NUTRITION

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NUTRITION
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INTRODUCTION

• For most people in the United States good
  nutrition is a matter of informed choice

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• 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

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• 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

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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

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Dietary Guidelines

• Aim for Fitness
• Aim for a healthy weight
• Be physically active each day
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Dietary Guidelines

• Build a Healthy Base
• Let the Pyramid guide your food
• choices Choose a variety of grains
• daily, especially whole grains
• Choose a variety of fruits and vegetables daily
• Keep food safe to eat
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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

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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 sugars Choose and prepare foods with
  less salt If you drink alcoholic beverages, do so
  in moderation

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• American Heart Associations 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

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• 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

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• American Cancer Societys 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

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• 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 Generals Report on
  Nutrition and Health offered comprehensive
  documentation for recommended dietary changes

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• 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

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• 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

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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
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• 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

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• 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

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• 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

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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

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• 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

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• Different foods provide different amounts of
  energy
• Carbohydrates 4 calories per gram
• Protein 4 calories per gram
• Fat/Lipid 9 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

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THE COMPOSITION OF FOOD

• Foods contain six types of chemical substances
• Proteins
• Carbohydrates
• Lipids (fats)
• Vitamins
• Minerals
• Water

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• 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

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• 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

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• 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

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• 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

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• Humans must obtain the eight essential amino
  acids from food
• Daily supply required amino acids are not
  stored
• High-quality dietary protein matches the bodys
  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

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• 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

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• 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

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THE COMPOSITION OF FOODCarbohydrates

• Nearly all the bodys cells use energy stored in
  carbohydrate molecules and are the principal
  source of the bodys energy
• Carbohydrates are also used to manufacture DNA
  (deoxyribonucleic acid)

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• 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)

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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

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THE COMPOSITION OF FOODCarbohydrates 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)

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THE COMPOSITION OF FOODSimple 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

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THE COMPOSITION OF FOODSimple 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

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THE COMPOSITION OF FOODSimple 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

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• 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)

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THE COMPOSITION OF FOODCarbohydrates 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

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• The are two main classes of complex
  carbohydrates starch (which is digestible)and
  fiber (which is not digestible)

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THE COMPOSITION OF FOODComplex 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

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• 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

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THE COMPOSITION OF FOODComplex 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

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• 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

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• 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

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THE COMPOSITION OF FOODLipids (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)

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• Lecithin which is essential to cell membranes
• Steroid hormones
• Vitamins A, D, E, K
• Bile acids

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• 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)

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• 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

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• 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

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• 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

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Two specific types of blood cholesterol

• 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

• 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

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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

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• 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

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THE COMPOSITION OF FOODMinerals

• 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

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• 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

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• 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

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THE COMPOSITION OF FOODPhytochemicals

• Plant matter contains hundreds of chemical
  substances, called phytochemicals, that
  positively affect human physiology
• Phytochemicals help destroy and eliminate toxins
  acquired from the environment

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• 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

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THE COMPOSITION OF FOODWater

• The human body is 60 to 70 percent water
• Water, an essential nutrient, is a major
  component of cells and blood

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• The popular maxim of drinking 8 glasses of water
  a day is probably a good rule of thumb

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• 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

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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

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FOOD ADDITIVESPreservatives

• Some additives are necessary to prevent spoilage
• About 20 of the worlds 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

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• 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 foods
  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

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• 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

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• 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

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FOOD ADDITIVESArtificial 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

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• 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

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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
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• Fast-food companies have responded to consumers
  concerns about nutrition by providing salads,
  baked potatoes, roast beef, and broiled chicken
  breasts

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VEGETARIAN DIETS

• Vegetarian diets can meet nutritional needs if
  planned properly
• The practice of vegetarianism appears to be
  growing in the United States

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• 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

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• 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

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• 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.