabolism of the energy-yielding nutrients leading to the production of ATP Primarily occurs in the mitochondria (“powerhouse”) of the cell It occurs in several steps, collectively known as a metabolic pathway The cellular respiration of glucose is summarized by the equation: Once this is understood, the metabolism of triglycerides and amino acids can be understood

Question 57

Glucose Metabolism

Answer 57

Step 1: Glycolysis Glycolysis = breakdown of glucose Anaerobic; produces minimal ATP Step 2: The Breakdown of Pyruvate Pyruvate catabolism depends on whether oxygen is present (aerobic conditions) or not (anaerobic conditions) Aerobic conditions – acetyl CoA is formed Anerobic conditions- pyruvate is formed Some ATP is formed Cannot be sustained Reversible back to pyruvate when oxygen is again available Step 3: Citric Acid Cycle Citric Acid Cycle= complex set of reactions that begins when acetyl CoA combines with oxaloacetate Produces CO2 , water, and the capture of energy in GTP (≈ATP) Most notably, electron transporters (NADH + H+, FADH2) capture electrons and move to the mitochondrial membrane to begin the electron transport chain Step 4: The Electron Transport Chain Electrons are exchanged between the electron transporters (NADH + H+, FADH2) and membrane-bound proteins This leads to a build up of protons (H+) on one side of the membrane These protons will move through a protein pump that is associated with an enzyme called ATP synthase. This process leads to the production of more than 30 molecules of ATP.

Question 58

Lipid Metabolism

Answer 58

Triglycerides have three fatty acids attached to a glycerol backbone Majority of energy is derived from fatty acids Beta-oxidation splits the fatty acid two carbon atoms at a time Each two-carbon molecule of a fatty acid can be used to form acetyl CoA Proceeds through remaining stages of cellular respiration

Question 59

Ketogenesis

Answer 59

Can occur when diet is high in fat and very low in carbohydrates The citric acid cycle requires carbohydrates On a very low carb diet, fatty acids cannot enter citric acid cycle, instead form ketones

Question 60

Amino Acid Metabolism

Answer 60

First, the nitrogen group of the amino acid must be removed (deaminated) There are 21 amino acids – each with a unique side chain Therefore there are 21 possibilities for what remains Deaminated amino acids will either be used to form: Pyruvate Acetyl CoA Citric Acid Cycle Intermediates

Question 61

Structure and Properties of Water

Answer 61

Water is a polar molecule Other polar molecules are attracted to water = hydrophilic Nonpolar molecules are not attracted to water Water helps structures maintain their form Ex. Cells, humour of eye, synovial sacs…

Question 62

Water Content of the Human Body

Answer 62

``` Human body is 60-70% water by weight 2/3 found within cells = intracellular water 1/3 found outside of cells (ie. In blood, spaces between cells…) = extracellular water ```

Question 63

Movement of water

Answer 63

Osmosis is the movement of water towards charged particles This is done in an effort to even out concentration differences Blood pressure involves a force that pushes water out of blood and into the extracellular space

Question 64

Hydrolysis

Answer 64

Hydrolysis reactions use water to split larger molecules into smaller ones

Question 65

water functions

Answer 65

defense from infections: Water provides an environment for immune cells to fight off infection Water is the main component of mucus, which helps remove infectious agents protection from injuries: Water in synovial fluid protects joints Mucus lines various structures and protects them from physical injuries Water around brain and spinal cord helps protect them from various forces Temperature Regulation: Body temperature is strictly controlled Body uses water to regulate body temperature through two main mechanisms When sweat evaporates, it cools down our body Blood is shunted to the skin’s surface to help promote sweating, lower internal temp

Question 66

Maintaining Water Balance

Answer 66

A main priority of the body is maintaining water homeostasis Since we don’t store water, and we lose it everyday, the emphasis is on preserving body water levels through two main mechanisms: Thirst response Kidneys

Question 67

Dehydration

Answer 67

Either due to insufficient consumption or excessive loss Symptoms include thirst, dry mouth, fatigue, dizziness, irritability, dark urine Chronic dehydration can lead to kidney damage, seizures, hypovolemic shock

Question 68

Water Intoxication

Answer 68

AKA water poisoning When water levels decrease the concentration of dissolved particles in the blood Ex. hyponatremia Potentially fatal Symptoms include headache, confusion, personality changes, irritability, drowsiness Typically due to excessive sweating that is replaced by water alone

Question 69

Diuretics

Answer 69

Substances that promote water loss through urination Ex. Diuretic pills, aka water pills, promote sodium excretion at the kidney, which also promotes water excretion Alcohol and caffeine are also diuretics They are not nutrients, they are psychoactive drugs

Question 70

Caffeine

Answer 70

Compound naturally found in certain seeds, nuts, leaves A diuretic, but mainly used for its stimulant effects Promotes alertness, reduces tiredness May have beneficial roles in disease reduction when consumed in coffee Coffee is believed to have antioxidant and anti-inflammatory properties May increase the risk of miscarriage and kidney stones

Question 71

Alcohol

Answer 71

= psychoactive drug found in certain foods and beverages Provides 7 kcal/g Higher levels of consumption increase risk for cancers, liver cirrhosis, confusion, dementia, malnutrition, all-cause mortality… However, light to moderate amounts (1-2 servings per day) may provide a slightly lower risk of CVD

Question 72

Alcohol Metabolism

Answer 72

90% of alcohol is metabolized and eliminated at the liver Alcohol dehydrogenase aldehyde dehydrogenase are the enzymes responsible for metabolizing alcohol Genetic changes can negatively impact the activity of these enzymes May result in facial redness, nausea, sweating, dizziness and racing heart rate when alcohol is consumed

Question 73

Hangovers

Answer 73

Typically occur 6+ hours after drinking Symptoms include vomiting, tiredness, decreased attention, decreased concentration, stomach pain and disturbed sleep May be due to direct effect of alcohol, acetaldehyde buildup, or congeners Best way to avoid a hangover is to moderate or abstain from alcohol consumption

Question 74

Views of Water

Answer 74

``` western lens Important natural resource Commodity Used for industry, agriculture Used by humans as a nutrient ``` ``` indigenous lens Tied to our existence Part of who we are Has a life of its own “Mother Life’s blood” ```

Question 75

Whanganui River

Answer 75

Found in New Zealand Following an 140-year long lobbying effort, was the first river in the world to be given the same legal rights as humans “We can trace our genealogy to the origins of the universe. And therefore, rather than us being masters of the natural world, we are part of it. We want to live like that as our starting point. And that is not an anti-development, or anti-economic use of the river but to begin with the view that it is a living being, and then consider its future from that central belief”

Question 76

Carbohydrates

Answer 76

The term carbohydrate denotes what their structure is composed of carbo (carbon) and hydrate (hydrogen and oxygen) There are three main types of carbohydrates: sugars, starches and fibre All three are made up of monosaccharides, or sugars

Question 77

Monosaccharides (Single Sugars)

Answer 77

There are three main monosaccharides found in the foods we eat Glucose is the most common monosaccharide glucose =blood sugar fructose = fruit sugar galactose = milk sugar

Question 78

Disaccharides (Double Sugars)

Answer 78

The dietary monosaccharides found on the last slide are used to make up the three most common dietary disaccharides

Question 79

Extrinsic vs. Intrinsic Sugars

Answer 79

Intrinsic sugars are those naturally found in foods Extrinsic sugars, AKA added sugars, are added into food by manufacturers to increase their sweetness Extrinsic and intrinsic sugars are chemically identical However, foods higher in extrinsic sugars are more likely to be nutrient poor and energy dense and may increase risk of disease Extrinsic Sugars Must be Grouped Together on an Ingredients List

Question 80

Oligosaccharides (Few Sugars)

Answer 80

Oligosaccharides have between 3 and 10 monosaccharides in their chain They are considered fibres, because humans lack the enzymes needed to digest them Most common oligos = fructooligosaccharides (FOSs) and galactooligosaccharides (GOSs) They are prebiotics because digestive bacteria can use them for food

Question 81

Polysaccharides (Many Sugars)

Answer 81

Polysaccharides have more than 10 monosaccharides in their chain Polysaccharides are typically composed of long glucose chains Two main types of polysaccharides: Starch (humans have the enzymes needed to break it down) Fibre (humans do not have the enzymes needed to break it down

Question 82

Starch

Answer 82

= long glucose chain that is either straight (amylose) or branched (amylopectin)

Question 83

Fibre

Answer 83

There are many types of fibre Ex. cellulose, dextrin, inulin They are classified as either soluble or insoluble (next slides) Compared to starch, the bonds that hold adjacent glucose molecules together are different We lack the enzymes needed to break these bonds Accordingly, there is no chemical digestion of fibre in the small intestine

Question 84

Soluble Fibre

Answer 84

Soluble fibre dissolves in water It is found in apples, beans, peas, citrus fruits… Soluble fibre may help to regulate blood glucose and lower blood cholesterol Bacteria in the large intestine can ferment soluble fibre to produce short-chain fatty acids Provide 2-3 kcal of energy

Question 85

Insoluble Fibre

Answer 85

Does not dissolve readily in water Passes through digestive tract virtually unchanged Found in wheat, bran, beans, potatoes, cauliflower… May promote digestive health

Question 86

Glycogen

Answer 86

= storage form of carbohydrate We can only store so much carbohydrate – typically around 0.5-2 kg Glycogen is composed of long chains of glucose molecules We have glycogen stored in our muscles and around out liver

Question 87

Refined vs. Unrefined Carbohydrates

Answer 87

Unrefined sources of carbohydrates are those consumed in their entire form i.e. the entire grain is used Ex. Whole grain wheat They are more nutrient dense, higher in fibre, phytochemicals Refined sources of carbohydrates have part of the grain removed, typically the bran and germ layer

Question 88

Lactose Intolerance

Answer 88

Caused by insufficient secretion of the enzyme lactase Since lactose cannot be digested in small intestine, bacteria in the large intestine ferment it Leads to the production of methane gas Symptoms include cramps, bloating, diarrhea, abdominal pain when lactose is consumed

Question 89

Glycemic Response and Glycemic Index

Answer 89

Glycemic response = spike in blood glucose that follows a meal once glucose enters the general circulation Diets that produce a lower GR associated with a lower risk of type 2 diabetes, CVD and obesity = relative ranking of a food's potential to spike blood sugar on a 100-point scale Glucose scores 100 Glycemic load may be more accurate then glycemic index, because it also takes into account how much carbohydrate is actually in that food

Question 90

Blood Sugar Regulation – the Role of Insulin and Glucagon

Answer 90

Our bodies try to establish glucose homeostasis Insulin and glucagon are blood glucose-regulating hormones They are secreted by the pancreas When blood glucose is not in balance, it can have negative effects Hypoglycemia, low blood glucose, can affect energy levels etc. Hyperglycemia, high blood glucose, if chronic, can lead to diabetes

Question 91

The Endocrine vs. Exocrine Pancreas

Answer 91

Pancreas secretes insulin and glucagon into the blood (endocrine function) in order to regulate blood glucose Pancreas secretes pancreatic juice into the digestive tract (exocrine function) to facilitate digestion

Question 92

Glucagon and Blood Glucose

Answer 92

When blood glucose levels drop, the pancreas releases glucagon Glucagon increases blood glucose through three main processes: Glycogenolysis: the conversion of glycogen to glucose. Gluconeogenesis: the conversion of certain amino acids into glucose. Lipolysis: the breakdown of stored lipids. The glycerol from triglycerides can then be used to make glucose.

Question 93

Carbohydrates Spare Proteins

Answer 93

If the body does not consume enough carbohydrates, certain amino acids will be used to make glucose through process of gluconeogenesis This leads to the breakdown of body proteins Getting enough carbohydrate in the diet minimizes the breakdown of body proteins

Question 94

Fat Burns in Carbohydrate Flame

Answer 94

Sufficient dietary carbohydrates are needed in order to maintain the citric acid cycle If the diet is very low in carbohydrates, the products of lipid metabolism cannot enter the citric acid cycle and will instead form ketones

Question 95

diabetes in indigenous lens

Answer 95

In Canada, Type 2 diabetes is 2-3 times more common in Indigenous populations This is believed to be due, in part, to colonization and cultural loss Indigenous individuals who retain their culture through language are less likely to develop diabetes

Question 96

Type 1 Diabetes

Answer 96

Approx 10% of cases Aka juvenile or insulin-dependent diabetes The immune system attacks the insulin-secreting cells of the pancreas = no insulin secretion, glucose cannot enter cells, blood glucose remains high

Question 97

Type 2 Diabetes

Answer 97

Approx. 90% of cases Mainly evidenced by insulin resistance Cells lose their sensitivity to insulin, don’t respond to it ``` risk factors: Obesity Physical inactivity Diets high in processed foods, sugar, fat Genetics Family history Gestational diabetes ```

Question 98

Gestational Diabetes

Answer 98

Elevated blood glucose and impaired glucose management that first occurs during pregnancy Approx. 5% of pregnant women develop it Increases future risk for type 2 diabetes in mother

Question 99

Prevention of Diabetes

Answer 99

``` Type 1 No preventative measure has been established Type 2 Lifestyle changes Weight balance, loss Reduction in caloric intake, fat Physical activity Medication ```

Question 100

Hypoglycemia

Answer 100

= low blood glucose Symptoms include dizziness, extreme hunger, headache, irritability, tiredness and mental confusion Reactive hypoglycemia = due to excessively high dose of insulin Non-reactive hypoglycemia = various causes may be due to fasting, medications, pregnancy, alcohol abuse and liver, heart, kidney disorders

Question 101

FODMAPs and Irritable Bowel Syndrome

Answer 101

Short-chain carbohydrates are not fully absorbed in the small intestine and are fermented by bacteria in the large intestine, producing gas May promote IBS symptoms Reducing these FODMAPs (fermentable oligosaccharides, disaccharide, monosaccharide and polyols) may improve IBS symptoms

Question 102

Fibre and Colon Cancer

Answer 102

Dietary fibre intake may reduce the risk of developing cancers of the large intestine Individuals who consumed the most fibre had the lowest risk of developing cancers in different parts of the colon Fibre may dilute the concentrations of cancer-causing agents, promote their removal and/or minimize the damage they can cause

Question 103

Triglycerides

Answer 103

=the main dietary lipid Have a glycerol backbone with three fatty acids (“fats”) attached to it Fatty acids differ in their degree of saturation, length and/or their geometric organization

Question 104

Degree of Saturation of Fatty Acids

Answer 104

Saturated fatty acids = no double bonds They are accordingly saturated with hydrogens Unsaturated fatty acids = one (mono-) or more (poly-) double bonds Polyunsaturated fatty acids (PUFAs) are named according to where the double bond is when counting from the omega end Ex. Omega-3 PUFAs

Question 105

Essential Fatty Acids

Answer 105

PUFAs with the double bond before the 9th position The body cannot make them itself, therefore they are essential There are two essential fatty acids: alpha-linoleic acid (omega-3) and linolenic acid (omega-6) They can be used to synthesize other omega-3/-6s They can be used to form eicosanoids = hormone-like molecules

Question 106

Length of Fatty Acids

Answer 106

Long-chain fatty acids are found in a variety of animal products, some plants Medium-chain fatty acids are found in tropical oils Short-chain fatty acids are made by bacteria when they ferment indigestible carbs

Question 107

Geometric Structure of Fatty Acids

Answer 107

Unsaturated fatty acids can have a cis or trans configuration This refers to the location of hydrogen atoms around the double bond Trans fatty acids can be artificially made through the process of hydrogenation These artificial/industrial trans fats significantly increase risk of CVD

Question 108

Sterols

Answer 108

Have a hydrocarbon chain arranged in a ring formation Also hydrophobic Play a variety of structural and functional roles in the body Ex. cell membrane structure, hormone formation Can be consumed from both plant and animal sources animal derived sterols: Most common = cholesterol Has many important roles in the body Cell membrane structure Precursor for vitamin D Precursor for estrogen, testosterone Liver and other body structures can synthesize their own cholesterol, so it is not necessary from the diet

Question 109

Phospholipids

Answer 109

Their amphiphilic nature (having a hydrophilic and a hydrophobic end) gives them special properties and functions They can form a bilayer when immersed in water Ex. Phospholipid bilayer of the cell membrane They can act as emulsifiers They can carry other lipids around the body Ex. lipoproteins

Question 110

Lipid Digestion

Answer 110

Triglycerides must first be digested into glycerol and fatty acids Bile emulsifies lipids, lingual/gastric/pancreatic lipases digest them

Question 111

Lipid Absorption

Answer 111

1. the micelle breaks down. its loupes contents are absorbed into the small intestine cells through passive diffusion 2. lipids gets wrapped in phospholipids as they exit the small intestine cell and enter the centre of villus. the resulting structure is called a chylomicron 3. chylomicrons are too large to enter the blood. instead they enter lacteals

Question 112

Lipid Transport

Answer 112

The hydrophobic nature of lipids makes them incapable of dissolving in the watery environments of the small intestine lumen, blood and lymph They accordingly need lipoproteins, lipid transporters, to carry them around the body

Question 113

Energy Provision

Answer 113

Lipids provide 9 kcal/gram If carbohydrates are adequate in the diet, triglycerides are metabolized and their products enter the citric acid cycle and the electron transport chain to yield ATP If carbohydrates are inadequate in the diet, ketones are formed

Question 114

Lipid Storage vs. Lipid Metabolism

Answer 114

At an energy surplus, extra energy is stored as lipid in adipose tissue (fat tissue) At an energy deficit, lipids are retrieved from adipose tissue

Question 115

Membranes

Answer 115

The membranes of cells and the membranes of cellular organelle are composed of phospholipids

Question 116

Transport and Storage of Fat Soluble Vitamins

Answer 116

Vitamins A, D, E, and K are fat-soluble vitamins Since they are hydrophobic, they require a lipoprotein for their transport They are also stored in adipose tissue

Question 117

Synthesis of Other Key Molecules

Answer 117

Cholesterol-derived molecules include: Steroid hormones, bile salts, vitamin D, estrogen, testosterone Essential fatty acid-derived molecules include: Eicosanoids, endocannabinoids

Question 118

Lipids and Cardiovascular Disease

Answer 118

CVD compromises the cardiovascular system’s ability to deliver cellular needs (ex. Oxygen, nutrients) and remove wastes (ex. CO2) Atherosclerosis, the build-up of fatty materials in artery walls, is a type of CVD that causes heart attacks and some strokes Certain lipids can increase or decrease the risk of developing atherosclerosis Depends on the lipid

Question 119

Trans Fatty Acids and CVD

Answer 119

On a per-calorie basis, trans fats appear to increase the risk of [heart disease] more than any other macronutrient” (Mozaffarian et al., 2006).” Are known to increase: Ratio of LDL to HDL Risk of CVD Risk of CVD mortality To reduce/avoid trans fats, minimize the consumption of processed and ultra-processed foods, especially those that are hydrogenated

Question 120

Saturated Fatty Acids

Answer 120

Diets high in saturated fat: Increase LDL → which increases risk of CVD = lipid hypothesis However, a direct link between saturated fat and CVD has not been established Replacing saturated fats (mainly found in animal products) with unsaturated fats (mainly found in plant products) may lower potential risk

Question 121

Polyunsaturated Fatty Acids

Answer 121

When PUFAs replace saturated fat, LDL levels decrease | PUFAs that are essential amino acids have also been studied for their roles in CVD (next slide)

Question 122

Essential Fatty Acids

Answer 122

Omega-3 fatty acids Have several cardioprotective effects including decreasing inflammation, blood cholesterol, vasoconstriction and blood clotting However, supplementation of omega-3 has not been shown to decrease cardiovascular events Omega-6 fatty acids Thought to increase risk of CVD because they Increase inflammation and blood clotting However, results of RCTs have been mixed Both omega-3 and omega-6 fatty acids have protective effects on the brain Are being

Question 123

Cholesterol

Answer 123

For most people, dietary cholesterol has a minimal effect on increasing LDL and cardiovascular risk The body makes less cholesterol when more is consumed, LDL levels don’t rise However, 25-30% of people are believed to be cholesterol hyper-responders Their LDL does go up when more cholesterol is consumed

Question 124

Protein Structure

Answer 124

Proteins are Folded Amino Acid Chains ``` Amino acids have three main groups: A nitrogen-containing amine group A carboxylic acid A side chain (Rx) There are 21 amino acids Structurally, they differ only in their side chain ```

Question 125

Essential vs. Non-Essential Amino Acid

Answer 125

Nine amino acids are essential The non-essential amino acids can be made by modifying other amino acids Through process of transamination Conditionally essential amino acids are non-essential amino acids that become essential when the body cannot synthesize enough of them

Question 126

Complete vs. Incomplete Proteins

Answer 126

Complete proteins are foods that have all nine essential amino acids All animal sources are complete, as are soy, quinoa, buckwheat Incomplete proteins are foods that are missing one or more essential amino acids Plant sources are typically incomplete The amino acid that is lacking = limiting amino acid

Question 127

Protein Synthesis

Answer 127

To become part of a fully functional protein, amino acids must bind together in a specific order Our DNA holds the instructions for the sequence of amino acids needed in order to build specific proteins We draw on the amino acid pool to make these chains

Question 128

Primary Structure of a Protein

Answer 128

The first level of protein structure arises from adjacent amino acids bonding to each other Peptide bonds lead to the formation of a polypeptide This polypeptide is not yet a protein Must fold into secondary, tertiary, perhaps quaternary structure

Question 129

Secondary Structure of a Protein

Answer 129

Hydrogen bonds between non-adjacent amino acids lead to the formation of: Alpha helices Beta-pleated sheets

Question 130

Tertiary Structure of a Protein

Answer 130

Interactions between amino acids side chains leads to further folding of the polypeptide chain This may result in a functional protein

Question 131

Quaternary Structure of Protein

Answer 131

Some proteins have a quaternary structure =several proteins with a tertiary structure bind together to form the final protein Each of these is called a protein subunit

Question 132

Denaturation of a Protein

Answer 132

A protein is denatured when it loses its folded three-dimensional structure Also loses its function Acids, heat, agitation can all denature proteins This is sometimes desirable ex. Food preparation

Question 133

protein body structure

Answer 133

Bones, muscles, skin and every body organ contain protein Collagen is the main structural protein Elastin is another key structural protein Permits elasticity

Question 134

protein transport

Answer 134

Protein tracks in cells allow substances to walk along them, permitting transport around the cell Protein channels regulate movement into and out of the cell The blood protein hemoglobin transports oxygen around the body

Question 135

protein Movement

Answer 135

Myosin and actin are proteins found in muscle When myosin proteins attach to actin proteins and kink their heads, muscle contraction occurs Allows our bodies to produce movement

Question 136

protein fluid balance

Answer 136

Water is attracted to the positive and negative charges of the amino acids found in blood proteins This draw water into the blood and out of the extracellular space If blood proteins are low, fluid can build up in the extracellular space, leading to edema

Question 137

protein protection from disease

Answer 137

Collagen in skin helps to restrict what can enter the body If infectious agents enter, proteins called antibodies stick to these agents, promoting their removal and limiting the harm they can cause

Question 138

protein energy

Answer 138

While proteins provide 4 kcal/gram, they are a minor source of energy to the body It is wasteful to deaminate an amino acid so it can be metabolized to generate ATP The body prefers to use protein for all its various other functions

Question 139

Protein Deficiency

Answer 139

Marasmus = wasting syndrome Occurs when energy and protein are deficient Promotes anemia, dehydration, heart irregularities, body temperate dysregulation Kwashiorkor Believed to occur when protein is deficient, but energy is sufficient Evidenced by a distended, swollen abdomen and an otherwise slim appearance

Question 140

Protein and Body Weight

Answer 140

The primary dietary factor that promotes weight gain is a caloric intake that is consistently above the body's needs Whether a high/low-protein diet leads to weight gain depends on the total calories consumed However, protein may promote a caloric deficit by: Promoting fullness Contributing to carbohydrate and lipid metabolism Requiring more energy to digest and absorb it i.e. it has a higher thermic effect

Question 141

Protein and Bone Health

Answer 141

In bone, collagen forms a matrix that minerals (ex. Calcium) harden However, high protein diets can promote calcium excretion Overall, high protein diets do not seem to negatively affect bone health

Question 142

Protein and Kidney Health

Answer 142

High protein diets tax the kidneys because they have more waste products to excrete For those with reduced kidney function, consuming protein at the recommended intake level (0.8 g/kg), and not beyond it, is recommended

Question 143

Ways to Assess Protein Quality

Answer 143

Protein digestibility corrected amino acid score (PDCAAS) Compares the amino acid content of a food against a standard amino acid profile. The highest score that can be achieved is 1.0 =industry standard Digestible indispensable amino acid score (DIAAS) Measures how well amino acids are digested in the ileum and more closely estimates the amount of amino acids absorbed by the body Database is still being built Protein efficiency ratio (PER) How much weight an animal gains when consuming a specific amount of protein, divided by the amount of food it consumed Used in Canada

Question 144

Branched-Chain Amino Acids

Answer 144

=essential amino acids that have a branched side chain They account for 35-40% of the dietary essential amino acids found in body protein Have been shown to reduce muscle damage associated with weight training Especially if consumed before exercise Can be consumed from whole sources, do not have to come from supplements!

Question 145

An Indigenous Lens: Protein Quality of Game Meats vs. Processed Meats

Answer 145

Traditional Indigenous diets were very high in protein due hunting and fishing practices However, with colonization came limitations on these practices With this, there has also been a shift towards processed meats Believed to negatively affect protein quality of modern Indigenous diets Game meats have more total protein and tryptophan than processed meats Tryptophan is an essential amino acid involved in many processed including mood regulation and sleep Shifting back to a traditional Indigenous diet may help correct potential deficiencies

Question 146

Health Benefits of Vegetarian Diets

Answer 146

Diets are high in fibre and phytochemicals and low in saturated fats Vegetarians are more likely to have lower BMIs, total cholesterol and LDL They are also at lower risk for heart disease, cancer and CVD mortality

Question 147

Risks of Vegetarian Diets

Answer 147

They are lower in vitamin D, omega-3 fatty acids, calcium, iron and zinc Vitamin B12 is only found in animal products (with the exception of nutritional yeast) Supplementation is recommended if these are not sufficient in diet

Question 148

Vitamin Overview

Answer 148

Vitamins are organic micronutrients They facilitate body processes They are either fat-soluble or water-soluble Vitamins Can Function as Coenzymes

Question 149

water-soluble vitamins

Answer 149

B vitanmins, vitamin C

Question 150

The B Vitamins

Answer 150

A group of eight vitamins that act as coenzymes for energy metabolism Many have other roles as well Plants and animals naturally contain B vitamins and they are also fortified into foods

Question 151

Vitamin B1: Thiamine

Answer 151

Plays a roles in muscular contraction, nerve conduction and is required for ATP synthesis Also part of the coenzyme thiamine pyrophosphate Required for citric acid cycle No known toxicity

Question 152

Thiamine Deficiency

Answer 152

Rare in Canada The brain is particularly susceptible to thiamine deficiency Can promote neuronal death In developed world, typically associated with alcoholism Can lead to Wernicke/Korsakoff syndrome short-term memory loss, confusion, disorientation and changes in eye movements Korsakoff syndrome has more severe and permanent neurological symptoms In developing world, associated with malnutrition Can lead to BeriBeri Wet BeriBeri Negatively impacts the cardiovascular system and can lead to heart failure Dry BeriBeri Negatively impacts the nervous and muscular systems, potentially leading to muscle paralysis Can also lead to Wernicke/Korsakoff syndrome

Question 153

Vitamin B2: Riboflavin

Answer 153

Riboflavin helps form two important coenzymes: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) Recall, FAD = electron transporter required for electron transport chain They are also involved in: Conversion of the amino acid tryptophan to niacin Maintaining appropriate levels of homocysteine sources: chicken, nuts, eggs, celery, cheese, milk

Question 154

Riboflavin Deficiency

Answer 154

``` Rare More common in vegetarians Hormonal abnormalities may promote it Can lead to ariboflavinosis skin disorders, swelling in the mouth and throat, dry and cracked lips, red eyes and hair loss ```

Question 155

Vitamin B3: Niacin

Answer 155

Forms the coenzyme nicotinamide adenine dinucleotide (NAD) Recall, NAD = electron transporter required for electron transport chain NAD is required by more than 400 enzymes! Involved in more reactions than any other vitamin

Question 156

Niacin Deficiency

Answer 156

Causes pellagra 4Ds of pellagra: dermatitis, diarrhea, dementia, death Pellagra plagued the Southern US in the early 1900s before its cause was known Southern diet was high in corn, wheat and rice = low in niacin

Question 157

Vitamin B5: Pantothenic Acid

Answer 157

Helps form coenzyme A Required for acetyl CoA Essential for energy metabolism Deficiency, toxicity = rare sources: Pantothen = everywhere Found in a wide variety of food

Question 158

Vitamin B5: Pantothenic Acid

Answer 158

Helps form coenzyme A Required for acetyl CoA Essential for energy metabolism Deficiency, toxicity = rare sources: Pantothen = everywhere Found in a wide variety of food

Question 159

Vitamin B6: Pyridoxine

Answer 159

= generic name for six vitamers Act as coenzymes in more than 100 reactions Ex. Energy metabolism Also help form the neurotransmitters serotonin and norepinephrine Also helps lower homocysteine levels by converting it to cysteine special uses: upplementation has been used for: Improving cognitive function Reducing CVD risk Reducing PMS symptoms Reducing vomiting and nausea in pregnancy

Question 160

Vitamin B6 Deficiency and Toxicity

Answer 160

Deficiency = rare, typically in combination with other B vitamin deficiencies In pronounced cases can lead to microcytic anemia Can promote fatigue, lethargy Toxicity = rare; typically due to over-supplementation (>1000 mg/d) Can promote loss of control over body movements

Question 161

Vitamin B7: Biotin

Answer 161

Generic name for five vitamers that function as coenzymes Involved in energy metabolism, cell-signalling, DNA structure/function Special uses: Biotin is sold to improve hair, nail, skin health However, clear benefit has not been scientifically established

Question 162

Biotin Deficiency and Toxicity

Answer 162

Deficiency = rare May occur with a genetic disorder called biotinidase deficiency Hari loss, red eyes, rashes Can progress to seizures, depression, muscle disorders Toxicity = rare But over-supplementation can compromise laboratory test results

Question 163

Vitamin B9: Folate/Folic Acid

Answer 163

Folate = basic form (food), Folic acid = acids form (supplements) Coenzyme in DNA/RNA synthesis, amino acids metabolism Also involved in conversion of homocysteine to methionine

Question 164

Folate Deficiency

Answer 164

Deficiency during pregnancy can lead to neural tube defects Can cause birth defects such as spina bifida and anencephaly Can lead to megaloblastic anemia Red blood cells are immature, large, misshapen and unable to properly carry oxygen Symptoms include tiredness, weakness and heart irregularities Folate deficiency has also been studied for its potential link with autism, but firm link has not been established

Question 165

Vitamin B12: Cobalamin

Answer 165

Vitamin B12 vitamers are collectively known as cobalamins Required for DNA synthesis, red blood cell formation, brain function Also acts as coenzyme for conversion of homocysteine to methionine Has also been studied for reduction in dementia risk – evidence is currently lacking to sources:Found only in animal products With exception of nutrition yeast Supplementation is recommended for vegans, vegetarians

Question 166

Vitamin B12 Absorption

Answer 166

Factors that negatively affect the stomach (ex. Atrophic gastritis) can compromise the release of intrinsic factor, negatively affecting B12 absorption More common in older adults

Question 167

Vitamin B12 Deficiency and Toxicity

Answer 167

Deficiency can lead to megaloblastic anemia Can also promote balance issues, depression, poor memory, confusions Toxicity = rare However, can interact with certain medications

Question 168

Vitamin C: Ascorbic Acid

Answer 168

Critical for collagen formation Also involved in protein metabolism, iron absorption Vitamin C is an Antioxidant special uses: Immune system effects Vitamin C supports the proper function of the immune system May lower risk of developing colds if taken before they occur Especially in certain athletes Chronic disease prevention Has been studied for potential to reduce cancer, CVD risk However, supplementation has not been shown to reduce risk

Question 169

Fat-Soluble Vitamins

Answer 169

vitamin A, D, E , K

Question 170

Vitamin A

Answer 170

Vitamin A has several vitamers = retinoids Provitamin A is found in plants and its vitamers are collectively known as carotenoids. Must be converted into retinols Preformed vitamin A is found in its almost-active forms: retinol and retinal ester; found in animal products The body must convert retinols into retinal and retinoic acid = active form of vitamin A Vitamin A is Critical for Visual Pathway

Question 171

Other Functions and uses of Vitamin A

Answer 171

Gene expression i.e. Whether genes are turned on/off Immune Function Contributes to formation of infection-fighting T-cells Carotenoid form (plants) functions as an antioxidant Promotes skin health by switching on the genes that cause immature skin cells to become mature and healthy Many skin care products contain retinoids Ex. Accutane, a retinoic acid product is used to treat acne However, can have severe skin, gastrointestinal, nervous and cardiovascular side effects and increase risk of birth defects if taken by pregnant women

Question 172

Sources of Vitamin A

Answer 172

Preformed vitamin A is found in animal products | Provitamin A is found in plant products

Question 173

Vitamin A Deficiency and toxicity

Answer 173

Rare in North America, common in developing countries Often linked with poverty, low diet variability Can lead to xeropthalmia - abnormal dryness of the eye that affects the body’s ability to form tears If untreated, can lead to breaks in cornea, even blindness Night blindness is an early sign of xeropthalmia Carotenoids may turn skin slightly orange, but otherwise have no toxicity symptoms Preformed vitamin A toxicity can have serious side effects Elevated pressure around the brain, dizziness, nausea, headaches and can be fatal Typically due to over-supplementation Has also been evidenced in arctic explorers who consume polar bear liver =excessively high in provitamin A

Question 174

Vitamin D

Answer 174

= generic name for a group of compounds including vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol) Their main role is maintaining calcium homeostasis Increase calcium, phosphorus and magnesium absorption Also plays roles in cellular growth, immune function and the reduction of inflammation Has also been studied for its role in cancer prevention Establishing adequate vitamin D from food may have a role in cancer prevention, but supplementation has not been established to lower risk sources: fish, cheese

Question 175

Vitamin D Deficiency

Answer 175

Common; due to inadequate dietary consumption, limited sun exposure Older adults, individuals with black skin, individuals with obesity, breastfed infants, people who have undergone gastric surgery are all at higher risk In children, can promote rickets In adults, can lead to osteomalacia =softening of bones Can progress to osteoporosis

Question 176

Vitamin D Toxicity

Answer 176

Toxicity from food is rare, typically due to over-supplementation Can promote anorexia, weight loss, increased urination, irregular heart rhythms Can also increase blood calcium Can harden blood vessels, eyes and negatively impact kidneys and heart

Question 177

Vitamin E

Answer 177

generic term for eight vitamers Alpha tocopherol = main one from diet Vitamin E exerts its main functions through its antioxidant role Also involved in immune function, cell signalling Has also been studied for potential to decrease cancer, CVD, Alzheimer’s risk However, supplementation has not been shown to decrease risk

Question 178

Vitamin E Deficiency and Toxicity

Answer 178

Deficiency = rare; typically due to compromised fat absorption Symptoms may include peripheral neuropathy, movement difficulties, muscle disorders and an impaired immune response Toxicity is due to over-supplementation Increases mortality rate Has been linked to lung illnesses in those that vape High levels of vitamin E were found in the blood of individuals with vaping-related lung issues such as difficulty breathing, chest pain, fatigue and vomiting

Question 179

Vitamin K

Answer 179

Named for the Danish word for coagulation (blood clotting) Prothrombin synthesis is dependent on a vitamin K coenzyme Prothrombin is needed for the pathway that leads to the formation of sticky fibrin fibres – which help red blood cells clump together

Question 180

Vitamin K Deficiency and Toxicity

Answer 180

Deficiency is rare Except in newborns, those with compromised absorption, those who overuse antibiotics Can lead to excessive bleeding, hemorrhaging Newborns get a shot of vitamin K to prevent this Toxicity has not been observed

Question 181

An Indigenous Lens: Are Minerals Living Things?

Answer 181

Western science defines organic matter as that which contains carbon and comes from living things the Indigenous world view thinks much more in terms of [things] being alive…If you talk about a rock in English, you are thinking about it being something static, something fixed…but in Ojibway, when you’re talking about asin or asiniig, you’re talking about something that is alive, something that has a spirit, something that is in motion

Question 182

Overview of Minerals

Answer 182

``` Minerals are elements that form solid compounds and that are not bound to carbon = inorganic Divided into: Major minerals Required in higher amounts from diet Minor/trace minerals Required in lower amounts from diet ```

Question 183

Mineral Bioavailability

Answer 183

Bioavailability = availability in food as well as its propensity to be absorbed and available for use within the body Minerals are found in both plants and animals Mineral content of plants depends on the soil Mineral content of animals depends on what they eat Animal products, especially from larger animals, are a better source of minerals than plant products

Question 184

Plants Contain Compounds That Can Negatively Affect Bioavailability

Answer 184

``` Phytates Impair iron, zinc absorption Phytate effects can be reduced by: Soaking certain foods overnight Ex. Soaking beans Fermenting foods Ex. Making sourdough bread Oxalates Impair calcium, iron absorption Tannins Impair iron absorption May have disease-reducing effects Anti-cancer, antioxidant, antimicrobial and inti-inflammatory ``` Glucosinolates Impair iron absorption

Question 185

Calcium

Answer 185

Most abundant mineral in the human body Also abundant in nature Ex. Limestone, chalk, pearls Key signalling mineral Contributes to nerve signalling, key intracellular messenger Required for muscle and heart contraction, gland secretion 99% of body calcium in stored in bones and teeth Promotes their structural integrity

Question 186

Calcium Homeostasis

Answer 186

Maintaining blood calcium is critically important When levels drop, parathyroid hormone (PTH) is released When levels are too high, calcitonin is release Opposes actions of PTH i.e. impairs osteoclast activity, promotes calcium excretion

Question 187

Calcium Deficiency and toxicity

Answer 187

Minor increases are typically asymptomatic Chronically elevated levels can lead to abdominal/bone pain, mental confusion Can progress to the calcification, hardening, of tissues Can lead to cardiac arrest Rarely due to dietary excess, typically due to other chronic conditions

Question 188

Phosphorus

Answer 188

Second most abundant mineral in body | Found within hydroxyapatite – crystal that contains both calcium, phosphorus

Question 189

Phosphorus Deficiency and Toxicity

Answer 189

Since abundant in foods, deficiency is rare Can lead to osteoporosis, seizures, coma, anorexia, muscle weakness, anemia and an increased risk of infection Toxicity is rare May lead to calcification of tissues

Question 190

Sodium

Answer 190

A key electrolyte It is the primary cation of the extracellular space In water, electrolytes become positively/negatively charged ions Their movement leads to the creation of an electrical current Sodium also contributes to fluid balance sources: processed foods,

Question 191

Sodium Deficiency and Toxicity

Answer 191

Deficiency = hyponatremia Typically caused by excessive vomiting, sweating, diarrhea Symptoms include nausea, vomiting, irritability, fatigue, loss of appetite, confusion, muscle weakness and spasm Can progress to loss of consciousness and coma. Toxicity is typically due to excessive loss of body water, which concentrates sodium Symptoms include thirst, weakness, nausea and loss of appetite Can progress to confusion, muscle twitching, and brain hemorrhages

Question 192

Hypertension, Sodium and the D.A.S.H Diet

Answer 192

Hypertension = high blood pressure Increases risk for CVD mortality Risk factors include: Age, African heritage, family history, kidney disease, diabetes, obesity, physical inactivity, stress, alcohol use and tobacco smoke Diet D.A.S.H. = Dietary Approaches to Stop Hypertension D.A.S.H. eating plan emphasizes: whole foods, particularly fruits, vegetables, whole grains, low-fat dairy, poultry, fish and nuts and is high in fiber, potassium, magnesium, calcium and protein D.A.S.H. eating plan limits: red meat, sweets, total fat, saturated fat, cholesterol and sugar D.A.S.H. eating plan + sodium reduction = significant reduction in blood pressure

Question 193

Potassium

Answer 193

Main role is as an electrolyte Main cation of the intracellular space Also contributes to fluid balance Diets higher in potassium associated with lower risk of hypertension

Question 194

Potassium Deficiency and Toxicity

Answer 194

Deficiency typically has not symptoms May promote tiredness, weakness, cramps Can progress to irregular heart rhythm, cardiac arrest Typically due to excessive vomiting, diarrhea Toxicity = rare Typically due to impaired kidney function may promote muscle weakness, heart irregularities, paralysis

Question 195

Chloride

Answer 195

Also functions as an electrolyte In water, becomes the negatively charged ion chloride Maintains water balance Is part of hydrochloric acid (HCl) Table salt, sodium chloride, is our main source

Question 196

Chlorine Deficiency and Toxicity

Answer 196

Deficiency is rarely due to dietary insufficiency Typically due to respiratory issues, vomiting, kidney malfunction Can promote weakness, difficulty breathing, diarrhea, vomiting Toxicity rarely due to dietary excess Typically due to irregular fluid balance Can promote tiredness, muscle weakness

Question 197

Magnesium

Answer 197

Cofactor for more than 600 enzymes Involved in energy metabolism, protein synthesis, DNA/RNA structure, brain development, heart health, bone density Supports formation of hydroxyapatite crystals special uses: Popular dietary supplement Daily supplementation of 600 mg may help reduce migraine headaches Has also been studied for role in promoting heart health, managing blood glucose Prospective epidemiological studies support these claims RCTs are lacking

Question 198

Magnesium Deficiency and Toxicity

Answer 198

Deficiency = rare Symptoms include loss of appetite, nausea, vomiting, fatigue, weakness can progress to cramping, numbness, tingling or heart irregularities, and seizures Toxicity = rare Typically due to over-supplementation, laxative, antacid use Symptoms include diarrhea, nausea and abdominal cramping

Question 199

Sulfur

Answer 199

Third most abundant mineral in body Critical for synthesis of amino acids methionine and cysteine, which contain sulfur and contribute to protein folding Needed for formation of the antioxidant glutathione peroxidase

Question 200

Sulfur Deficiency and Toxicity

Answer 200

Deficiency is rare in those that consume sufficient protein May contribute to protein-energy malnutrition in those who are inadequate Toxicity is rare May promote diarrhea, colitis

Question 201

Iron

Answer 201

Critical for formation of hemoglobin and myoglobin Therefore vital for oxygen transport ``` Heme iron Found in animal products More bioavailable Non-heme iron Mainly found in plant products Less bioavailable Oxalates, phytates, tannins, caffeine and calcium negatively affect bioavailability Vitamin C promotes iron absorption, increases bioavailability ```

Question 202

Iron Deficiency

Answer 202

One of the most common dietary deficiencies Most serious outcome = iron-deficiency anemia Symptoms include lethargy, tiredness, weakness, hair loss, pale skin Can progress to an irregular heartbeat and delayed growth in infants and children ``` More common in vegetarians, women, athletes, pregnancy Stages Mild iron deficiency Low iron levels in blood, bone marrow Marginal iron deficiency Levels in liver, muscle spleen also depleted Iron-deficiency anemia Levels in red blood cells also deplete ```

Question 203

Iron Toxicity

Answer 203

Very toxic at high levels Hepcidin, the body's iron-regulatory hormone, is responsible for keeping iron stores in balance Suppresses the absorption of iron when levels are high Over-supplementation can lead to nausea, vomiting, constipation, faintness, reduced zinc absorption and bioavailability One-time megadose (>60 mg/kg) can lead to iron poisoning Can lead to organ failure, coma, death Typically occurs with children who mistake iron supplements for candy Individuals with rare genetic condition called hemochromatosis have irregular iron absorption, increased risk of toxicity

Question 204

Zinc

Answer 204

Cofactor for more than 100 enzymes Has roles in gene expression, immune function, protein and DNA synthesis, wound healing, growth, development Part of antioxidants superoxide dismutase and glutathione peroxidase Abundant in diet Phytates in plants can limit absorption

Question 205

Zinc Deficiency and Toxicity

Answer 205

Deficiency rarely due to dietary insufficiency Can promote slowed growth, erectile dysfunction, diarrhea, thinning hair and impaired Toxicity typically due to over-supplementation Can promote nausea, vomiting, a metallic taste in the mouth, loss of appetite, diarrhea, abdominal cramps and headaches High dietary intake also limit the absorption of copper and iron and promote their deficiency

Question 206

Manganese

Answer 206

Cofactor for several enzymes Facilitates energy metabolism, bone development, wound healing Is also part of antioxidant superoxide dismutase Abundant in shellfish, plants Foods high in iron can slow its absorption Deficiency, toxicity = rare

Question 207

Copper

Answer 207

Involved in red blood cell synthesis, iron absorption Cofactor for many enzymes Facilitates energy metabolism, DNA/connective tissue synthesis, special uses: Magnetic bracelets often contain copper Are marketed as a treatment for arthritic pain Not supported by quality evidence May promote skin irritation Also been studied for role in CVD, Alzheimer’s prevention Evidence is insufficient to recommend supplementation

Question 208

Copper Deficiency and Toxicity

Answer 208

~25% of Canadians are well below the RDA Can negatively impact iron absorption, promoting iron-deficiency anemia Deficiency symptoms may also include tremors, tingling sensations, awkward walking patterns, numbness and fatigue Toxicity typically due to over-supplementation, genetic conditions Can promote vomiting, diarrhea, yellowing of skin and muscle pain Can progress to liver damage, heart failure, kidney failure and even death

Question 209

Iodine

Answer 209

Essential component of thyroid hormones thyroxine (T4) and triiodothyronine (T3) Have wide-spread metabolic effects Regulation of fuel use, protein synthesis, heartbeat, body temperature regulation, muscle contraction, cell turnover Main source is iodized salt

Question 210

Iodine Deficiency

Answer 210

Affects ~ 2 billion people worldwide; 25% of which experience clinical symptoms Compromises thyroid gland’s ability to make thyroid hormones In adults, can lead to the formation of a goiter In infants, can lead to congenital iodine deficiency syndrome Increases risk of mental deficiencies, deaf mutism, difficulties with muscular control and slowed growth

Question 211

Iodine Toxicity

Answer 211

Iodine poisoning typically due to over-supplementation Can promote diarrhea, nausea, vomiting More severe cases can lead to the swelling of airways, limiting breathing, a lowered heart rate and even coma Can also lead to iodine-induced hyperthyroidism Can promote accelerated heartrate, muscle weakness and unexplained weight loss, goiter

Question 212

Selenium

Answer 212

Has roles in reproduction, the production and metabolism of the thyroid hormones, DNA synthesis Essential component of the antioxidant glutathione peroxidase special uses: Has been studied for potential to reduce CVD risk Those with higher blood selenium levels have reduced risk of CVD However, supplementation does not reduce risk Has also been studied for potential to reduce cancer risk Those with higher blood selenium levels have reduced risk of breast, lung, colon, prostate cancer However, supplementation has not been established to reduce risk sources: Content in plant foods varies significantly depending on soil quality

Question 213

Selenium Deficiency

Answer 213

Rare in Canada, affects 1 billion+ people worldwide Increases risk of male infertility, muscle weakness, fatigue, hair loss and a weakened immune system Selenium deficiency + secondary stress (ex. Viral infection) are at higher risk for Keshan Disease = potentially fatal heart disease Climate change is predicted to decrease selenium content of soil by more than 50%

Question 214

Selenium Toxicity

Answer 214

Increases risk of hair loss, nail discoloration, muscle and joint pain, headache and gastrointestinal symptoms Early symptoms may include a metallic taste in the mouth and breath that smells like garlic Selenium poisoning typically due to over-supplementation Can promote neurological symptoms, breathing problems, kidney failure, heart attack and, though rare, even death Ex. Outbreak of selenium poisoning in 2008 due to a dietary supplement that had 200X the stated amount of selenium

Question 215

Molybdenum

Answer 215

Cofactor for enzymatic reactions Helps to break down sulfites, which can promote allergic reactions, diarrhea, breathing difficulties Content varies by soil quality Deficiency is rare Toxicity typically due to over-supplementation May affect growth, promote kidney failure or promote the development of seizures and brain damage

Question 216

Fluoride

Answer 216

ion of the mineral fluorine Technically not essential since not required for growth or to sustain life However, important for the formation of fluorapatite crystals Mineralize teeth, strengthen enamel Water fluoridation = “greatest public health achievements of the 20th century” – Center for Disease Control and Prevention Reduces risk of tooth decay by 35% However, many people are against it due to: Cost Ability to get fluoride from toothpaste, treatments Not wanting to tamper with water supply Increased risk of fluorosis However, levels in water are limited to prevent fluorosis

Question 217

Overview of Energy Balance

Answer 217

Energy = ability to do work Energy intake = total energy consumed from food Energy expenditure = energy used to fuel basal metabolism, physical activity, processing food Energy balance = when energy intake = energy expenditure

Question 218

Energy Intake

Answer 218

Carbohydrates, lipids, proteins = the three energy-yielding nutrients Alcohol (7 kcal/g) also provides energy, but not a nutrient

Question 219

Energy Expenditure

Answer 219

We burn energy for three main purposes: Basal metabolic rate (~60-75%) Diet-induced thermogenesis(~10%) Physical activity (~15-30%)

Question 220

Basal Metabolic Rate (BMR

Answer 220

BMR = the amount of energy the body needs to perform its most basic, life-sustaining functions over a period of time Ex. Breathing, heart beat, nerve signalling When we say someone has a fast metabolism, we typically mean that they burn a lot of calories to sustain their body, even before physical activity is factored in They may therefore be less likely to gain fat mass factor that determines: Main controllable factor = lean body mass

Question 221

Diet-Induced Thermogenesis

Answer 221

AKA specific dynamic action, thermic effect of food = energy that is used and dissipated as heat following food intake More energy is required to process protein compared to other nutrients However, at most, DIT accounts for 15% of energy expenditure

Question 222

Energy Retrieval

Answer 222

An energy deficit occurs when energy intake is less than energy expenditure When a consistent energy deficit is maintained, lipids are removed from adipocytes, decreasing fat mass and weight

Question 223

obesity Energy Storage

Answer 223

When energy intake is higher than energy expenditure, excess energy is mainly stored as lipid within our adipocytes, found within adipose tissue As adipocytes grow in size and number, fat mass and total weight increase

Question 224

Adipocytes and Adipokines

Answer 224

Adipocytes secrete adipokines = messengers that communicate with other body tissues Ex. leptin Below a certain level of fat mass, adipokine secretion has a health-promoting maintaining effect Above a certain level of fat mass (obesity), adipokines are more likely to promote low-grade inflammation and disease

Question 225

Leptin: The Fullness Hormone

Answer 225

Leptin is an adipokine that acts on the brain’s hypothalamus to promote satiety (fullness) When our fat cells get larger, more leptin is released – this decreases appetite, promoting an energy deficit If leptin production is genetically compromised (extremely rare), obesity results quickly Many individuals with obesity are leptin resistant

Question 226

obesity food consumption

Answer 226

Appetite = drive to consume food Hunger = physiological need to consume food Satiety = sense of fullness that makes us stop eating and keeps us feeling full until the next meal Our appetite and satiety centers are found within the brain’s hypothalamus Receives constant cues that affect appetite

Question 227

obesity food production

Answer 227

The abundance of food and food cues in our environment promote a constant stream of signals to provoke high energy consumption = obesogenic environment Our thoughts interpret what we see, connect it with memory and emotion, and a message may then be sent to our appetite centre about it Also, many food offerings are energy-dense and nutrient-poor

Question 228

obesity Individual Psychology

Answer 228

Stress, mental health status and the way we think about ourselves and our bodies can affect both how much we eat and how much we exercise Recall: our emotional brain communicates with our appetite center Sometimes we are not hungry but want to eat in order to cope with something else that is going on Food has a rewarding effect on the brain

Question 229

Social Psychology

Answer 229

psychology of our social surroundings Can affect food preferences, body size acceptance, physical activity…. Our perceived lack of time may compromise our ability to eat healthy and be active

Question 230

obesity Individual Physical Activity

Answer 230

= main controllable factor that affects energy expenditure Our childhood experiences, physical capacities and perceptions of physical activity can increase/decrease desire to be active. Furthermore, how much we move our body at work and in our leisure time all contribute to our total energy expenditure.

Question 231

obesity Physiology

Answer 231

We all handle energy differently Ex. Different BMRs, hormonal activity, genetics Also, differences in microbiome and appetite regulation can have significant effects on energy balance

Question 232

Microbiome and Energy Balance

Answer 232

Individuals with obesity are more likely to have more Firmicutes in their colon These bacteria are better at harvesting energy from food, increasing energy intake There is also mounting evidence of a gut-brain axis that increases obesity risk =communication between microbiota and brain May affect appetite etc

Question 233

Body Composition

Answer 233

proportion of fat mass vs. lean mass on body | A body that has more lean mass and less fat mass is associated with health

Question 234

Weight and Percent Body Fat

Answer 234

Weight cannot fully capture body composition Body Mass Index (BMI) considers body height and weight, but still does not capture body composition Percent body fat expresses fat mass as a percentage of total mass Better at determining body composition

Question 235

Measuring Body Composition

Answer 235

DEXA/ dual X-ray absorptiometry = low dose X-ray that scans the body in two planes Gives image of the body used to determine body composition Can also indicate bone density Air/Water Displacement

Question 236

Psychological Aspects of Weight Loss and Maintenance

Answer 236

Our psychological health impacts appetite, desire to be active Self-efficacy = belief in our ability to achieve a certain task Setting small, achievable goals, celebrating victories, affirming thoughts can help build it Emotional eating may be used to cope with negative emotions, feelings Positive coping, psychology mechanisms may help decrease it Ex. Talking to others, spending time in nature, journaling, crying, speaking to a counsellor Mindfulness may also help = practice of being aware of and experiencing the present moment with a judgement-free, curious approach ex. Mindful eating, mindfulness meditation

Question 237

Pharmaceutical Interventions for Obesity

Answer 237

``` Orlistat Blocks the activity of lipase in small intestine Fat absorption, caloric intake decrease Liraglutide Increases the activity of GLP-1 Promotes satiety Naltrexone/Bupropion Reduces food cravings by altering the reward circuit in the brain that drives food-seeking behaviour ```

Question 238

Risk Factors for Eating Disorders (EDs)

Answer 238

``` EDs are multifactorial Contributing factors may include: Genetics Female gender Socio-cultural factors Ex. Pressure to be thin Personality Ex. Perfectionism, sensitivity towards reward and punishment History of sexual/physical abuse ```

Question 239

Binge Eating

Answer 239

Occurs in bulimia and binge eating disorder and sometimes in anorexia Main symptom = loss of control eating A bingeing episode: Occurs in a specific amount of time (ex. 2 hours) Typically occurs in the absence of hunger, is typically at a fast rate, occurs while the person is alone, and is associated with feelings of guilt and shame

Question 240

Bulimia Nervosa

Answer 240

Involves binge eating episode + compensation Ex. Vomiting, excessive exercise, laxatives Risk Factors: Preoccupation with food Distorted perceptions around body weight Depression Frequent dieting increase risk Vomiting can damage teeth, cause electrolyte imbalances

Question 241

Binge Eating Disorder

Answer 241

Most common eating disorder Binge eating without compensation Promotes obesity and its related complications Risk factors include: Frequent dieting Inability to interpret hunger/satiety signals

Question 242

Anorexia Nervosa

Answer 242

= significant restriction in energy intake leading to a unhealthfully low body weight Individuals with anorexia often: Have an intense fear of weight gain Feel disturbed by their weight/shape Struggle with self-worth and acceptance Experience amenorrhea It is the psychiatric disorder with the highest mortality rate

Question 243

Orthorexia Nervosa

Answer 243

= an obsession with eating healthy that has negative psychological implications it is the obsession and negative mental health implications of these restrictions that may cause it to be a disordered eating pattern Also, increases risk for micronutrient deficiencies Believed to be promoted by societal pressure toward ‘clean eating’ Signs: Compulsively checking nutrition labels Cutting out foods, nutrients, etc. Limiting food intake to narrow range of foods

Question 244

Physical Activity

Answer 244

PA recommendation: 150 min of mod-vig PA/ week accumulated 10 min at a time + two days per week of resistance training

Question 245

Fuel Use During Physical Activity

Answer 245

Which fuel (energy source) is preferentially used depends on: Duration of PA Intensity of PA i.e. whether PA is aerobic or anaerobic

Question 246

PA Duration vs. Fuel Use

Answer 246

``` The first ~two minutes of exercise are anaerobic Relies on ATP (used up in ~2 s) ATP-CP system (used up in ~10 sec) Anaerobic glycolysis At a moderate intensity, after two minutes, aerobic metabolism dominated Relies on Aerobic glycolysis Aerobic fatty acid metabolism ```

Question 247

Creatine Phosphate-ATP System

Answer 247

Creatine phosphate helps to replenish ATP by donating its phosphate group Helps fuel anaerobic activities

Question 248

Anaerobic Glycolysis is the Main Fuel for Anaerobic Activities

Answer 248

Glycolysis = break down of glucose Glucose is the only dietary fuel that can be used for anaerobic activities Fuels high intensity activities and the first 11-120 seconds of exercise

Question 249

Aerobic Fuel Use Following the First Two Minutes of Exercise

Answer 249

``` Glucose use decreases over time Comes from: Muscle glycogen Blood glucose Lipid metabolism is the main fuel source following the first 20 minutes of exercise Comes from: Muscle triglycerides Adipose tissue lipid stores ```

Question 250

Fuel Use vs. Exercise Intensity

Answer 250

Low-moderate intensity activities = aerobic zone Can use all fuels Preferential use of lipids High intensity activities = anaerobic zone Can only use glucose, ATP-CP for anaerobic processes However, some aerobic metabolism will still take place – can use aerobic lipid metabolism as well

Question 251

Carbohydrate Intake

Answer 251

Glucose is a fuel for both aerobic and anerobic activities However, we store a limited amount as glycogen Consuming sufficient carbohydrates can maximize glycogen stores

Question 252

Pre-Exercise

Answer 252

Pre-exercise meal should be properly timed and have the right balance of nutrients to promote performance and minimize digestive issued A pre-exercise meal that contains carbohydrate is the best established way to maximize time to exhaustion Recommendations: 1-4 g/kg body weight of carbs 1-4 hours before exercising for more than 60 minutes Favour easily digestible carb sources that are low in fibre and fat Minimizes digestive distress Fluid intake is also important

Question 253

Glycogen Supercompensation

Answer 253

Aka carbo-loading = maximizing glycogen stores before a long bout of endurance exercise (ex. Half-marathon) Method: in the two days before event, consume 10-12 g/kg/body weight per day Maximizes time to exhaustion during event

Question 254

During Exercise

Answer 254

Water is the most important nutrient to consume during exercise Can weigh yourself before/after exercise to see how much water was lost, replenish the same amount next time i.e. lose 1 kilogram of weight = 1 litre of lost water For longer bouts of activity, electrolytes also need to be replenished These both help stave off the effects of dehydration

Question 255

Fuels During Exercise

Answer 255

If exercising for less than an hour, no extra fuel is needed during exercise Endurance activities lasting 60+ minutes may require extra fuel Recommendation = 30-60 g/hour of easily digested carbohydrate Ultra-endurance athletes (2.5+ hr) may require up to 90 g/hr

Question 256

Post-Exercise

Answer 256

We have three nutritional priorities following exercise: Promote muscle growth and repair (protein) Protein sensitivity is highest in two-hours following exercise Recommendation: 0.25-0.3 g/kg body weight with 10 g of essential amino acid Refill glycogen stores (carbohydrates) Glucose transport into muscle cells increases in 30-40 minutes following exercise Replenish lost fluids and electrolytes

Question 257

Hydroxymethylbutyrate (HMB)

Answer 257

Compound produced by the breakdown of essential amino acid leucine Decreases protein breakdown while increasing protein synthesis May improve muscle recovery by decreasing muscular damage

Question 258

Other Ergogenic Aids

Answer 258

Vitamin and mineral supplements Can only fix a deficiency Anabolic steroids Similar to testosterone Serious side effects include severe acnes, tendon issues, aggressive behaviours, CVD risks, depression, shrunken testes Cannabis Currently no evidence base to recommend it as ergogenic aid Also, may cause chest pain, reduction in strength