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NUTRITION INTRODUCTION For most people in the United States good nutrition is a matter of informed choice Poor nutritional habits can contribute to ill health Too much cholesterol Too much saturated fat Too much refined sugar Too much salt Too few complex carbohydrates

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  • For most people in the United States good nutrition is a matter of informed choice
Poor nutritional habits can contribute to ill health
    • Too much cholesterol
    • Too much saturated fat
    • Too much refined sugar
    • Too much salt
    • Too few complex carbohydrates
    • Taking in more calories than expended
Good nutrition can be achieved by wise diet planning
    • Food fads are unnecessary
    • Diets should contain enough essential nutrients
    • Proper calories should be consumed
    • A variety of foods is recommended
dietary guidelines for eating right
  • To encourage and promote healthy dietary choices, the U.S. government, the World Health Organization, and the American Heart Association and American Cancer Society promote guidelines for good nutrition
dietary guidelines
Dietary Guidelines
  • Aim for Fitness
    • Aim for a healthy weight
    • Be physically active each day
dietary guidelines8
Dietary Guidelines
  • Build a Healthy Base
    • Let the Pyramid guide your food
    • choicesChoose a variety of grains
    • daily, especially whole grains
    • Choose a variety of fruits and vegetables daily
    • Keep food safe to eat
the food guide pyramid
The Food Guide Pyramid
  • To help implement the dietary guidelines, the U.S. government created the “Food Guide Pyramid” which promotes diets emphasizing grains, fruits, and vegetables, with moderate to little consumption of meat and diary products, and very little sweets and fats
dietary guidelines10
Dietary Guidelines
  • Choose Sensibly
    • Choose a diet that is low in saturated fat and cholesterol and moderate in total fat
    • Choose beverages and foods to moderate your intake of sugarsChoose and prepare foods with less saltIf you drink alcoholic beverages, do so in moderation
American Heart Association’s Dietary Guidelines (with your heart in mind)
    • Total fat intake should be less than 30 percent of total calories
    • Saturated fatty acid intake should be less than 10 percent of total calories
    • Polyunsaturated fatty acid intake should be no more than 10 percent of calories
Monounsaturated fatty acids make up the rest of the total fat intake, about 10 to 15 percent of total calories
  • Cholesterol intake should be no more than 300 milligrams per day
  • Sodium intake should be no more than 300 milligrams (3 grams) per day
American Cancer Society’s Dietary Guidelines (for reducing cancer risk)
    • Maintain desirable body weight
    • Eat a varied diet
    • Include a variety of both vegetables and fruits in the daily diet
    • Eat more high-fiber foods, e.g., whole grain cereals, legumes, vegetables, fruits
    • Cut down on total fat intake
    • Limit consumption of alcoholic beverages, if you drink at all
    • Limit consumption of salt-cured, smoked, and nitrate-preserved foods
Even though both guidelines appear to be different, the ultimate goal of a good nutritious diet can be achieved by following either one
  • In 1988 the first Surgeon General’s Report on Nutrition and Health offered comprehensive documentation for recommended dietary changes
There are those who criticize the Food Guide Pyramid because they say it accommodates politically powerful meat and dairy industries
  • Proponents of the Guide say that it provides a pictorial display placing the most healthy foods at the broad base and the least healthy at the top; they believe this allows for people to stop counting calories and build diets based on foods at the bottom of the Pyramid
A pattern for daily healthy food choices include
    • Choosing daily from breads, cereals, and other grain products, fruits, vegetables, meat, poultry, fish, and milk, cheese, and yogurt
    • Including different foods from within the groups
    • Having the smaller number of servings suggested from each group
    • Limiting total amount of food eaten to that needed to maintain desirable body weight
    • Choosing foods that are low in fat and sugars
    • Managing your intake of fats, sweets, and alcoholic beverages
reading the new food label
  • In 1990, the Nutritional Labeling and Education Act (NELA) became law
  • The Food and Drug Administration oversees this law which includes educating the consumer

FDA Labeling

Four primary messages officials hope you will gain when you read the new food label
    • You can believe the claims on the package
    • You can more easily compare products because serving sizes will be more comparable for similar products
    • By using the percent daily value, you can quickly determine whether a product is high or low in a nutrient
    • By consulting the daily values, you can determine how much, or how little, of the major nutrients you should eat daily
RDA lists values for protein, eleven vitamins, seven minerals
    • Assumes if these nutrients are present in the recommended amounts, then all others will be, too
    • Assumes the diet contains animal protein to provide essential amino acids
    • Assumes individuals are healthy and not stressed
    • Makes separate recommendations for pregnant and lactating women, and children
Recommended [Daily] Dietary Allowances (RDAs) outline the nutrient requirements of most Americans
    • Set by the Food and Nutrition Board of the National Academy of Sciences
    • Updated periodically to take into account recent research
energy for life
Energy for Life
  • Food is the source of energy for life
    • Ultimate source of food energy is sunlight
    • Plants convert solar energy into plant material
    • Humans get energy by eating plants or animals that have eaten plants
Energy is measured in calories
    • One calorie is the energy required to raise one gram of water from 14.5 degrees to 15.5 degrees Celsius
    • Nutritional calorie is a unit of energy often referred to as a kilocalorie
    • A kilocalorie is equivalent to 1,000 calories
Different foods provide different amounts of energy

Carbohydrates4 calories per gram

Protein4 calories per gram

Fat/Lipid9 calories per gram

Amount of energy needed for physical activity depends on strenuousness of activity, body weight, and environmental temperature

Energy needs are being met if a person is neither overweight nor underweight

the composition of food
  • Foods contain six types of chemical substances
    • Proteins
    • Carbohydrates
    • Lipids (fats)
    • Vitamins
    • Minerals
    • Water
Digestion is the breakdown of food and the absorption of nutrients by the gastrointestinal system
    • The mouth is the initial site of digestion
    • Chewed and softened food is passed from the mouth to stomach via the esophagus for additional breakdown
    • Nutrients are absorbed from the intestines into the blood
    • The liver regulates the release of nutrients
    • Nondigested material is excreted in feces
Proteins are involved in virtually all essential functions of the body
    • Primary components of the skeleton
    • Make up hair and nails
    • Thousands of chemical reactions mediated by enzymes
    • Antibodies protect body from foreign substances and microorganisms
    • Hemoglobin transports oxygen via circulatory system
    • Proteins act as receptors on surfaces of cells
Proteins are made up of amino acids linked together in chains
    • Twenty different amino acids
    • Each type of protein has a unique amino acid composition and sequence
    • Optimum protein synthesis requires all amino acids in sufficient amounts
Amino acids are classified as essential and nonessential
    • Eight essential amino acids are required by adults and nine are requiredby infants
    • Animal sources of protein include: milk, milk products, meat, fish, poultry and eggs
    • Plant sources of protein include: breads and cereals, legumes, nuts and seeds
Humans must obtain the eight essential amino acids from food
    • Daily supply required; amino acids are not stored
    • High-quality dietary protein matches the body’s needs for essential amino acids
    • Most vegetable protein has insufficient essential amino acids; must mix protein from different sources to make complete protein
    • Generally supplied by daily intake of 45-60 grams of dietary protein
High meat consumption may contribute to disease
    • Most people in the U.S. and Canada consume twice the protein they actually utilize
    • Many kinds of meat are high in fat
Countries with high meat consumption (New Zealand, U.S. and Canada) have high incidences of colon cancer
    • May be due to pollutants in the meat (cancer-causing/cancer-promoting pesticide residues (DDT), industrial chemicals (PCBs), hormone growth promoters (DES), dyes for color enhancement, and preservatives such as nitrates and nitrites)
    • May also be due to the way meat is digested
the composition of food carbohydrates
  • Nearly all the body’s cells use energy stored in carbohydrate molecules and are the principal source of the body’s energy
  • Carbohydrates are also used to manufacture DNA (deoxyribonucleic acid)
The body can manufacture carbohydrates from other nutrients
    • Because of this they are not considered essential nutrients
    • Carbohydrates are needed in diets to prevent breakdown of body protein (as in muscle tissue)
there are two kinds of carbohydrates
Simple sugars - a class of carbohydrates called monosaccharides; all carbohydrates must be reduced to simple sugars to be digested

Complex carbohydrates - a class of carbohydrates called polysaccharides; foods composed of starch and cellulose

There are two kinds of carbohydrates:
the composition of food carbohydrates simple sugars
THE COMPOSITION OF FOOD:Carbohydrates: Simple Sugars
  • Simple sugars are made of one or two molecules only
    • Glucose is the most common simple sugar and is found in all plants and animals
      • Glucose circulates in the bloodstream and is commonly referred to as “blood sugar”
      • Principal cellular energy source
      • Body converts all sugars to glucose
      • Used as sweet additive in manufactured foods (“corn sugar”)
the composition of food simple sugars fructose
THE COMPOSITION OF FOOD:Simple Sugars: Fructose
  • Fructose is one of the sweetest sugars found in fruits and honey
    • Chemically similar to glucose
    • Sweeter than glucose and other simple sugars which means you need less to taste sweet
the composition of food simple sugars sucrose
THE COMPOSITION OF FOOD:Simple Sugars: Sucrose
  • Sucrose is common table sugar (also the “refined” sugar added to many packaged foods)
    • Consists of one glucose and one fructose molecule
    • Glucose and fructose are split during digestion
the composition of food simple sugars lactose
THE COMPOSITION OF FOOD:Simple Sugars: Lactose
  • Lactose is found principally in diary products
    • Consists of one glucose molecule plus one galactose molecule
    • When lactose is digested, glucose and galactose are separated and the galactose is converted to glucose
Most babies can digest lactose, however, some older children and adults cannot because they lack the enzyme lactase, which splits lactose into glucose and galactose
  • Lack of this enzyme causes gastrointestinal upset, diarrhea, and sometimes cause a severe illness in those who are lactase-deficient (or sometimes referred to as lactose intolerant)
the composition of food carbohydrates complex carbohydrates
THE COMPOSITION OF FOOD:Carbohydrates: Complex Carbohydrates
  • Complex carbohydrates are many simple sugars linked together
  • Sources include: grains (wheat, rice, corn, oats, barley); legumes (peas, beans); the leaves, stems, and roots of plants; and some animal tissue
The are two main classes of complex carbohydrates: starch (which is digestible)and fiber (which is not digestible)
the composition of food complex carbohydrates starch
THE COMPOSITION OF FOOD:Complex Carbohydrates: Starch
  • Starch consists of many glucose molecules linked together
  • Animal and humans produce a starch in muscle and liver tissue called glycogen
  • Glycogen breaks down when the organism needs glucose to produce energy
Starch in the diet comes primarily from wheat
    • Wheat kernels crushed to liberate bran, endosperm, and germ
    • 70 percent extraction produces common white flour (mostly endosperm) primarily used in baking
    • 70 percent extraction flour has lost many nutrients, some of which are replaced by the manufacturer, but not all
    • 90 percent extraction is whole grain flour
    • Not all brown bread is “whole grain”
the composition of food complex carbohydrates fiber
THE COMPOSITION OF FOOD:Complex Carbohydrates: Fiber
  • There are two kinds of fiber, insoluble fiber and soluble fiber
  • Insoluble fiber cannot dissolve in water
  • Soluble fiber can be dissolved in water
  • Insoluble fiber is made up of cellulose and hemicellulose
It is recommended that individuals consume 20-35 grams of fiber daily, regardless of the type of fiber (the differences in insoluble and soluble fiber are not significant for nutritional and health purposes)
  • Fiber adds bulk to feces, preventing constipation and related disorders
Fiber decreases the time material spends in the GI tract, helping reduce risk of diverticular disease and cancer of the colon and rectum
  • High fiber diets may also help reduce the risk of heart disease and some cancers
the composition of food lipids fats
  • Lipids are a group of substances that are relatively insoluble in water
  • Some of these substances include:
    • Triglyceride (body fat)
    • Some of these substances include cholesterol (a fat-like compound occurring in bile, blood, brain and nerve tissue, liver and other parts of the body)
Lecithin which is essential to cell membranes
  • Steroid hormones
  • Vitamins A, D, E, K
  • Bile acids
Linoleic acid is the only essential dietary lipid; it is found in safflower, sunflower, and corn
  • A fat is classified as saturated, monounsaturated, or polyunsaturated
    • Saturated and unsaturated fats are made up of fatty acids (saturation refers to the number of hydrogen atoms in the fatty acids)
A saturated fat acid carries all the hydrogen atoms it can; saturated fats are found in whole milk, egg yolks, meat, meat fat, coconut and palm oils, chocolate, margarine, and hydrogenated vegetable oils
  • Unsaturated fats (which include both monounsaturated and polyunsaturated fats) are derived from plants
  • Monounsaturated fats are found in olive oil and some nuts
  • Polyunsaturated fats are found primarily in safflower, cottonseed, corn, soybean, and sesame seed oils; salad dressing made from oils; and fatty fish
Diets high in cholesterol and saturated fat are believed to increase the risk of coronary heart disease, some cancers and obesity
  • It is recommended that individuals consume no more than 300 mg cholesterol per day and limit saturated fat intake to 10 percent or less of total calories
  • Polyunsaturated fatty acid (PUFA) is a saturated fat except for two or more parts that are unsaturated; polyunsaturated fats tend to lower blood cholesterol
Amount ingested depends on foods eaten
    • Some foods (e.g. egg yolks) are high in cholesterol
    • Some foods (e.g. vegetable oils) are high in unsaturated fat
two specific types of blood cholesterol
Low-density lipoproteins (LDL) sometimes referred to as “bad” cholesterol, causes cholesterol to build up on the walls of your arteries increasing your risk of heart disease

High-density lipoproteins (HDL) sometimes referred to as “good” cholesterol, helps your body get rid of cholesterol in your blood; the higher your HDL the better as it helps reduce the risk of heart disease

Two specific types of blood cholesterol
the composition of food vitamins
  • Vitamins are biological molecules needed to facilitate many life-sustaining processes
  • The body cannot manufacture vitamins
  • Vitamins are classified as water-soluble or fat-soluble
    • There are nine water-soluble vitamins
    • There are four fat-soluble vitamins
Antioxidants are substances that can inhibit the oxidation of other compounds called free radicals (Vitamins A, C and E)
  • Antioxidants are associated with lower risk of cancer in upper GI, colon cancer, breast and lung cancer, and reduced risk of heart disease
    • Antioxidants are found in a variety of vegetables and fruits and can be obtained in supplements
the composition of food minerals
  • Nonorganic chemical elements are needed to facilitate many living functions
    • Sodium and potassium are needed for nerve conduction and muscle function
    • Magnesium, zinc, copper, and cobalt facilitate biochemical conversions
    • Iron is needed for oxygen transport by red blood cells
Iodine is needed to manufacture thyroid hormone
    • Calcium and phosphorus are needed for teeth and bones
  • Minerals are found in nearly all foods
    • Eating a variety of foods, especially fresh fruits and vegetables, gives sufficient quantities
    • Women and growing children must get enough iron
Too much sodium contributes to high blood pressure
    • Excess comes from salting food
    • Manufactured and restaurant foods have added salt
    • Body needs only 2 grams of salt each day; often as much as 20 grams is ingested
the composition of food phytochemicals
  • Plant matter contains hundreds of chemical substances, called phytochemicals, that positively affect human physiology
  • Phytochemicals help destroy and eliminate toxins acquired from the environment
Isoprenoids are contained in a number of fruits, vegetables, cereal grains, and citrus oils; associated with lowering cancer risk
  • Flavonoids have been associated with reducing the risk of heart disease; they are found in tea, onions, apples and wine
  • Phytoserols and tocotrienols are found in barley, wheat, corn and a variety of seeds; associated with lowering levels of cholesterol in the blood
the composition of food water
  • The human body is 60 to 70 percent water
  • Water, an essential nutrient, is a major component of cells and blood
Body water is maintained by sophisticated control mechanisms
    • Low body water leads to thirst
    • High body water causes hormone stimulation of kidneys, leading to additional urine production
    • Illness (fever), living in harsh environments, and exercise are reasons to be concerned with sufficient water intake
  • Caffeine and alcohol are diuretics
food additives
  • Most manufactured foods have additives for:
    • Texture
    • Stability
    • Flavor
    • Color
    • Longer shelf life
    • Sales appeal
  • Two common additives are preservatives and artificial sweeteners
food additives preservatives
FOOD ADDITIVES:Preservatives
  • Some additives are necessary to prevent spoilage
    • About 20% of the world’s food supply is lost to spoilage each year
    • Common preservatives are: BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene), and sodium nitrite
      • Each of these can be toxic if taken in excess; in specified amounts they are presumed safe in food
Sulfites in the form of sulfur dioxide, sodium sulfite, sodium/potassium bisulfate, and sodium/potassium metabisulfite are added to many foods to kill bacteria and slow the food’s breakdown (spoilage)
    • Sulfites are added to wine to stop fermentation
    • Sulfites were added to restaurant salad bars to keep freshness, but that practice has decreased significantly because people became ill
Food can be preserved nonchemically with gamma irradiation to kill fungi, bacteria, and other microorganisms
    • Approved by the FDA for use on fruits, vegetables, wheat, and pork
    • Opponents of gamma irradiation are concerned about the safety of irradiation
    • Irradiated foods carry a small flower-like symbol, or the word “picowaved” or “treated by irradiation”
Many food additives are nutritionally unnecessary and may adversely affect health
    • Tartrazine is a yellow dye added to hundreds of manufactured foods; the FDA estimates that as many as 100,000 Americans are intolerant to tartrazine
  • The words “natural” and “organic” do not necessarily mean that a food is free of additives
  • Food product labels list additives in descending order of relative amounts
food additives artificial sweeteners
FOOD ADDITIVES:Artificial Sweeteners
  • Artificial sweeteners are most widely used in diet soft drinks
    • The major artificial sweeteners are: *saccharin, and *aspartame (“Nutrasweet”); all three have been associated with health risks
The earliest sweeteners (cyclamates and saccharin) were found to cause cancer in experimental animals
    • Research data were not strong enough to cause outright banning of these substances
fast foods
  • Each day about 20 percent, or 46 million people, of the U.S. population eat at a fast-food restaurant
  • Convenience notwithstanding, fast-food items must be chosen carefully because many contain high quantities of saturated fat, cholesterol, and salt, with few carbohydrates, and little Vitamins A and C

Food Finder

Fast-food companies have responded to consumers’ concerns about nutrition by providing salads, baked potatoes, roast beef, and broiled chicken breasts
vegetarian diets
  • Vegetarian diets can meet nutritional needs if planned properly
    • The practice of vegetarianism appears to be growing in the United States
There are three kinds of vegetarian diets
    • Vegan or strict vegetarian - excludes all animal products including milk, cheese, eggs, and other dairy products
    • Lacto-vegetarians - exclude meat, poultry, fish and eggs, but include dairy products
    • Lacto-ovo-vegetarians -exclude meats, poultry, and seafood, but include eggs and dairy products
Research indicates that vegetarians are generally at lower risk than nonvegetarians for coronary heart disease, hypertension, some forms of cancer, non-insulin diabetes, and obesity
  • People are vegetarians for many reasons
    • Increased interest in health (reduce risk of certain diseases)
    • Ecology and world issues
    • Religion
    • Economics
    • To avoid killing animals
There are several reasons for being a vegetarian, including increased interest in health, increased interest in ecology and world issues, economical issues, and the philosophy of not killing animals. A strict vegetarian diet eliminates all animal products, including milk, cheese, eggs, and other dairy products.