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Kinesiology 110

Human Nutrition :

Current IssuesInstructor : Ryan Dill

email ryand@sfu.ca

778-782-7851 (Vancouver)

Office HC 2622 (ring doorbell at 2600)

Office hours : Mondays 3-4 pm

Also by appointment through email

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Course Tools• Course Web Site • www.sfu.ca/~ryand/kin110.htm• Course outline• Grading system • Download Assignments• Lecture Schedule

– Download Course notes • Link to web site for Text book

– Multiple choice quizzes– Nutrition Crossword puzzles

– Animation tools

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Nutrients and Nourishment

Chapter 1

Chapter 2 p 31-72

Appendix D

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• Lecture Outline– Why do we eat the way we do?– Overview of the Study of Nutrition– Nutrients and their roles in the body– Scientific process in Nutrition

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Why do we eat the way we do?

• Sensory– Flavour (taste and smell), texture, appearance

• Cognitive– Learned food habits (early experiences with food)– Social factors - time crunch versus relaxing experience– emotional needs– Nutrition and health beliefs– advertising

• Environmental– Economic, lifestyle, cultural factors, religious beliefs

• Health– Physical restrictions due to disease– Declining taste sensitivity– Age and gender

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What drives us to eat?• A complexity of factors influence eating• Hunger - physiological drive to find and eat food

• Appetite - primarily psychological influences encouraging us to find and eat food - often in absence of hunger

• Satiety - state in which there is no longer a desire to eat; a feeling of satisfaction

• Hypothalamus - portion of brain that regulates satiety - influenced by

– blood glucose, bulk of meal, composition of meal, hormones

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What is Nutrition ?

• Nutrition defined as:– Science of foods – and their components (nutrients and other

substances),– including the relationships to health and disease

(actions, interactions and balances);– processes within the body (ingestion, digestion,

absorption, transport, functions and disposal of end products); and the social, economic, cultural and psychological implications of eating.

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Nutrients and Nourishment

• Nutrients - any substance in food that the body can use to obtain energy, build tissues, or regulate functions

• Essential nutrients - substances that must be obtained in the diet because the body either cannot make them or cannot make adequate amounts of them

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Six Classes of Nutrients

• Organic– Carbohydrates– Proteins– Lipids– Vitamins

• Inorganic– Minerals– Water

• Diet must supply about 45 Essential Nutrients

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General Functions of Nutrients• Fig 1.9• Regulate Body Process

• proteins, lipids, vitamins, minerals, water

• Contribute to cell and body structure• Growth and development of bone, muscle and other cells• proteins, lipids, vitamins, minerals, water

• Provide Energy• carbohydrates, proteins, lipids• calorie - heat energy needed to raise one gram of water

by one degree Celsius. (1 kcal = 1000 cal).• Food labels use cal in place of kcal

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Carbohydrates• Major source of fuel (4 kcal/gram)

• Carbon, Hydrogen and Oxygen

• Simple sugars - glucose– Sucrose (glucose-fructose)

• Complex sugars– storage forms - links between simple sugars – Eg, glucose-glucose-glucose-glucose-glucose-glucose-glucose

– Starch (potatoes, rice)

• Dietary Fiber (un-digestible - bran, apple skin)

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Lipids

• Concentrated fuel (9 kcal / g)• Fats (solid) and Oils (liquid) at

room temperature• Do not dissolve in water• Triglycerides are major form of lipid• Fatty acids are the basic structural unit

– Saturated - generally solid, animal derived– Unsaturated - generally liquid, plant derived

• Some Fatty acids are essential nutrients - vital for cell synthesis and repair – one table spoon of vegetable oil supplies our daily

requirements– omega 3 and omega 6 - healthy fish oils

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Proteins• Major component of Body Structure

• muscle, bone, enzymes, hormones

• Energy (4 kcal / g)

• Amino Acid is structural unit• 20 types, 9 are essential

• Typical consumption is 1.5 to 2 times dietary need– excess is used for energy or stored as carbohydrate or

FAT

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Vitamins and Minerals

• Needed in small amounts

• not a direct source of energy

• high potential for toxicity

• balanced diet can easily supply all vitamins and minerals

• should not rely on supplements

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Vitamins

• Essential - carbon containing substances (Organic)

• Enable many chemical reactions to occur in body

• 13 kinds• 4 fat soluble A, D, E and K

• potential for toxic build up

• 9 water soluble• easily excreted, but can be destroyed by cooking

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Minerals• Inorganic ions• Not a source of energy

• Role in facilitating metabolism• Iron in oxygen transport• Sodium in nerve conduction• Calcium in muscle contraction

• Make up structure of body and components of blood stream– eg. Calcium in bones

• Two groups - Major minerals and Trace minerals - categorization based on dietary needs

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Water

• Nourishes the body in many vital ways

• dissolves substances (solvent)• lubricates joints• provides a means of transport for nutrients and waste• Medium for temperature regulation and chemical processes

• body is ~ 60% water, need almost 2 L per day• not a source of energy

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Are you what you eat?

• The amount of nutrients your body needs varies widely from one nutrient to another.

• .5 Kg of energy food• 2.5 Kg of water• mg of vitamins and minerals

• Your structure is determined by genetic blueprint, you are not what you eat, but your food is the raw materials.

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Energy for Body Function• Energy - capacity to do work

– Chemical energy from food converted to mechanical, electrical and heat energy

• Carbohydrates, Fats, and Protein• Alcohol is also an energy source

– Not an essential nutrient– Typically a contributor to excess energy intake in the diet

• energy is in Carbon-Hydrogen bonds • Harnessed by Plants from Suns energy• Used to: - Build compounds

– Perform muscular movements– promote nerve transmission– maintain ion balance in cells

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• Energy in foods– Measured in kilocalories (kcal)

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Energy Intake• calorie - energy it takes to raise temperature of 1

gram of water 1 degree Celsius– Nutrition - use kilocalories (1000 calories) - same as

common Calorie

• Typical diet (% of total calories)– Protein 16%, Carbohydrates 50% Fats 33%

• Recommend – P(15%), C(50-60%), F(25-35%)

• Use Food labels - fig 2.11- Canadian p D12• Common Dietary Problems

– reduced activity, increased caloric intake• obesity, health risks

– low vegetable and fruit intake• Missing major sources of vitamins and minerals

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Calculating Energy in Foods• One bagel plus 1.5

ounces of cream cheese contains

• 39 grams of carbohydrate

• 10 grams of protein

• 16 grams of fat

• 39 g carbohydrate x 4 kcal/g = 156 kcal

• 10 g protein x 4 kcal/g = 40 kcal

• 16 g fat x 9 kcal/g = 144 kcal

• Total = 340 kcal

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Applying the Scientific Process to Nutrition

• Scientific method

• Types of studies– Epidemiological– Animal– Cell culture– Human

• Case control• Clinical trial

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Finding Scientific Information Versus Misinformation

• As scientific information is made accessible to more and more people, less detail is provided and more opinion and sensationalism are introduced.

• Sources include professional journals, scientific magazines, generalist magazines and newspapers, nightly news bites, unattributed Internet sites.

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Evaluating Information on the Internet: Red Flags of Junk Science

• Recommendations that offer a quick fix• Dire warnings of danger from a single product

or regimen• Claims that sound too good to be true• Simplistic conclusions drawn from a single

study• Dramatic statements that are refuted by

reputable scientific organizations• Evidence vs hype

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Kin 110Chapter 2

Nutritional Guidelines and Assessment

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Overview of Lecture • Chapter 2

• Tools for diet design• Food Guide and its uses• Dietary Guidelines• Recommended Nutrient Intakes• Food Labeling• Nutrient Density and the Exchange System• Nutritional Assessment

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Dietary Planning PrinciplesSix dietary planning principles form the foundation of all health diets.

Adequacy• provides sufficient energy and enough of all of

the nutrients to meet the needs of healthy people

Balance• provides an appropriate distribution of nutrients

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Dietary Planning Principles - kiloCalorie Control

• management of food energy intake (avoids over consumption of energy)• Nutrient Density - nutrients obtained in relation to overall kilocalories - aim

to maximize• Energy Density - energy obtained per gram of food - aim to minimize

Example of nutrient density1 cup skim milk 301 mg Calcium 85 kcal1 cup whole milk 290 mg Calcium 150 kcal

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Dietary Planning Principles cont.

Moderation• avoiding extremes of energy or nutrient

consumption• Keeping serving sizes reasonable

Variety• consuming a wide selection of different foods• why is variety important?

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Canada’s Guidelines for Healthy Eating

• Enjoy a VARIETY of foods• Emphasize cereals, breads, other grain

products, vegetables, and fruits• Choose lower fat dairy products, leaner

meats, and foods prepared with little or no fat• Achieve and maintain a healthy body weight

by enjoying regular exercise and healthy eating

• Limit salt, alcohol, and caffeine

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Eating Well with Canada’s Food Guide

• group foods according to the primary nutrients they contain & similarity in origin

• used to assess the diet for adequacy & assist in diet planning

• many foods can contribute to more than one food group

• a balanced diet means choosing foods from each group

• a varied diet means choosing different foods form within each food group

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Eating Well with Canada’s Food Guide

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How much from each food group should I consume?

Female (Age 19-50) Male (Age 19-50)

Create your own food guide

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What is a “serving” size?

Estimating Serving Sizes• 3 oz meat ≈ a deck of cards

• 1.5 oz of cheese ≈ 3 dominoes

• 1 cup ≈ a baseball

• 1 tsp ≈ tip of thumb

• 1 medium fruit ≈ 1 tennis ball

• 2 tablespoons ≈ golf ball or shot glass

• 2 once bagel ~ 1 hockey puck

• 1/2 cup cooked rice or pasta~ tennis ball

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Eating Well with Canada’s Food Guide

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Eating Well with Canada’s Food Guide

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Eating Well with Canada’s Food Guide

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Eating Well with Canada’s Food Guide

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Recommendations for Nutrient Intake

• Dietary Reference Intakes (DRIs)– Recommendations for nutrient intake– Developed by the Food and Nutrition

Board– Apply to healthy people in the United

States and Canada– Four basic elements

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Dietary Reference Intakes (DRIs)

• Estimated Average Requirement (EAR)– Amount that meets the nutrient

requirements of 50% of people in a life stage/gender group

– Based on functional indicator of optimal health

• Recommended Dietary Allowance (RDA)– Amount that meets the needs of most

people (97-98%) in a life stage/gender group

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Dietary Reference Intakes (DRIs)

• Adequate Intake (AI)– Amount thought to be adequate for most

people– AI used when EAR and RDA can’t be

determined

• Tolerable Upper Intake Level (UL)– Intake above the UL can be harmful

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Dietary Reference Intakes (DRIs)

• Using the DRIs– Population groups

• Assess adequacy of intake• Plan diets• Set policy and guidelines

– Individuals• Use RDA and AI as target levels for intake• Avoid intake above the UL

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Food Labels• Mandatory information on food labels

– Statement of identity– Net contents of the package– Name and address of manufacturer,

packer, distributor– List of ingredients

• Listed in descending order by weight

– Nutrition information

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Canadian Nutrition Food Labeling(p D12)

Nutrition Facts BoxNutrient information based on a specified amount of food for easy comparisons

Daily values based on recommendations for healthy eating. Provide context for the amount of nutrient.

allow for quick evaluation of contribution to daily needs, comparison between products and estimation of nutrient density

allows calculation of the percent energy derived from each of the energy yielding nutrients

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Food Labels: Claims

• Nutrient content claims– Descriptive terms, e.g., low fat, high fiber

• Health claims– Link one or more dietary components to reduced risk of

disease– Must be supported by scientific evidence

• Structure/function claims– Describe potential effects on body structure or function

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Nutritional Health States•Desirable Nutrition

•Intake supports body functions

•Undernutrition•Nutrient intake does not meet needs•body stores can make up for short term, but become depleted•body does not function appropriately •serious problems can arise with long term under nutrition•Symptoms develop, may take years for clinical evidence ( Skin, hair, nails, tongue, eyes

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Nutritional Health States•Overnutrition

•Prolonged over consumption of more than the body needs•long term can lead to toxic build up and serious disease Eg Iron •most common is excess energy intake•Eg. excess weight leads to serious disease

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Measuring Nutritional State•Overall body health is determined by the sum of its nutritional status for each nutrient•Components Include•Anthropometry - height, weight, skin folds, girths•Biochemical measurement - blood, urine analysis•Clinical Examination - signs of malnutrition

•Hair nails, skin, eyes, lips, mouth, bones…

•Dietary History - food intake over time•Economic Status - only a minor influence in North America (often worse diet with higher income), beginning to have larger impact worldwide

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Limits of Nutritional Assessment

•Can be a very long time between the onset of poor nutritional health and the first clinical evidence

•Often too late

•Calcium deficiency - low bone density, osteoporosis later in life (30 to 50 years).

•High Cholesterol - builds up in circulatory system, heart disease later in life.