Week 3 Flashcards
what is the correct order of how food moves through the GI tract?
esophagus, stomach, small intestine, large intestine
which of the following is a micronutrient?
-minerals
-vitamins
-carbohydrates
-option a and b
-option a, b, c
minerals and vitamins
*we need them in smaller amounts, making them micronutrients
is water considered a macronutrient?
yes, we need it in a large amount. not an energy yielding nutrient
Food labels in canada began changing january 1st 2017. which of the following is required on new food labels?
potassium, maganese, magnesium, phosphorus
potassium
3 parts of the small intestine in order?
duedenum, jejenum, illeum
What do carbohydrates provide as a nutrient? What are some rich foods containing it?
- provide energy for brain and nervous system
- need in a large amount
- help keep digestive system healthy
- within energy limits, keep body lean
- indigestiable carbohydrates yield little or no energy
carbohydrate rich food:
* plants (almost all of it) (whole grains, legumes, veggies and fruits)
* milk products
* concentrated sugars: soft drinks, candies, cake
How can carbohydrates be categorized?
Simple Carbohydrates
* monosaccharides: single sugar
* disaccharide: pairs of monosaccarides
Complex Carbohydrates
* polysaccharides: chains of mono.
What are monosaccharides?
- glucose
- fuctose
- galactose
- all have the same number and kind of atoms, arranged in different ways
what is glucose?
- mildly sweet
- essential energy source
- one of the 2 sugars of every disaccharide
- polysaccharides are primarily made up of glucose
what is galactose?
- nto sweet
- usually a single sugar
- fermented milk products (yogurt and aged cheese)
- found in fermented products bc of the bacteria
- milk products, occurs as one of the two single sugars here
what is fructose?
- very sweet
- fruits and honey
- commerically: high fructose corn syrup (not natural, cornstarch and chemically treated)
What are the 3 disaccharides?
- lactose=glucose+galactose
- maltose=glucose+glucose
- sucrose=glucose+fructose
- joined together by condensation reactions
- split by hydrolysis reactions
what is lactose?
- milk sugar
- glucose + galactose
- principle carbohydrate of milk
- provides about 1/2 kcalorie in skim milk
what is maltose?
- 2 glucose units linked together
- produced during starch breakdown
- occurs during the process of alcohol fermentation
- only occurs in few foods (ex. barley)
what is sucrose?
- glucose + fructose
- sweetest of disaccharides
- occurs in fruits, veggies, and grains
- table sugar is sucrose refined from beets or sugarcane
- brown sugar is white sugar with molasses added
What happens when we eat a monosaccharide?
absorbed directly into blood
what happens when we eat a disaccharide?
- digested before absorption
- split into monosaccharides by enzymes
what is the most used nutrient in the body?
glucose
Where does the energy in fruit come from?
sugar
What are the polysaccharides?
- starch
- glycogen
- fibre
- made up of many strands of glucose units
- complex carbohydrates
What is starch?
- storage form of glucose in plants
- long chains of glucose molecules linked together
- branched: amylopectin
- unbranched: amylose
- digest starch to glucose (nutritive)
- rich food sources: grains, legumes, tubers
What is glycogen?
- storage form of glucose in animals
- high branched glucose chains–> allows for rapid hydrolysis
- stored in muscle (2/3) and liver (1/3)
- meat does not have a sig. amount of carbohydrates (glycogen is breaken down rapdily when slaughtered)
what is fibre?
- found in veggies, fruit, whole grains, legumes
- some provide support and structure to plant (leaves, stem, seeds)
- retain water (some)
- most are polysaccharides
- humans can’t break this apart, so most will pass through human body without providing energy, unless bacteria acts upon it in GI tract
What are prebiotics?
foods that are not digested (such as fibres) but promote bacterial growth by acting as food for the bacteria
What are soluble fibres?
- dissolve in water
- form gels (viscous)
- can be digested by bacteria in human colon
- sources: barley, legumes, oats, apples, citrus
- associated with lower risk of chronic disease: decrease cholesterol
- soften stool
- thickening reagent
- ex. they like to add this to salad dressing
what are insoluble fibres?
- do not dissolve in water
- outer layers of whole grains, strings of celery
- retain their structure
- not easily broken down
- ease pooping, helps with constipation (bc it goes right through)
- not easily fermented and don’t form gels
- cellulose
should you drink more water when consuming more soluble fibres?
yes because it holds onto water
How much of our kcalories does the DRI committe recommend come from carbohydrates?
45-65%
*should be complex carbohydrates, not refined sugars
Which contains fewer calories: carbohydrates or dietary fats?
carbohydrates
- carbohydrates (4kcal/g)
- dietary fats (9kcal/g)
what is high tryglceride linked to?
overuse of sugars may alter blood lipids in ways that increase cardiovascular risks through increased triglycerides
why are fibre rich foods recommended?
- supply vitamins, minerals, phytochemicals
- contain little or no fat
- lower energy gensity
- soluble fibres have sig. cholesterol lowering effects
- maintenance of healthy bowel function
- helps maintain healthy body weight
how does soluble fibre lower blood cholesterol?
- most of these foods are low in trans fats
- high in fibres, veggie prpoteins, phytochemicals
- can help carry out cholesterol: liver uses cholesterol to make bile, bile stored in galbladder, when fats are eaten bile is released (GO TO SLIDE 29)
Why are carbohydrates essential in blood glucose control?
- glucose absorption slows, helps steady levels of blood glucose and insulin
- lower glycemic index
What are 6 main reasons why there is a need for carbohhydrates?
- lower cholesterol and heart disease risk
- blood glucose control
- maintenance of digestive tract health
- constipation
- high fibre diets lower the rates of colon cancer relative to low fibre diets
- healthy weight management
What do foods rich in complex carbohydrates tend to be, and how is it beneficial?
- low in fats and added sugars
- promotes weight loss
What are the fibre recommendations and intakes for females agaed 19-50?
25 g/day
what is the fibre recommendations and intakes for males aged 19-50?
38 g/day
Can a diet have too much fibre? list some side effects
- purified fibre can lead to blocked intestine (if not enough fluid)
- binders in some fibres can act as chelating agents (could limit the absorption of iron, zinc, calcium)
- too much bulk can limit food intake and cause definciencies
- fibres remove water from body, lead to dehydration
What is bran?
- mainly made out of cellulose
- protects the grain
- generally removed in milling
what is endosperm?
- largelt starch grains embedded in a protein matrix
- endosperm is generally what is used in refined flour
what is germ?
- part where new grain develops
- majority of fat in the grains are located here
- often left out of processing to avoid rancidity
what does modern milling do?
- removes the germ and bran (causes whiter, smoother flour)
- increases starch content
- lowers fibre content
- white bread means loss of nutrients
What do carbohydrates need to be broken into in order to obtain glucose?
monosaccharides
Where does starch digestion begin?
in the mouth
where does starch digestion resume after the mouth? give some detail
- small intestine
- pancreatic enzymes split starch into smaller polysaccharides and disaccharides
- intestinal enzymes split these into monosaccharides
what is the difference between starch in refined grains and starch in things like cooked beans?
- refined grains: rapidly broken down to glucose
- cooked beans: digests more slowly and releases glucose later
What do resistant starch behave like?
fibre
What is sometimes classified as an insoluble fibre?
resistant starches
How are sugars digested and absorbed?
- split into monosaccharides before absorbed
- small polysaccharides and disaccharides are split by enzymes attached to the cells lining the small intestine (lactae, sucrase, maltase)
- once in bloodstream, travels to liver
What is commonly fermented by intestinal bacteria?
fibres
when increasing fibre how can gas production be minimized?
- starting with small servings
- gradually increasing serving size
Why do some people have trouble digesting milk?
- some people produce less lactase (ancestary)
- ability to produce lactase declines with age
- could be due to damage in intestinal villi
- lactose intolerance
What is often tolerated by people with lactose intolerance?
yogurt and aged cheese
how many cups of milk can be tolerated typically by a lactose intolerant person?
1-2 cups
what is a milk allergy
- allergic reaction to the protein in milk
- must find non dairy calcium sources (ex. orange juice)
How does a cell release energy from glucose?
glycolysis and krebs cycle
What is the minimum intake for carbohydrates as stated by the DRI?
- 130 g/ day
- this is to feed the brain and reduce ketosis
- more is recommended to maintain health and glycogen stores
What does the body use when there is a severe carbohydrate deficit?
protein to make glucose
*glucogenesis
This is an issue as it diverts protein from cricial functions of its own. carbohydrates have a protein sparing action (to prevent this from happening)
What happens if fat fragements were to combine together (not the compound derived from glucose)?
- would produce ketone bodies
- the accumulation of ketone bodies in the blood (ketosis) can disturn normal acid-base balance
What is a ketogenic diet used for?
used to reduce seizures in children and adults with servere refractory eplipsey
What happens when there is high blood glucose?
insulin is secreted from pancreas
What does insulin stimulate
- uptake of glucose into cells
- storage of glucose into glycogen
- excess glucose into fat
What happens when there is low blood glucose?
glucagon is secreted from pancreas
what does epinephrine do in times of danger?
breaks down liver glycogen as part of the body’s defense mechanism
what does glucagon stimulate?
breakdown of glycogen, therefore glucose is released into blood stream
what is the glycemic index (GI)?
a measure of the ability of a food to elevate blood glucose and insulin levels
* scored against the standard: usually white bread or glucose
what is glycemic load?
the glycemic index multipied by grams of carbohydrate
What is the glycemic index and glycemic load important for?
important to people with diabetes who must regulate their blood glucose
What is excess glucose stored as?
glycogen until the muscle and liver are full to capacity, if it’s filled, thnen could covert glucose to fat
what is type 1 diabetes?
- little or no pancreatic secretion of insulin
- often diagnosed in childhood
- less common, but on the rise
- leading chronic disease among children and young adults
Treatment:
* an external source of insulin
* meal planning to balance blood insulin, and glucose concentrations
what is type 2 diabetes?
- body produces insulin at first, then insulin resistance
- as blood glucose rises, so does blood insulin
- eventually, the pancreas may become less able to make insulin
- often diagnosed in adulthood
- most prominent type of diabetes
- if drugs are necessary: may stimulate insulin secretion, may improve tissue uptake of glucose, external source of insulin may also be used
Why do poeple with abesity require much more insulin for type 2 diabetes?
the more body fat, the more insulin resistant, the higher the blood glucose (impaired glucose tolerance is also possible)
what is impaired glucose tolerance?
blood glucose levels higher than normal but not high enough to be diagnosed as diabeted, sometimes called prediabetes (also includes impaired fasting glucose)
what is hypoglycemia? describe the two types.
- low blood glucose
- very rare in healthy people
- prevention: regularly timed, balanced, protein containing meals
postprandial hypoglycemica
* low blood glucose after a meal
* very rare, may occur after large weight loss
fasting hypoglycemia
* can be seen with cancer, pancreatic disease, diabetes, liver damage
What are some things to do when using artifical sweetners?
- moderation
- use does not automatically lower energy intake
- safer for teeth
- probably do not hinder weight loss efforts
what are sugar alcohols?
- do not contain ethonal or any other intoxicant
- provide energy
- produce a low glycemic resonse: body absorbs them slowly
- gas, abdominal discomfort, and diarrhea from large quantaties
- do not contribute to dental caries
- are polyols
- naturally found in small amounts in fruits and veggies
- manufactured from common sugars
- sugar substitute
What are the sugar alcohols?
- erythritol
- isomalt
- lactitol
- maltitol
- mannitol
- sorbitol
- xylitol
what are artifical/alternative sweetners?
- make food taste sweet
- do not promote tooth decay
- prodive very little food energy, if any at all
- can be toxic if consumed in high enough doses
what is saacharin?
- a zero kcalorie sweetner
- can be sold as a tabletop sweetner in canada
- not added to foods
what is cyclamate?
- a zero kcalorie sweetner
- can be sold as a table top sweetner in canada
- not added to foods
- heat stable
what is acesulfame-K (potassium)?
- a zero calorie sweetner
- 200x sweeter than sucrose
- holds up well during cooking
- excreted unchanged by the kidneys
what is sucralose?
- a zero calorie sweetner
- splenda
- 600x sweeter than sucrose
- useful in cooking, baking, tabletop sweetner
- only artifical sweetner made from sucrose
- passes through the body unchanged
what is aspartame?
- 200x sweeter than sucrose
- used in broad ranges of foods in canada
- not heat stable
- made of phenylalanine and aspartic acid and a methyl group
- in GI tract, it is split and absortbed normally
- in powder form, mixed with lactose often
- not safe for people with PKU (phenylkatonuria)
- metabolic by products include methyl alcohol, formaldehyde and diketoperazine (not toxic at generated levels)
what is PKU?
- phenylketonuria
- an hereditary inability to dispose of excess phenylananine
- this build up can cause irreversible, progressive damage if left untreated in early life
- newborns are tested for PKU (if positive, dietary measures need to be made)
what is stevia?
- 300x sweeter than sucrose
- naturally sweet herb
- a natural sweetner that was not approved for use in foods sold in canada until november 30th 2012
- sold in canada to consumers wishing to use this product for personal culinary use for a number of years
- approved by. health canada for use both as non medicinal ingredients, and as medicinal ingredients, in certain natural health products
When do the changes for labelling of sweetners (which ones?) and by when? Give an explanation of what will have to be done.
- by Jan 1 2026
- neotame, sucralose, aspartame, and acesulfame-potassium
- amount of sweetner will no longer appear on list of ingredients
- all sweetners used in foods will still apear on list of ingreidents on product label
- don’t have to be listed on front of the package anymore
- aspartame must still include a statement that will now appear in bold at the end of the list of ingredients (“Aspartame contains phenylalanine”)
what are strategies to keep in mind when using artifical/altervnative sweetners?
- moderation is the key
- use does not automatically lower energy intake
- probably do not hinder wieght loss efforts
- safer for the teeth
