Nutrition Review Midterm (1)
Nutrition: is the science that studies food and how food nourishes our bodies and
influences our health.
Why we eat the foods we do:
• culture, religion, beliefs/values, social, convenience, advertising, economy,
emotional comfort, habit, personal preference, positive associations,
weight/body image, nutritional value, appetite, hunger.
Appetite: The psychological desire to eat specific foods. Pleasant sensations
associated with food, influenced by:
• psychological factors, brain compounds, inborn appetites, some health
Hunger: The physiological sensation in response to a need for food. Unpleasant/
negative sensation. Hunger is influenced by:
• brain (hypothalamus), amount and type of food we eat, blood glucose
levels, exercise, hormones.
>hormones: neuropeptide Y hunger UP
leptin fullness UP
A Nutritious Diet:
• provides proper combo of nutrients and energy
• Nutrients: are chemicals found in foods. They are critical to human growth
◦ Nutrients include:
-carbohydrate, fat, protein (macronutrients- energy containing)
-vitamins, minerals (micronutrients- do not contain or produce energy)
-the amount of energy in food that can be supplied to the body
-measured in kilocalories (kcals, calories)
-obtained from energy-containing macronutrients
-carbohydrate (4 kcals/g), fat (9 kcals/g), protein (4 kcals/g)
• is adequate, moderate, varied, balanced
◦ adequate: if it provides enough energy, nutrients, and fibre to maintain
health. May be adequate in one area but not in another.
◦ Moderate: if we consume the right amounts. Moderation relates to
portion size and frequency, for example consumption of alcohol.
◦ Varied: if we consume a variety of different foods each day.
◦ Balanced: if we consume combinations of foods providing proper balance
of nutrients. Even if your diet is adequate in meats, it's not balanced
unless it is also adequate in veggies. Health: a state of complete physical, mental and social well-being and not merely
the absence of disease or infirmity. Includes physical activity and occupational,
social, emotional, intellectual and spiritual health.
Dietary Reference Intakes (DRI)
DRIs for most nutrients DRIs for energy and
Estimated Recommended Adequate Tolerable Estimated
average dietary intake upper intake energy
requirement allowance (AI) level requirement
(EAR) (RDA) (UL) (EER)
(EAR): represents the average daily nutrient intake level that meets the
requirements of half the healthy individuals in a given group.
(RDA): average daily nutrient intake level that meets nutrient requirements.
(AI): based on educated guesswork, AI is a recommended average nutrient intake
level based on observed or experimentally determined estimates of intake by a
group of healthy people. Not based on EAR.
(UL): highest average nutrient intake level likely to pose no risk of adverse health
effects to almost all individuals in a particular stage and gender group.
(EER): average dietary intake predicted to maintain energy balance in healthy
(AMDR): is defined as a range of intakes for a particular energy source that is
associated with reduced risk of chronic disease while providing adequate intakes
of essential nutrients. An AMDR is expressed as a percentage of total energy
-can turn into skeletal fluorosis
-caused from too much fluoride intake
-teeth can only be bleached to fix outer appearance, however the problems lie
-makes bones brittle
Three Main purposes of food labels:
1. Basic product information • ingredients, product weight, net quantity, expiry date, grade or quality,
country of origin, manufacturer, importer.
2. Health safety and nutrition info
• amounts and types of fats, proteins, carbohydrates, vitamins, minerals,
in a specified serving size.
3. Provide a means for marketing or promoting product by label claims
• “low fat” “cholesterol free” “high source of fibre” etc.
Main Components of a food label:
1. ingredient list 2. nutrition facts table (1+2=mandatory)
3. nutrient claims 4. health claims (3+4=optional)
The 13 core nutrients are:
• fat, saturated fat, trans fat, cholesterol, sodium, carbohydrate, fiber, sugar,
protein, vitamin A, vitamin C, calcium, iron.
• Because of their health professional and scientist-driven choices.
To read and use nutrition facts table:
1. serving size
3. % daily value
% Daily Value:
• how much a serving contributes to your overall intake of various nutrients
• amounts of fats, sodium, carbohydrate and fibre in 1 serving listed in 1 g or
mg, AND %DV
• based on recommendations for 2000 kcal diet
• foods with <5% DV are low in that nutrient
• foods with >20% DV are high in that nutrient
Nutrient content claims: claims made about a nutrient in a food. “free” “more”
“reduced” “source of” “light/ lite” (light is meaningless)
• low fat = reduced risk of heart disease
• low salt, high potassium= reduce risk of high blood pressure
• adequate calcium and vitamin D= reduce risk of osteoporosis
• variety of fruit and veggies= reduce risk of certain cancers
Digestion: process by which foods are broken down, either mechanically or
Absorption: process of taking products of digestion from gastrointestinal (GI) tract
into the bloodstream or lymph system.
Elimination: process by which undigested and unabsorbed products of food and
waste products are removed from the body. Digestion begins in the mouth:
• chewing initiates mechanical digestion
◦ breaks down food into smaller components, mixes nutrients together
• saliva moistens food and initiates chemical digestion
◦ salivary amylase starts carbohydrate digestion
• products of this digestion moves down esophagus with help of peristalsis
Peristalsis: squeezing and pushing contractions that move food in one direction
through the GI tract (much like a snake eating)
*stomach has strongest muscles of the digestive tract
*protein digestion is one of the stomach's main functions
chyme: unrecognizable mush at the bottom of the stomach
Role of the Stomach:
• mixes, digests, and holds food
• secretes gastric juice
◦ hydrochloric acid ( activates pepsin )
◦ gastric lipase ( begins chemical digestion of dietary fat )
◦ mucus ( protects stomach