Midterm 1 Flashcards
Def: Nutrition
The science of foods and the nutrients they contain, and of their actions within the body including the social, economic, cultural and psychological implications of food eating
What are the 6 types of nutrients
Carbohydrates, fats, proteins, vitamins, minerals and water
Which nutrients are considered macronutrients
Carbohydrates, fats, proteins
Which nutrients are considered micronutrients
Vitamins and Minerals
Def: Macronutrient
Energy yielding nutrients that allow for ATP production
Def: Micronutrients
Nutrients which facilitated ATP production and are only required in small amounts
Which nutrients are organic
Carbohydrates, fats, proteins, vitamins
which nutrients are inorganic
Minerals and Water
Def: Organic molecules
Molecules that contain carbon and are considered alive
Def: Inorganic molecules
Molecules that do not contain carbon and are considered not alive
Why do we need Macronutrients
The body uses the energy-yielding nutrients as fuel to support body activities or store for later, as well as raw materials for building the body’s tissues and regulating activites
How Many essential vitamins are there
13
What are the two categories of vitamins
Water soluble and fat soluble
How many essential minerals are there
14 (calcium, chromium, copper, fluoride, iodine, iron, magnesium, manganese, molybdenum, phosphorus, potassium, selenium, sodium and zinc)
Are minerals distructable
Minerals are indestructible because they are nonorganic and they promote fluid balance and become structures
How much energy do each of the macronutrients provide
Carbs and proteins are 4Kcal/g and fats is 9Kcal/g
What is the only substance that produces energy that is not a macronutrient
Alcohol and it produces 7Kcal/g
Def: Energy Density
Energy a food provides relative to the amount of food (Kcal/g)
Low density would have high weight and low calorie count, whereas high density would have low weight and high calorie count
How can foods have less that 4Kcal/g
water and fiber have no Kcals but add mass to foods
What are the Energy density classifications (what is considered very low, low, medium and high)
Very low: less than 0.6 Kcal/g
Low: 0.6 to 1.5 Kcal/g
Medium: 1.5 to 4 Kcal/g
High: more than 4Kcal/g
Def: Nutrient Density
Nutrients a food provides relative to the energy it provides
Nutrient dense foods would have high amounts of nutrients compared to the number of calories
low nutrient density food are empty calories
How are energy density and nutrient density related
There is a trade off between the two, food with high energy density will have lower nutrient density and vice versa
Def: The Science of Nutrition
The study of the nutrients and other substances in foods and the body’s handling of them
The Quantitative Science Method
Observation and question Hypothesis Experiment Results interpretation: - supported = theory - not supported = new question
Considerations when conducting experiments
Controls, sample size, placebos, binding, double-blinding
Gold standard for scientific research
Double blind, randomized, placebo-controlled, crossover trial
Variability’s effect on results
Variability is the difference between min and max
High variability = not significant
Low variability = increase in confidence of a correlation
Sample size’s effect on results
Large sample size = decrease risk of coincidence and increased confidence in results
Def: Dietary Reference Intakes (DRI)
Amounts of energy, nutrients, other dietary components that best support health for healthy Canadians and Americans, and tend to be clustered by age and gender
Def: Estimated Average Requirements (ERA)
Enough to cover half of all people
Def: Recommended Dietary Allowances (RDA)
Enough of that nutrient for 98% of all people
Def: Adequate Intake (AI)
Normal intake of the average health person. Used when not enough research to determine RDA
Def: Tolerable Upper Intake Levels (UL)
Highest level of daily intake that is likely to pose no adverse health effects in most human individuals
Def: Acceptable Macronutrient Distribution Ranges (AMDR)
Ranges for kcal from each macronutrient
Carbs 45 - 65%
Fat 20 -35%
protein 10 - 35%
What if you don’t meet nutrient requirements
Body either undergoes a primary deficiency caused by inadequate diet or secondary deficiency caused by problem inside the body, causing a decline is nutrition stores and abnormal functions inside the body resulting in physical signs and symptoms
3 main sections on food labels
Nutrition Facts Table, Ingredient List (in descending order of predominance by weight) and nutrition or diet-related health claims
Nutrients required on new food labels
Fats (saturated and trans), carbs (sugars and fiber), protein, cholesterol, sodium, potassium, calcium, iron
Changes to food label
no longer need vitamins a and c
now need potassium
What is considered a lot of a nutrient and a little
less than 5% if daily value is a little and more than 15% is a lot
Classifications of Health claims
Disease risk reduction claims, function claims, general health claims
Best Before Date
Anticipated amount of time an unopened food product keeps its freshness, taste, nutrition value, or any other qualities claimed by the company
Expiry Date
Must be consumed before that date or discarded after the expiry date
Def: Daily value
The percent of the total amount of that nutrient someone with a 2000kcal diet should consume
Changes made to the new Canada’s food guide
Evidence informed, removed food groups, no mention of serving sizes, plate model, not industry influenced
What is the food recommendation for Canada’s Food Guide
Half of the plate is fruits and vegetables, a quarter of the plate is proteins and a quarter is whole grain foods, water is the drink of choice
Canada’s food guide vegetable recommendations
Contain nutrients such as fiber, vitamins and minerals. fresh, frozen or canned are good
Canada’s Food Guide Whole grain foods recommendations
Contain fiber, vitamins and minerals
Canada’s Food Guide Protiens recommendations
contain protein vitamins and minerals, plant proteins contain more fiber and less saturated fat
Health fats
unsaturated fats, nuts, seeds, avocados, fatty fish, vegetable oils, soft margarine
Unhealthy fats
saturated fats, fatty meats, high fat dairy products, some highly processed foods, some tropical oils
Def: Highly processed foods
processed or prepared foods and drinks that add excess sodium, sugar or saturated fat
Canada’s Food Guide: Healthy eating habits
Be mindful of your eating habits, take time to eat, notice when you are hungry, cook more often, enjoy your food, eat meals with others
What are the challenges of digestion
Balancing tasks of the mouth, passing through the diaphragm, slow steady movement to let reactions occur, lubrication of food, digestive enzymes getting access to all foods, management of waste
Structure of the GI tract
Mouth, esophagus, stomach, small intestine, large intestine, rectum and anus
Functions of the mouth in digestion
Chews and mixes food, saliva lubricates and breaks down carbohydrates
Functions of the pharynx
directs the food from the mouth to the esophagus
Functions of the Epiglottis
protects airway while swallowing
Functions of the esophagus
passes food from the mouth to the stomach
Function of the Esophageal sphincter
Allow passage from mouth to esophagus and from esophagus to stomach while preventing backward flow
Functions of the stomach
adds acid, enzymes and fluid, churns, mixes and grind food into liquid mass creating chyme
Functions of the Pyloric sphincter
Allows passage from the stomach to the small intestine while preventing backflow
Functions of the Small intestine
Secretes enzymes that digest all energy-yielding nutrients to their basic building blocks; cells of wall absorb nutrients into blood and lumph
Functions of Ileocecal valve
Allows passage from small to large intestine while preventing backflow
Functions of the Large intestine
Reabsorbs water and minerals, passes waste (fiber, bacteria and unabsorbed nutrients) along with water to the rectum
Functions of Rectum
Stores waste prior to elimination
Functions of the Anus
Holds rectum closed, opens to allow elimination of waste
Muscles of the stomach
thickest walls of the digestive system, 3 layers, can squeeze from 3 different planes, longitudinal, circular and diagonal
Peristalsis
inner circular muscles contract to push food forward, then relax and the longitudinal muscles contract to loosen the tube
Muscles of the small intestine
circular muscles on the inside and longitudinal muscles on the outside
Segmentation
Circular muscles contract creating segments within the intestine, each time the circular muscles contract and relax the chyme is broken up and mixed with digestive juices
Contents of Secretions
Enzymes and water
Secretions of the Salivary Glands
Target Organ: Mouth
Secretion: Saliva
Action: Fluid eases swallowing and salivary enzyme breaks down carbohydrate
Secretions of the gastric glands
Target Organ: Stomach
Secretion: Gastric Juice
Action: Fluid mixes with bolus, hydrochloric acid denatures proteins, mucus protects stomach cells
Secretions of the Pancreas
Target Organ: Small intestine
Secretion: Pancreatic juices
Action: bicarbonate neutralizes acid gastric juices pancreatic enzymes digest all macronutrients
Secretions of the Gallbladder
Target Organ: Small intestine
Secretion: Bile
Action: Bile emulsifies fat so that enzymes can have access to digest it
Secretions of the intestinal glands
Target Organ: Small intestine
Secretion: Intestinal juice
Action: Intestinal enzymes digest macronutrients fragments, mucus protects the intestinal wall
Absorption
Majority takes place in small intestine, begins 1-4 hours after consumption, requires a continuous blood supple
Intestinal Absorptive Cells
Folded intestinal wall with villi which have microvilli. Microvilli have enzyme for transport
What occurs in the final stages of digestion and absorption
vitamin and mineral absorption, undigested residues continue through the GI tract, exercise the GI muscles and retain water, in the large intestine fiber is fermented and materials are recycled (water, salts…)
What are the two paths nutrients can take when being absorbed
Hepatic portal vein to the liver or into the lymph
What type of nutrients enter the lymph
Larger fats
Properties of the lymph system pertaining to digestion
lymph moves slower than blood and allows large fats to bypass the liver, one-way route, circulates between cells, collects into tiny vessels, lymph collects in thoracic duct and then reenters the bloodstream into left subclavian vein
Steps of circulation through the liver
- Vessels gather nutrients, water and salt from GI tract
- Vessels collect into hepatic portal vein
- Hepatic artery brings oxygenated blood to liver
- Capillaries branch throughout liver
- Hepatic vein gathers all blood in liver and sends it to the heart
What is the negative feedback loop that maintains pH in the stomach
- Food in stomach causes the cells of the stomach wall to start releasing gastrin
- Gastrin stimulates stomach glands to release the components of hydrochloric acid
- Stomach pH reaches 1.5 acidity
- acidity in the stomach causes the cells of the stomach wall to stop releasing gastrin
Function of gastrin
Responds to: Food in stomach
Secreted From: Stomach Wall
Stimulates: Stomach glands
Response: Hydrochloric acid secreted into the stomach
Function of Secretin
Responds to: Acidic chyme in the small intestine
Secreted From: duodenal wall
Stimulates: Pancreas
Response: Bicarbonate-rich juices secreted into the stomach
Function of Cholecystokinin
Responds to: Fat or protein in the small intestine
Secreted From: Intestinal wall
Stimulates: gallbladder, pancreas
Response: Bile secreted into the duodenum, bicarbonate and enzyme-rich juices secreted into the small intestine
Def: Probiotics
Microorganisms in food that benefit health
Def: Prebiotics
Ferment fiber and complex proteins, produce short chain fatty acids, vitamins
Gastrointestinal Bacteria
Present in large numbers in the lower small intestine and large intestine
Def: Healthy microbiota
High diversity and an ability to resist change under physiological stress
Def: Dysbiosis
Lower species diversity, fewer beneficial microbes, presence of pathological bacteria
Transfer supplement experiment
Transferred intestinal microbiota form donors to increase sensitivity to insulin in individuals with metabolic syndrome
What are carbohydrates the primary source of energy for?
brain, red blood cells, neurons
Monosaccharides
Single sugars (single ring), 6C 12H 6O, glucose, fructose and galactose
Disaccharides
Pairs of monosaccharides, maltose, sucrose, lactose
Polysaccharides
large chains of monosaccharides, typically glucose
Glucose
Blood sugar, part of every disaccaride
Fructose
Fruits and Honey, sweetest of all sugars
Galactose
Naturally present in dairy products
Maltose
Glucose + Glucose (eg. Barley)
Sucrose
Glucose + Fructose (eg. table sugar)
Lactose
Glucose + Galactose (eg. Milk)`
Glycogen
Type of polysaccaride, Storage from of glucose, highly branched, reserve energy in animals
Startch
Type of polysaccaride, Storage form of glucose in plants, long branched and unbranched chains, found in grains, legumes, and root crops
Fiber
Type of polysaccaride, structural part of plants, we cannot break down, no energy, 2 classifications (soluble and insoluble), as well as functional fibers (are artificially produced) and resistant starches (Act like fibers, can’t be broken down)
Starch Digestion
Mouth: Salivary amylase breaks down into small polysaccharides and maltose
Small Intestine & Pancreas: Pancreatic amylase breaks it down into small polysaccharides and maltose
Walls of the Small intestine: Disaccharidase enzymes on the surface of the small intestinal cells hydrolyze the disaccharides into monosaccharides
Fiber Digestion
Mouth: Mechanical digestion
Large Intestine: Bacterial enzymes break up some fiber into short-chain fatty acids and gas
Functions of Fiber
Slows down absorption of other nutrients, holds water, regulates bowl activity, binds substance such as bile cholesterol and some minerals to carry them out of the body
Carbohydrate Absorption
Some absorbed through lining of the mouth, most via the small intestine, Glucose and galactose through active transport, fructose via facilitated diffusion, fructose and galactose converted into glucose in the liver
What enzyme hydrolyzes maltose
Maltase
What enzyme hydrolyzes sucrose
Sucrase
What enzyme hydrolyzes lactose
lactase
Symptoms of lactose intolerace
bloating, abdominal discomfort, diarrhea
Causes of Lactose intolerance
Genetics, disease causing damage to intestinal villi, some medicines, prolonged diarrhea, malnutrition
Soluble Fiber
Dissolves in water and forms a gel, slow digestion, fermented by bacteria, blunts blood glucose spike, reduces cholesterol, includes nuts fruits seeds
Insoluble Fiber
Does not dissolve, creates bulk, helps with bowl movements, includes wheat and grain vegetables
