NFS284 Test 1

Human nutrition

The study of interactions between human health and food

Canadian Healthy Eating Index (CHEI)

Measures adherence to Canada's food guide, get points for following and lose points for not, perfect score=100, worst scores in adolescence, gets better with age, best in childhood when food is mainly under parental control

Essential nutrients

Nutrients necessary for normal body functioning that must be provided by diet because the body cannot synthesize them in sufficient quantities, if absent then see deficiency symptoms/illness and possibly death

Macronutrients

Nutrients required in large amounts, are carbohydrates, lipids and protein

Amino acids

Building blocks of proteins

Energy sources

Fat and carbohydrates used to support metabolism and physical activity, protein will also be used if present in excess

Kcal content of macronutrients

Carbs= 4 kcal/g

Fat= 9 kcal/g

Protein= 4 kcal/g

*Alcohol = 7kcal/g

Starch

Digestible carbohydrate energy source found in staple foods like rice, wheat, corn, potato and cassava

Triglycerides

Major chemical form of lipids in food, is an ester of glycerol and three fatty acids

Polyunsaturated fatty acid

Fatty acid with one or more double bonds, beneficial to health, include canola and soybean oil

Monounsaturated fatty acid

Fatty acid with one double bond, include oleic acid and olive oil

oleic acid = olive oil

Essential fatty acids

Linoleic acid and alpha-linolenic acid, are both polyunsaturated fatty acids

Linoleic acid

Aka omega 6, an essential fatty acid easy to obtain and synthesize

Alpha-linolenic acid

Aka omega 3, an essential fatty acid that must be obtained from diet, major source is flax seed oil

Long chain omega 3 fatty acids

Eicosapentaenoic acid (EPA) and docasahexanoic acid (DHA), omega 3 fatty acids synthesized in the body from alpha-linolenic acid and found in fatty fish and fish oil supplements, not considered essential because can be biosynthesized

-lower risk of diseases

Saturated fats

Fats solid at room temperature, derived from animal products, fatty acid associated with increased risk of disease

Trans fats

-Fats made from hydrogenation of plant-based oils (chemically modified to be in different chemical position)

Ex. margarines, shortening

-fatty acid associated with increased risk of disease (body doesnt know what to do with them)

-now have been banned from food supply in US and Canada

Dietary fibre

Indigestible carbohydrate fermented by microflora of large intestine, limited source of energy, found in whole grains and legumes

Glucose

monosaccaride (carb) circulates blood

-energy source for brain

-want slow consistent amount to brain

Sucrose

Disaccharide of fructose and glucose, made from sugar cane, linked to obesity

High fructose corn syrup

1:1 mixture of fructose and glucose, linked to obesity

Micronutrients

Essential nutrients needed in small amounts, are vitamins and minerals

Vitamins

Organic micronutrients required for metabolic processes

Fat soluble vitamins

Vitamins that can be stored in liver and adipose tissue

-not rapidly depleted

-high intake can be toxic

-vitamins A, D, E and K

*more at risk of disease

Water soluble vitamins

Vitamins not stored in the body, are rapidly depleted (except B12)

-so need to be regularly consumed

-high intake is excreted in urine

-vitamins B and C

*High risk of deficiency

Calcium

Mineral important for bone health

-present in largest amounts in bone

-not the only one responsible for tensile strength

Sodium

Mineral widely used in processed foods, overconsumption can increase blood pressure (draw fluid into BV --> + BP)

Iron

Mineral that if insufficient amounts are consumed can lead to anemia

3 types of nutritional anemia

1. Fe

2. B-12

3. Folate (irradiated in Canada)

Iodine

Mineral that if insufficient amounts are consumed can lead to a goitre(swelling of thyroid gland)

-source = ocean

-eat less processed foods (high in non-iodized salts), and use more iodized salt at home

Undernutrition

Lack of macronutrients and caloric intake

Overnutrition

Excess of macronutrients and caloric intake

-most likely micronutrient deficiencies

Nutrigenomics

Study of the interaction between genetic variance (predisposition to develop nutritional related conditions) and nutrition & lifestyle

-helps develop personalized medicine by recognizing genetic variation causes differences in nutrient absorption

Adequacy

Consuming enough of a nutrient to maintain health

Nutrient density

Measure of nutrient levels per kcal

Basic principles of a healthy diet

Eat variety of foods, balanced diet, everything in moderation, avoid excess kcal intake (keep calorie intake appropriate to age, gender, PA)

Portion distortion

Supersizing of portions seen to have occurred through time, based on inference of value (bigger seems better), society has gotten used to larger portion sizes so overconsumption and obesity has risen

Subpackaging

Packaging food into 100 kcal portions

Functional foods

Foods providing health benefits beyond basic nutrition

Phytochemicals

Biologically active non-nutrients found in plant foods, are health-promoting

Antioxidants

Substances that neutralize reactive O2 species to reduce oxidative damage

Cartenoids

Phytochemicals with antioxidant properties, decreases risk of cancer, CV disease and eye diseases, gives yellow-orange colour to carrots, yams, apricots and mangos

Beta-carotene

Cartenoid vitamin A source

Lypocene

Cartenoid antioxidant

Beta-cryptoxanthin, lutein and zeaxanthin

Cartenoids that decrease risk of macular degeneration in retina

Flavonoids

Strong antioxidants that protect against cancer and CV disease, found in citrus fruits, veggies, grapes, chocolate and tea

Anthocyanidins

Flavenoids giving blue and red colour to blueberries, raspberries and red cabbage

Indoles

Sulphur-containing phytochemical that stimulates carcinogen-detoxifying enzymes to inactivate excess estrogen, found in cruciferous vegetables

Alliums

Sulphur-containing phytochemical that stimulates carcinogen-detoxifying enzymes to lower cholesterol, blood pressure and platelet activity, found in cruciferous vegetables

Plant hormones

chemical messengers in plants that effects human health

Phytoestrogens

Plant hormones that halt cancer development by interfering with estrogen, have similar structure to estrogen so block receptors

Zoochemicals

Health promoting substances in animal foods

Phytochemical-rich diet

Colourful fruits and veggies, spices, whole grains, plant proteins, nuts

Canada's food guide

Guideline developed to describe a diet beneficial for health to help Canadians make healthy food decisions

Canada's food guide groups

Fruits and vegetables, grain products, milk and alternatives, meat and alternatives

CFG recommendations with fats and oils

Low intake of trans and saturated fat, high intake of unsaturated fat to get adequate intake of essential fatty acids and decrease CV disease risk

Ways to assess nutrients

1. Nutrient-based approach looking at individual nutrients and their amounts required

-lab-based

2. Food-based approach looking at dietary patterns and types/amounts of food needed to maintain health

-maximizing probability to meet individual nutrient needs by following pattern of food intake

How often are recommendations regulated?

regularly. merp.

Nutrition recommendation for Canadian diet

DRIs > RNI

Recommended nutrient intake (RNI)

First recommendations in Canada, established in 1930's and 40's

-nutrient based approach

Dietary reference intakes (DRIs)

Set of nutritional references determined by the Institute of Medicine (IOM) in Canada and US

-replaced RNIs -->umbrella term of dietary recommendations

-used for planning and assessing diets of healthy individuals, includes information for all ages and sexes

Food-based approach

Ex. have certain amounts of food groups per day.

Which part of animal has highest mineral density?

organ meat

-especially Vitamin B-12

-around WW11, no part of animal wasted, but now we throw away parts of meat. Culture is now wateful and picky

Shaded area under curve

Probability of adequate or inadequate nutrient intake

Estimated average requirements (EARs)

Nutrient intake that meets the requirement of 50% of individuals in a group, used primarily for vitamins and minerals, estimates probability that an individual is meeting their requirement

Determining EARs

First find biochemical criterion that lets you determine intake at which an individual's requirement is being met by doing a depletion-repletion experiment on healthy adults, then determine requirement distribution from a sample population

Depletion-repletion experiment

Start with depletion: feed participants vit-X (one of interest) free diet, track levels of vit-X in blood until at zero, indicating depletion

repletion: begin re-feeding vit-X and see what happens to blood levels, intake that stops corresponding rise in blood levels is level of saturation of vit-X, this is their intake requirement because anything above that level is useless

Saturation

Intake of a vitamin or nutrient at after which levels in blood will not change, is the individual's requirement

EAR distributions

Bell-shaped normal distribution, 50% of population will be getting their adequate intake at the mean/median (EAR)

Nutrient requirement

Experimentally determined requirement for a nutrient to maintain health, varies between individuals

Nutrient intake

Amount of nutrient consumed determined by composition of the diet

Meeting an EAR

Means you have a 50% chance of meeting your personal daily requirement

Recommended dietary allowance (RDA)

Intake that ensures a 98% probability of meeting your requirement, is EAR+2SDs, is a good goal for an individual because it is almost certainly adequate

EAR cut point method

Assessment used to determine the proportion of a population meeting its intake requirement, shows how the population is doing as a whole, collect data using a national survey and plot results on an intake distribution

Intake distribution

Plot of intakes of a specific nutrient consumed in a population, the proportion of the population with an intake less than the EAR is the proportion of the population not meeting their requirement, if its 10% or less then the population as a whole can be said to have an adequate intake

Adequate intake (AI)

Used when insufficient data to calculate EAR, is based usually on the estimate of average nutrient intake of a healthy population, used often for children because hard to collect data, is a good personal intake target

Tolerable upper intake level (UL)

Highest level of habitual nutrient intake that is unlikely to pose a risk of adverse effects, is NOT a recommended level of intake because there is no benefits above RDA, came about because supplements can raise intake too much

Energy balance

Energy consumed = energy expended

Positive energy balance

Energy consumed > energy expanded

Negative energy balance

Energy consumed < energy expanded

Estimated energy requirement (EER)

Experimentally determined equations used to estimate average energy need of adults, variables include sex, age, physical activity and height

Sedentary lifestle

Activities of daily living, less than 30 min intentional exercise per day

Low active lifestyle

Walking 30 mins ar 6.5 km/hr per day, uses 135-165 kcal

Active lifestyle

Walking 1 hr 45 mins at 6.5 km/her per day, uses 470-580 kcal

Very active lifestyle

Walking 4 hrs 15 mins at 6.5 km/hr per day, 1145-1405 kcal

How to lose weight

Burn more calories than you consume, takes a lot of activity to expend a lot of calories

Variables that increase EER

Male, young, higher BMI

Weight change curve

When first starting to lose weight it happens quickly because your caloric requirement is higher so not too hard to be under it, but over time your energy requirement decreases with weight loss so becomes easy to reach a plateau

Acceptable macronutrient distribution range (AMDR)

Range of percentage of daily calories should come from each of the macronutrients

Carbs= 45-65%

Fat= 20-35% (

Development of 2007 CFG

Looked at the current CFG of the time and made 500 menus conforming to it, tested if there is a 90% probability that nutrient requirements were being met, saw some problems around adequate vit A intake so decided to revise

Criticisms of CFG

Not enough emphasis on reducing sugar intake, emphasis should be on reduction of saturated fats not fat in general, should promote plant-based proteins more

Canadian's sugar intake

Most is natural from fruit but not far behind is added empty calories from soft drinks, white and brown sugar, milk, juice, candy, etc, 37.9% of main sources are empty calories, there is no recommended daily allowance of sugar

Empty calorie sources

Foods with a low nutrient density per calorie

Scientific evidence of sugar

None saying it is beneficial, all research shows either no effect or adverse effect like weight gain, increased risk of type 2 diabetes, hypertension and CV disease

Sugar controversy

Debate whether it is intrinsically harmful because of metabolic reasons (altering liver function) or because it facilitates overconsumption of kcals, particularly when drinking empty calories

Canadian's fat intake

28.1% from fast food sources

Fat nutrient density

Very high in kcals, so a low fat diet does not necessarily mean a low kcal diet

Scientific evidence of fat

Saturated fat linked to increased risk of CV disease and polyunsaturated fat linked to a decrease risk

Recent controversy around saturated fat evidence

Studies showed that with decreasing saturated fat intake people still had same CV risk so many started believing saturated fat was not a risk factor, but a good explanation is that CV disease risk depended on replacement of saturated fat in diet, if replaced with more carbs then risk is the same but if replaced with polyunsaturated fat then reduced risk

CV disease risks

#1 is cancer, but everything else is things that could be made worse/created by too much saturated fat, like high LDL, obesity, low dietary omega 3, high bp