Why study Nutrition? To ensure proper nutrition for yourself –For normal lifestyle –For special situations Pregnancy Athletic performance Relationship

Why study Nutrition?• To ensure proper nutrition for yourself

– For normal lifestyle– For special situations

• Pregnancy• Athletic performance

• Relationship with morbidity, mortality– Cancer– Cardio-Vascular Disease– Diabetes Mellitus– Stoke

• Important in prevention, treatment, recovery• Prevents misinformation

Nutrition in Your Life• Diet

– The foods one consumes•The quality of which affects the risk of chronic diseases

Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning

Food choices• Personal Preference

– Tastes• Habit

– Cereal for breakfast• Ethnic Heritage or Tradition

– Most non-European cultures eat savory things for breakfast• Social interactions

– Parties• Availability, convenience and Economy

– Healthier foods tend to be more expensive– Study found that poorer neighborhoods had more fast food/less

healthy food options• Positive and Negative Associations

– Foods associated with being sick as a child

Food choices (contd)• Emotional Comfort

– Comfort foods (associations with home, growing up – even if you didn’t like it then or think it is unhealthy now)

• Values• Religion• Muslims – Halaal• Jews – Kosher• Hindus – Vegetarian• Other

• Environmentalists – Vegetarian/Vegans• Animal Rights activists - Vegetarian/Vegans• Concerned consumes - local produce, organic, migrant workers rights, GMOs

• Body Weight and Image• Nutraceuticals• Green Tea• Ephedra

• Nutrition and Health Benefits

Nutrition in Your Life• Food

– Derived from plant or animal sources•Provide energy and nutrients

–Used by the body for maintenance, growth, and repair


What does food provide?

• Energy– Energy -- The capacity to do work. The energy in

food is chemical energy, which the body converts to mechanical, electrical or heat energy

• Nutrients– Provide Energy– Provide raw materials to build body parts

• E.g. proteins mainly provide amino acids to build muscles,skin and make enzymes, hormones etc.

• Are less important as sources of energy

– Provide materials to keep body functioning

Energy Defined

• Energy is measured in kilocalories • A kilocalorie is a unit of heat (the amount

of heat necessary to raise the temperature of 1 liter of water 1o C)

• Energy yields of common nutrients– Carbohydrates (CHO): 4 kcal/gram – Protein: 4 kcal/gram – Fat: 9 kcal/gram – Alcohol also provides energy (7 kcal/gram),

but is a toxin, not a nutrient.

Energy Density• Low Energy Density is better for nutrition• More filling so

Nutrients in foods Nutrition in a raw potato

NutrientServing Size (150

grams/5.3 oz.)Potato

Calories 100

Protein 3 grams

Fat 0 grams

Carbohydrates

22 grams

NutrientServing Size (150

grams/5.3 oz.)Percent of U.S. RDA

(Est. 1973)

Vitamin A Trace -

Vitamin C21.43

35%

Thiamin .061 mg 4%

Riboflaving (B2)

.049 mg 2%

Niacin 1.76 mg 10%

Calcium 14 mg -

Iron 2.7 mg 10%

Vitamin B6 .352 mg 20%

Folic Acid 29.8 mcg 8%

Phosphorus 78.341 mg 8%

Magnesium 29.7 mg 8%

Zinc .524 mg 4%

Copper .245 mg 10%

Iodine .035 mg 15%

Source: Potato Market Basket Study 1978-79.

http://images.google.com/imgres?imgurl=http://www.leskincaid.com/food/images/russet%2520potato.jpg&imgrefurl=http://www.lallatin.com/specials/default.asp&h=195&w=280&sz=9&tbnid=MolZeSIhNG0J:&tbnh=75&tbnw=107&start=6&prev=/images%3Fq%3Dpotato%26hl%3Den%26lr%3D%26sa%3DN

Nutrients in the body

Remember – we were meant to be food for bears and other animals

Nutrients Defined

• Nutrients (Chemical composition)– Organic: CHO, Protein, Fat, Vitamins– Inorganic: Minerals, Water

• Nutrients (Energy)– Energy-yielding: CHO, Protein, Fat– Non-Energy-yielding: Minerals, Water, Vitamins

• Nutrients (Amounts needed)– Macronutrients Large amounts (many grams daily ) CHO,

Protein, Fat– Micronutrients Small amounts (typically milligrams daily)

Minerals, Vitamins• Nutrients (Source)

– Essential– Synthesized by the body

Non-nutrient components of food

• Fiber

• Phytochemicals

• Alcohols

Nutrients essential for humans

• Here are the known categories of essential nutrients for man. – water – calories (energy) from protein, carbohydrate or fat. – 8-10 essential amino acids (all 20 are necessary for protein

synthesis, but we can make some from other amino acids or from carbohydrate and ammonium ions).

– essential fatty acids – 13 vitamins (organic compounds required in small amounts).

These typically function as enzyme cofactors, e.g., niacin (precursor of NAD and NADP), riboflavin (precursor of FAD, FMN), pyridoxine or B6 (precursor of pyridoxal phosphate).

– 16-20 minerals (inorganic compounds required in "small" amounts).

What makes a nutrient essential?

• Omission from the diet leads to a decline in certain aspects of health.

• Restoration of the omitted nutrient to the diet before permanent damage occurs, will restore normal function to the aspects of health impaired by its absence.

• Have specific biological functions in the body. • Are needed to maintain life, but are not produced in the

body, or produced in amounts too small to maintain metabolism

• Biopterin is necessary in metabolism, but we can make all we need.

• In contrast, folic acid is equally necessary, but we cannot make it. Hence, folic acid is an essential nutrient

The Science of Nutrition –The Metric System

• Metric System – Also called System Internationale (SI)– With the primary exception of the US, the nations of the world use the SI system

• Measurements might be made in these basic units: – Length - meter – Volume - liter – Weight - gram – Temp - degrees Celsius – Energy – kilojoules

• The following set of modifying prefixes work for all basic units mentioned above: – 1kilo = 1000 (grams, or meters or liters)– 1 centi = 1/100 (grams, or meters or liters)– 1 milli = 1/1000 (grams, or meters or liters)– 1 micro = 1/1000,000 (grams, or meters or liters)

– Therefore • 1L = 1000mL (millileters)• 1g = 1000mg (milligrams)


Metric vs household measures

• Volume– 1Quart = 0.95 L (almost 1L)– 1 cup = 240 ml (little less 1/4th of a liter)– 1 ml = 0.03 fluid ounces

• Weight– 1 kg (kilogram) = 2.2 lb (pounds)– 1lb = 454 g (approximately ½ kg– 1g = 0.04 ounces– 1 oz = 28.35 g (approximately 30g)

• Length– 1 feet = 30.48 cm (centimeters )– 1 inch = 2.54 cmhttp://www.easysurf.cc/cnvert.htm#ci2

Metric vs household measures

• Temp– From F to C:

- subtract 32 - multiply by 5 - divide by 9

– From C to F: - multiple by 9 - divide by 5 - add 32

• Energy– 1 kcalorie = 4.2 kj (kjoules)

For help with various conversions use the last few pages of the textbook

The Science of Nutrition

• Human genome– The entire DNA sequence of a human being– DNA from two individuals of the same sex are

about 99.9% similar but the 0.1% difference decides how we respond to nutrition, medicines etc.

• Nutritional genomics– Personalized nutrition– Find out what individuals need – Way of the future


Nutrition Research


Nutrition Research


Nutrition Research


Nutrition Research• The Scientific Method

– Placebo effect•Blind experiment•Double-blind experiment

– Correlations and causes•Positive correlation vs. negative correlation

•Replication


Dietary Reference Intakes

• Estimated Average Requirements (EAR)– Average amount required to maintain specific

function in half the population

• Recommended Dietary Allowances (RDA)• Adequate Intakes

– When EAR is not known– Based on what healthy people consume

• Tolerable Upper Limits– Beyond this level the nutrient could become toxic


Energy Recommendations

• Estimated Energy Requirement– Average dietary intake (kcalories/day) of a

person of given age, gender, weight, height and physical activity level

• Acceptable Macronutrient Distribution Ranges: – Energy comes from

• Carbohydrate: 45% - 65%• Fat: 20% - 35%• Protein: 10% - 35%


DRI


For most nutrients RDA is set higher than average to ensure people like C get enough

EEREAR

DRI


Using Nutrient Recommendations

• Estimates of energy & nutrient intakes apply to healthy people

• Recommendations are NOT minimum requirements

• Recommendations are NOT optimal for all people


Using Nutrient Recommendations

• Recommendations should be met by consuming a varied diet

• Recommendations apply to average daily intakes

• Each DRI category serves a unique purpose


Nutrition Assessment of Individuals

• Malnutrition– Undernutrition vs. overnutrition

• Historical information– Health status, socioeconomic status, drug use

and diet• Anthropometric data

– Height, weight etc.• Physical examination

– Hair, skin, eyes, nails etc.• Laboratory tests

– Blood tests, urine tests


Nutrition Assessment of Individuals

Iron as an example

• Primary deficiency – Diet lacks iron

• Secondary deficiency– Body doesn’t absorb enough, excretes too much or uses iron

inefficiently• Subclinical deficiency

– Body is starting to use its iron stores– Covert symptoms

• No outward signs• Detected by tests

• Overt symptoms– Iron stores are exhausted – Not enough red blood cells– Weakness, fatigue, pale skin, headaches– Seen by physical examination


Diet and Health

• RDAs were set up to guard against not enough nutrients

• This still exists in some populations

• But now in most countries the problem is too much nutrition especially calories

• Or the problem maybe lifestyle choices

Diet and Health


Risk Factors for Chronic Diseases

• Risk factors persists– If you have high blood pressure at a young age, it is not likely

to go away with age.• Risk factors cluster

– Combination of obesity, high blood pressure, high cholesterol and high blood sugar

• Risk factors in perspective– Main risk factors that you can control

• Smoking• Obesity• No physical activity• Excessive alcohol consumption

– Main risk factors that are beyond your control• Genetics• Age• Gender


Assignment I

• Check out the assignments link on the website for more information.

Documents

Why study Nutrition? To ensure proper nutrition for yourself –For normal lifestyle –For special situations Pregnancy Athletic performance Relationship