*KNES 237 MIDTERM 2

what are the two classes of carbohydrates?

simple and complex

what are the two simple carbohydrates?

monosaccharides and disaccharides

monosaccharides

glucose (blood sugar or dextrose, most abundant), fructose (fruit sugar), galactose (milk), absorbed into bloodstream

disaccharides

two monosaccharides joined by a covalent bond
sucrose (glucose + fructose)
maltose (glucose+glucose)
lactose (glucose+galactose)

what is the most widely used natural sweetener?

sucrose

maltose

formed from the partial breakdown of starch and often used in malt beverages (glucose + glucose)

lactose

milk sugar, one of the only animal sugars besides glucose (glucose + galactose)

what are the 3 primary nutritional polysaccharides?

glycogen (storage form of glucose)
starch (energy storage in plants)
cellulose (plant structure, non-digestible)

how are starch and glycogen bonded?

with alpha glycosidic bonds, can be broken down by enzymes

how is cellulose bonded?

with beta glycosidic bonds, and can not be broken down by amylase

oligosaccharides

short chains (most ~3) of monosaccharides joined by bonds that cannot be broken by human enzymes (fibre), fructans and galacto-oligosaccharides

examples of oligosaccharide foods

garlic
onions
wheat
inulin
artichokes
beans
lentils
chickpeas

polysaccharides

long chains of monosaccharides joined by bonds (some digestible and some not) include glycogen, starch, and cellulose

examples of polysaccharide foods

potatoes
bread
pasta
rice
corn
cereal
apple peel, seeds, nuts (contain cellulose)

fiber in the intestine

in the colon, bacterial enzymes break down fiber to form short chain fatty acids and gas as a byproduct, and it feeds our gut microbiota

5 effects of gut microbiota in health

- harvest energy from otherwise indigestible foods
- production of certain vitamins (K, B)
- suppress the growth of pathogenic bacteria
- trains the immune system
- proper digestive function

what does the grain-gut axis affect?

anxiety, depression, autism

what does the microbiota-liver axis affect?

obesity, type 2 diabetes, fatty liver disease

what are two types of intestinal disease?

crohn's disease, ulcerative colitis

what is an example of a pathogen in the gut microbiota?

clostridium difficile

what foods support microbiota symbiosis?

high fiber whole natural foods

what foods support microbiota dysbiosis?

processed foods low fiber

what are 4 parts of whole grains?

outer bran layer
germ
endosperm

outer bran layer of whole grain

rich source of dietary fiber

what does the germ of a whole grain contain?

protein
unsaturated fats
thiamin
niacin
riboflavin
iron
other nutrients

what parts of whole grains are removed in the refining process?

germ and bran

what is in the endosperm of whole grain?

primarily starch

what does soluble fiber do?

slows down glucose absorption, there by lowering peak blood glucose levels, and reduces fat and cholesterol absorption

what foods is soluble fiber found in?

oats
barley
fruit pulp
peas
beans
citrus fruits
strawberries
psyllium

how do soluble fiber calories compare to digestible carbohydrates?

digesting 1g/starch = 4kcal
digesting 1g/oat fibre = 1-2kcal
more fiber = less calories

how does insoluble fiber benefit health?

moves bulk through gut, controls gut pH, removes toxic waste, prevents constipation

in what foods is insoluble fiber found in?

vegetables, wheat bran, whole grains, flax seed, popcorn (hulls), corn bran, seeds, nuts, apple peel

how does the body manage glucose? (7 steps)

1. blood glucose rises when you eat
2. high blood glucose stimulates pancreas to release insulin
3. insulin stimulates uptake of glucose into cells and storage as glycogen in liver and muscle. it also helps convert excess glucose into fat stores
4. as body cells use glucose, blood levels decline
5. low blood glucose stimulates pancreas to release glucagon
6. glucagon stimulates liver cells to break down glycogen and release glucose into blood
7. blood glucose begins to rise

added sugars

major sources of simple sugars in most diets are added during processing of food, labels contain total sugar information per serving bu two not distinguish between naturally occurring and added sugars yet
added sugars add calories without adding nutrients
all simple sugars

how are sugars shown on food labels?

sugars are grouped together
when something is processed, the % daily value increases (ex. milk = 13%, chocolate milk = 26%, usually >15% of daily value when sugar is added)

what are three bad sides of sugar?

- tooth decay
- empty calories (calories without nutrients)
- often mixed with fats in sweets (replace sweet/sticky foods with fruits and veggies, overall diet quality decreases when sugar increases)

sugar alternatives

alcohol sugars: xylitol, mannitol, sorbitol (alcohol -itol not absorbed by the body

what are some characteristics of sugar alternatives?

used in chewing gum/candy/food, can be used to mask the unpleasant aftertaste of some artificial sweeteners, are not well absorbed in the gut, large amounts can cause diarrhea

stevia

a herbal sugar alternative, GRAS, approved in 2012

what did studies with crude whole leaf extracts of stevia show?

reproductive, renal, and cardiovascular toxicity, but purified stevioside preparations show no toxic effects

what are 5 artificial sweeteners?

cyclamate
aspartame
sucralose
acesfulfame K (suzette)
saccharin

cyclamate

first commercial artificial sweetener
banned in the late 60s
banned in the US but approved for use in Canada

aspartame

a dipeptide (amino acids, can be digested)
not compatible with high temperatures
must beat a "contains phenylalanine" label (can be dangerous for PKU, an inherited disorder where you cannot metbolize it
"nutrasweet" & "equal"
acceptable daily intake 40mg/kg BW

sucralose

chlorinated sugar (body can't digest)
60x sweeter than sugar
"splenda"

acesulfame K (sunette)

often used in combination with other artificial sweeteners to mask the aftertaste (aspartame)

saccharin

developed in 1879 by accident
300x sweeter than sugar (sucrose)
banned in 1997 due to bladder cancer fears (high concentrations) but returned to market
"hermesetas" available from pharmacies in Canada

how is sugar a mechanism for tooth decay?

sugar is food for bacteria, and produces acid which erodes enamel
bacterial form sticky white plaque (pre-determinant for cavities)

how long after eating sugar is acid produced?

20 minutes

what are promoters of tooth decay?

increased frequency of sticky foods
acidic beverages
excessive cleaning/polishing of teeth
nursing bottle syndrome

nursing bottle syndrome

only babies/children still using a bottle can get it
putting the baby to bed with a bottle in their mouth creates an environment that promotes tooth decay, bathing the teeth in lactose

what are some protective foods against tooth decay?

cheese - increases pH of plaque
protein - calcium strengthens enamel
low calorie sweeteners (sorbitol, mannitol, xylitol) - stimulate salive

how do fluoride and dental health affect tooth decay?

promote remineralization of eroded enamel
water, toothpastes, dental rinses

what can excess fluoride do?

leads to fluorosis or "mottled" enamel during tooth development

what is the effect of fluoride in the water source?

calgary removed it in 2011, but edmonton and calgary had high rates of tooth decay but it was increasing more rapidly in calgary

what are the 3 types of diabetes?

type 1, type 2, gestational

gestational diabetes

only during pregnancy - goes away once they've had the baby, insulin-resistant

type 1 diabetes

insulin dependent
begins before 40
treatment with insulin injections, diet and exercise

type 2 diabetes

non insulin dependent
lifestyle
treatment is weight reduction - can improve blood glucose control

poorly controlled, untreated diabetes produces what symptoms?

blurred vision
frequent urination (kidneys trying to dilute glucose)
weight loss (type 1)
increased susceptibility to infection
slow healing sores
extreme hunger and thirst

what are some long term consequences of diabetes?

heart disease and stoke
kidney damage (nephropathy)
blineness (retinopathy)
nerve damage (neuropathy) - the leading reason for amputation in NA
loss of limbs due to poor circulation - compromised blood vessels
alzheimer's disease

insulin

a pancreatic hormone that reduces blood glucose by facilitating passage of glucose into cells

what does low/no insulin do?

starves cells, or if cell membranes become insulin resistant

how many women develop gestational diabetes?

5-6%

what groups of women have greater risk of gestational diabetes?

indigenous
african americans
women with obesity
women over 35
women with low PA

what happens to the baby with gestational diabetes?

macrosomia (large baby more than 4kg/8lb13oz)
high blood glucose levels in mother brings extra glucose to baby, causes baby to put on extra weight, increases the risk of baby having diabetes later in life

what occurs after delivery in gestational diabetes?

infants may be overly fat and have blood glucose control problems, and higher risk of diabetes later in life for mother and child, 6-20% of children will have a physical abnormality that may threaten survival or a high quality of life (cleft palate, club foot, heart defects)

which type of diabetes is the most severe

type 1

what percentage of all diabetes is type 1?

5-10% and is increasing yearly (2x as high as children in 80's)

at what age does diagnosis of type 1 diabetes peak?

11-12 years, usually before age 40

where was insulin discovered?

U of T

why is type 1 diabetes autoimmune?

destroys the part of the pancreas (beta cells) that produce insulin

what protects against type 1 diabetes?

breastfeeding for the first four months (oligosaccharides in breast milk feed gut microbiota)

what are some environmental factors that affect type 1 diabetes?

cow's milk proteins
vitamin d deficiency
early exposure to gluten
certain viruses
gut microbiota
don't know the definitive trigger

in what type of diabetes are environmental/genetic factors more important?

type 1 - environmental factors
type 2 - genetic factors

how is type 1 diabetes managed?

insulin (injections, pump, islet transplant)
diet
exercise

what percentage of diabetes is type 2?

~90%

what ages is type 2 diabetes present?

most common in people over 40, but as young as 8, increasingly common in children and adolescents

what are some risk factors for type 2 diabetes?

obesity, sedentary lifestyle
associated with apple obesity
runs in families (black, hispanic, indigenous and asian-americans

how many classes of diabetes medications are there?

8

what is used to diagnose T2D?

elevated fasting blood glucose levels below the cut-off point

prediabetes

a major risk factor for T2D, 20% of Canadian adults and 314 million people worldwide

what are common risk factors for insulin resistance?

obesity
low levels of physical activity
genetics

insulin resistance

when blood glucose levels become high, the pancreas secretes more insulin to keep glucose levels under control, pancreas become exhausted from over-work and insulin production slows or stops

how do we know if type 2 diabetes is underway?

when fasting blood glucose levels reach 7mmol/L or higher

what is in a proper diet to manage T2D?

complex carbohydrates - whole grains, high fiber foods, veggies, fruits, low-fat milk, meat and fish
unsaturated fats
regular meals and snacks
protein at every meal (particularly bedtime)

does sugar intake cause diabetes?

no, unless it contributes to obesity

how should sugar intake be changed in individuals with diabetes

doesn't have to be eliminated, but total carbs should be reduced

what do high-sugar diets do?

increase blood triglyceride levels and the risk of heart disease in people with metabolic symdrome

glycemic index

ranks carbohydrates by how much they spike blood glucose, foods that elevate glucose require more insulin to move glucose into cells
blood glucose elevation caused by 50g/food compared to elevation caused by 50g/glucose

What do low glycemic index foods do?

decrease triglyceride levels and insulin needs in T2D

what are some examples of foods in the glycemic index

glucose>sticky rice>white rice>brown rice>yogurt>milk>hummus

alcohol is...

both a food (carbohydrate) and a drug (modifies various body functions

what is 1 standard drink?

1 mixed drink with 1.5fl oz (44mL) of 80-proof liquor
5fl oz (148mL) wine
12 fl oz (355mL) or beer/wine cooler

what is a standard number of alcoholic drinks/day?

women - 1, men - 2

what are positives of alcohol consumption?

may protect from heart disease in men over 45 and women over 55
increases HDL (red wine)
may protect against T2D in non diabetics and ischemic stroke (not hemorrhagic)
may decrease the ability of LDL cholesterol to stick to plaques in arteries

what do red wine's pigments do?

act as an antioxidant and inhibit blood clot formation (purple grape juice also works)

heavy drinking

~5 or more drinks/day threatens drinkers' health and those of others as well

alcoholism

chronic and progressive disease

alcohol poisoning

passing out
semi-conscious
cold, pale, or bluish skin
vomiting while sleeping
slow or irregular breathing
seizures

what percentage of Canadians drink much more than is healthy?

20%