Download Chapter 7

Chapter 7
Nutrition
Your Responsibility
• Did you read the assigned chapter before
coming to class?
• Did you make appropriate notes?
• Did you try the Assess Your Knowledge at the
beginning of the chapter and the Vocabulary
Challenge at the end?
Student Learning Outcomes
Student Self-Assessment
• Can you list the six major nutrients and state their
purposes?
• Do you know the major differences between the
USDA ChooseMyPlate, the Harvard Healthy
Eating Pyramid, and the Mediterranean Pyramid?
• Do you know what conditions, rules, or laws
organic foods must follow?
• Do you know the difference between food
allergies and food intolerances?
Elements of Nutrition
The Digestive Process
• Digestion begins in the mouth, where food is
broken down and then passed into the
gastrointestinal tract.
• The stomach releases gastric enzymes that turn
food into a liquid called chyme.
• About 20 percent of food is released into the
bloodstream from the stomach.
• The small intestine does the bulk of the digestive
work.
• Undigested chyme enters the large intestine,
where it is processed for excretion.
The Digestive System
Energy in Food
A calorie is a measure of the energy a food
contains.
• Fats provide 9 calories per gram.
• Carbohydrates provide 4 calories per gram.
• Proteins provide 4 calories per gram.
• Alcohol provides 7 calories per gram.
Carbohydrates
• The body’s preferred energy source.
• Are found in all grains, grain products,
legumes, nuts, all fruits and vegetables.
• Excess carbohydrates can be stored in the liver
and muscle as glycogen.
• Recommended intake of carbohydrate is from
45–65 percent of total calories.
• Carbohydrates are classified as either simple
or complex.
Simple Carbohydrates
• Simple carbohydrates are either
monosaccharides or disaccharides.
• They are quickly digested and can raise blood
sugar levels quickly.
• Simple carbohydrates are found in sodas, jams,
jellies, candy, and sugar.
• Fruits, fruit juices, and milk are primarily simple
carbohydrates, but unlike the others, these do
supply vitamins, minerals, and may contain
protein and fiber.
Complex Carbohydrates
• These are polysaccharides.
• They take longer to digest and do not raise
blood sugar levels quickly.
• Examples include cereals, rice, breads, pasta,
and some vegetables and fruits.
• Complex carbohydrates also contain vitamins,
minerals, and sometimes fiber and protein.
Complex Carbohydrates–Either Whole
Grain or Refined Grains
• Whole grain complex carbohydrates contain all parts of
the grain kernel, including the bran layer, the
endosperm, and the germ.
• As a result, they naturally contain fiber, B and E
vitamins, minerals, phytonutrients, and a small amount
of unsaturated fat.
• Refined grains are made when the bran, endosperm,
and germ are separated. The endosperm is used to
make flour, but its nutritional value is now reduced by
between 25 and 90 percent. The government
mandates that it must be “enriched” to a specific level
that is still lower than nutrients contained in the whole
grain.
The Glycemic Index
• Carbohydrates cause blood sugar to rise to
provide necessary energy.
• The effect a food has to raise blood glucose is
measured by the glycemic index.
• People with health concerns might find the
glycemic index helpful in controlling blood
sugar levels.
Fiber
• Fiber is a non-digestible form of carbohydrate.
• Dietary fiber occurs naturally in food, while
functional fiber is either synthesized or extracted
from a food source.
• Fiber is essential to health, and recommendations
are that adult males need about 38 grams of fiber
each day, and adult females about 25 grams of
fiber each day.
• Fiber is found in whole grains, vegetables, fruits,
legumes, nuts, and beans.
MENTAL BREAK
• Why are athletes given fruit juice and sugarcontaining beverages during breaks?
Proteins
• Proteins are made up amino acids. Some are
essential and must be consumed, while the body
can make other amino acids.
• A protein that contains all 8 essential amino acids
is known as a complete protein. Meat, chicken,
fish, milk, cheese are all complete proteins.
• A protein that does not contain all 8 essential
amino acids is known as an incomplete protein.
• Combining different incomplete proteins can
provide all the essential amino acids.
Recommended Intake of Proteins
• Adults need a minimum of 0.8 grams of
protein per kilogram of body weight.
• For a person weighing about 160 pounds, this
becomes about 64 grams of protein.
• Most Americans eat more than enough
protein, and excess cannot be stored.
• Excess protein may be harmful to health.
• Proteins are needed to build and repair cell
tissue and provide some energy.
High Protein Diets
• High-protein diets usually eliminate or reduce
carbohydrates.
• This may result in weight loss.
• Over the short term, high protein diets are probably
not harmful, but if maintained, may increase the risk
for coronary heart disease, and renal, bone, and liver
abnormalities.
• In a high-protein diet, the body may resort to fat for
energy. When the body breaks down fat, ketones are
released. In extreme situations, ketoacidosis might
occur, which can lead to coma and even death.
Fats (lipids)
• Fats are necessary for healthy skin, hair,
insulating organs, maintaining body temperature,
and are used in cellular functions.
• Moderate consumption is essential for health,
but over-consumption is harmful.
• When too many fat calories are consumed, the
excess is converted into triglycerides.
• Less than 30 percent of total calories should
come from fat.
• Fats are either saturated, polyunsaturated, or
monounsaturated.
Saturated Fats
• Saturated fats are found in tropical oils such as palm
and coconut oils, and in all animal source foods.
• The chemical structure of a saturated fat is fully
saturated with hydrogen atoms, and does not contain
double bonds between carbon atoms. This makes most
saturated fat hard at room temperature.
• This type of fat has been shown to increase the risk of
coronary diseases, cancers, diabetes, obesity, and
contribute to high cholesterol levels.
• Less than ten percent of total fat should be in the form
of saturated fat.
Unsaturated Fats (polyunsaturated and
monounsaturated)
• Unsaturated fats come from plant sources.
• They contain far less hydrogen than saturated fats.
• They differ from saturated fats in that their chemical
structure contains double bonds.
• Monounsaturated fats contain only on double-bonded
carbon atom, while polyunsaturated fats contain more
than one double bond.
• Corn, safflower, sesame, soybean, and sunflower oils
are high in polyunsaturated fat, while canola, olive,
avocado, and peanut oils are high in monounsaturated
oil.
Trans Fatty Acids (TFAs)
• TFAs are found in small quantities in beef,
pork, and the butterfat in milk and butter.
• They are also formed when liquid unsaturated
oil is partially hydrogenated to make
shortening, margarine, or cooking oil.
• Partially hydrogenated oils provide about 75
percent of the TFA in the US Diet.
• They increase risk for coronary artery disease
and high blood cholesterol.
Microelements of Nutrition
• Vitamins
• Minerals
• Antioxidants
• Phytonutrients
Do You Need a Multivitamin?
• In 2003, the Annals of Internal Medicine published a
study that demonstrated a lack of infection risk benefit
provided by taking multivitamins in the general
populations, but subjects with diabetes did experience
fewer infections.
• The strength of the evidence currently available does
not show that taking a multivitamin prevents cancer,
cardiovascular disease, hypertension, cataracts, or agerelated degeneration.
• Although there is little evidence to show that taking
multivitamins has a positive impact on health in the
general population, certain populations (those
undernourished or those with diabetes) may
experience a benefit.
Guidelines for Healthy Eating
• 2010 Dietary Guidelines for Americans
• Daily Reference Intakes
• Daily Recommended Values
Healthy Dietary Plans
•
•
•
•
The USDA ChooseMyPlate
The Harvard Healthy Eating Pyramid
The Mediterranean Pyramid
The Vegetarian Diet Pyramid
1.
2.
3.
4.
Balance calories.
Enjoy your food, but eat less.
Avoid oversized portions.
Eat more vegetables, fruits, whole grains, and fat-free
or 1% milk and dairy products.
5. Make half your plate fruits and vegetables.
6. Switch to fat-free and low-fat (1%) milk.
7. Make half your grains whole grains.
8. Cut back on foods high in solid fats, added sugars and salt.
9. Compare sodium in foods.
10. Drink water instead of sugary drinks.
* Abstracted from ChooseMyPlate, “10 Tips to a Great Plate” (http://www.choosemyplate.gov/healthy-eating-tips/ten-tips.html)
Consumer Issues in Nutrition
•
•
•
•
•
Organic Foods
Genetically Modified Foods
Irradiated Foods
Food Allergies
Food Intolerances
Choosing a Diet Based on Health Decisions
Responsibility and Accountability
Responsibility
• Taking responsibility for your nutrition
requires that you are informed and use this
information to make better food choices.
• Making the right choices and planning can
lead to a more nutritious and less harmful
diet.
Accountability
• You may be aware of your own
accountability for poor nutritional choices
now. Perhaps you are overweight, often
tired, or unable to exercise as you might
like.
• Making healthier choices more frequently
than unhealthy choices is a step in the right
direction.