Midterm 1 Flashcards
What is nutrition
The study of:
- the nutrients and other biologically active compounds in foods and in the body
- sometimes also human behaviours related to food
Diet
The food and beverages a person usually eats and drinks
Food
Any substance that the body can take in and assimilate that will enable it to stay alive and healthy
- carrier of nutrients
- our bodies break down food and absorb it ex. Sugars, carbs, fatty acids
Health
- the state of a human when it functions optimally without evidence of disease or abnormality
- optimal health can only be achieved when greater efforts are made in health promotion and prevention of illness and when nutrition is an integral part of these efforts
Ways to live longer and healthier
- exercise, diet, no smoking, no drinking
- good diet choices makes for a longer, healthier life
- having good genetics doesn’t mean you shouldn’t try and have a healthy lifestyle
Nutritional genomics
- the science of how nutrients affect the activities of genes and how genes affect the activity of nutrients
- not all diseases are equally influenced by diet, some are purely genetic
Nutrients
- components in food that are essential to the functioning of the body ex. Vitamins and minerals (carbs, protein, fat are also essential just not as much)
Energy providing nutrients
- carbs
- fat
- protein
Other nutrients
- water
- vitamins
- minerals
What do nutrients provide
- energy
- building material
- help maintain or repair the body and support growth
Essential nutrients
- the nutrients the body can’t make for itself from other raw materials (must come from food)
- “conditionally essential”= body can’t make enough of the required nutrient
8 essential amino acids
TV TILL PM
T- theronine
V- valine
T- tryptophan
I- Isoleucine
L- Leucine
L- Lysine
P- Phenylalanine
M- Methionine
Essential fatty acids
- Linoleic acid (fish oil)
- Linolenic
- 2 main fatty acids in canola
Vitamins
- 3 fat soluble (A, D, E)
- 1 conditional (K)
- all are water soluble
Essential minerals
All minerals are essential
Calorie values of energy-yielding nutrients
- carbohydrate: 4 cal/g (=kcal/g)
- protein: 4 cal/g
- fat (lipid): 9 cal/g
- alcohol: 7 cal/g (provides energy but is not a nutrient)
- food quantities measuring in grams
Calculating % calories from fat
- 14g protein, 5.5g fat, 17g CHO, 123 calories for 25 grams
5.5g fat x 9 calories/g = 49.5 calories
49.5 calories/123 calories x 100 = 40% calories from fat
17g CHO x 4 calories/g = 68 calories
68/123 x 100 = 55% calories from CHO
Calculating total calories
- 14g CHO, 1g protein, 3g fat, per 20g serving
Total calories:
(14g CHO x 4cal/g) + (1g protein x 4cal/g) + (3G fat x 9cal/g) = (56)+(4)+(27)
Total= 87 calories
Nutrient density
- most nutrients in relation to calories= dense
- way to assess which foods are the most nutritious
Ex. Calcium
- 1 c. Skim milk: 85 cal, 301mg calcium
- 1 c. Ice cream: 350 cal, 173mg calcium
- milk has more calcium per calorie, therefore. A higher nutrient density for calcium
Healthy diets
1) adequate- in essential nutrients, fibre and energy
2) balance- in nutrients and food types
- don’t only eat one thing all the time, no balance will leave you with a lack of essential nutrients
- east all the food groups
3) calorie control- foods provide proper amount of energy to maintain healthy body weight
4) moderation- in fat, salt, sugar, etc.
- processed food intake= semi-synthetic
5) variety- choose different foods each day
- goes hand in hand with balance
Food choices
- availability
- cost
- convenience
- emotional
- social
- cultural factors
- advertising
- habit
- personal preference
- genetic inheritance
- positive association
- health
Research designs
- case studies: individuals
- epidemiological study: populations
- intervention study: population with manipulation (controlled environment)
- laboratory study: tightly controlled conditions
Where do we get nutritional info from
Science-knowledge-recommendations
Hierarchy of evidence
Research views: (strongest) look at the body of literature and make conclusions based on a larger pool of evidence
- meta-analysis/ systematic views
Experimental research: (middle) may show causation, but only under some circumstances
- randomized controlled trials
Observational studies: (weak) shows correlations, so it gives us a broad view into a topic, but can’t prove causation
- cohort studies, case control studies, cross sectional studies
Case studies and reports (weakest)
Nutritional research
single studies must be replicated before findings become valid:
- can we trust the media?
- do not take actions based on the findings of single study
- science works by the accumulation of evidence and by consensus
- sometimes the media sensationalizes even confirmed findings
Nutritional genetics
How nutrients affect the activities of genes and how genes affect diet
Methods for food intake
1) diet recall (24-hr recall)
- advantage= easy for client
- disadvantage= relies on memory, day may not be typical, client may not be truthful
2) diet record (3-5 days)
- advantage= does not rely on memory, written down and assessed immediately
- disadvantage= high burden, client may change eating habits because of recording
Methods for food intake
Food frequency questionnaire
- advantage= easy, quick to complete
- disadvantage= may not include all foods eaten, some clients have difficulty figuring out where they fit in a range, intake may vary day to day
- targeted at different nutrients
Dietary quirkiness and nutrition objectives
- helps guide people in what to eat to stay healthy
- dietary reference intakes (minimal amount of nutrients you need in your diet to have optimal health
Interpretation of food take
Compare the average daily intake to at least 2 of 3 guidelines:
- eating well with Canada’s food guide
- Canadian nutrients recommendations
NOTE: influence of season, cost, convenience, cultural and regional foods, etc.
Dietary reference intakes (DRIs)
- developed jointly by Canada and USA as nutrient standards
The DRI committee has set values for: - vitamins
- minerals
- carbs
- lipids (fats)
- protein
- fibre
- water
- energy
DRI goals
For each nutrient, the DRI establish several values, each serving a different purpose
Goals:
- set intake goals for individuals
- assess intakes, plan diets (aid dietitians work)
- facilitate nutrition policy and research
- establish safety guidelines
- prevent chronic disease
DRI terms
- RDA (recommended dietary allowances): intake goals for individuals
- EAR (estimates average requirements): intake goals for given stages of life and gender groups
- AI (adequate intakes): goals for individuals when insufficient scientific data for setting RDA
- UL (tolerable upper intake levels): maximum amount that is safe (can’t take more than this, its not healthy)
- ADMR (acceptable macronutrient distribution range): range of intake for energy containing nutrients
ADMR
- carbs (adults 45-65% daily calories)
- fat (adults 20-35% daily calories)
- protein (adults 10-35% daily calories)
Factors considered for DRIs
- BMI: reference weight and height
- Age: to account for physiological changes of lifecycle
- Time: not based on 1 day of food intake, rather an average consumption
factors not considered for DRIs
- activity: elite athletes vs inactive
- diet: vegans vs omnivores
- Geographic areas: southern vs northern Canada for vitamin D from sunlight
- Lifestyle: smoking increases vitamin C requirement
- Illness, malnutrition
proper use of DRI
- most nutrients (except energy): mean +2 standard deviations
- The DRI RDA meets the nutritional needs of 97.5% of the population
- the RDA exceeds the requirement of most individuals in the population (all except 2.5%)
- energy recommendations set at the mean (50%): an average requirement based on the reference height and weight
Naive vs accurate view of DRIs
Naive thinks if you eat more than the recommended food levels you are out of the danger zone and in the safe zone but there is also such thing as toxicity which is when you enter a danger zone from eating too much
Nutrition labeling
Nutrition facts box components:
- specified quantity of food
- actual amount of calories and 12 nutrients
- % daily value
Serving size
- specific amount of food listed under the “nutrition facts” title
- all nutrient information is based on this amount of food
- listed in common measures you use at home
% DV
- can make it easier to compare foods
- <5% DV, little of the nutrient (bad source)
- > 15% DV, a lot of the nutrient (good source)
Diet health related claims
- A diet low in sodium and high is potassium, and the reduction risk of hypertension (high sodium= hypertension)
- A diet adequate in calcium and vitamin D, and the reduction of risk of osteoporosis
- A diet low in saturated fat and trans fat, and the reduction of risk of heart disease
- A diet rich in vegetables and fruits, and the reduction of risk of some types of cancer
- Minimal fermentable carbs in gum, hard candy or breath-freshening products, and the reduction of risk and dental caries
Phytochemicals
- non nutrient compounds derived from plants
- have biological activity in the body
- functional foods: similar to conventional foods (consumed as part of usual diet)
- potential breast cancer
- flavonoids (could lead to cancer)
Phytochemicals in pills
- alter body functions, sometimes powerfully, in ways only partly understood
- lack of safety evidence for isolated Phytochemicals in humans
Phytochemicals from food
- food, not supplements, is the most effective and safest source of Phytochemicals
Functional foods:
- make the line between what is a food and what is a drug blurry
- mainly occur in nature
Nutraceuticals
Supplements
- lack of safety evidence for isolated Phytochemicals in humans
- genistein (from soybeans) increases cancer in lab animals
- food>suppliments
