Nutrition Basics

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					Nutrition Basics

 You are what
 you eat!!!

• Essential nutrients = substances the
  body must get from food because it
  cannot manufacture them at all or fast
  enough to meet its needs:
  – Proteins
  – Carbohydrates
  – Fats
  – Vitamins
  – Minerals
  – Water
             Energy from Food
• Kilocalorie = a measure of energy content in
  food; the amount of heat it takes to raise the
  temperature of 1 liter of water 1°C; commonly
  referred to as “calorie”
• Three classes of essential nutrients supply
  – Fat = 9 calories per gram
  – Protein = 4 calories per gram
  – Carbohydrates = 4 calories per gram

  *Although alcohol is NOT a nutrient it supplies
    seven calories per gram!
    Proteins—The Basis of Body
• Protein = a compound made of amino acids that
  contains carbon, hydrogen, oxygen, and
• Of twenty common amino acids in foods, nine
  are essential
• Proteins form key parts of the body’s main
  structural components—muscles and bones—
  and of blood, enzymes, cell membranes, and
  some hormones

    Complete and
 Incomplete Proteins
• Complete protein sources = foods that
  supply all the essential amino acids in
  adequate amounts
  – Meat, fish, poultry, eggs, milk, cheese, and soy
• Incomplete protein sources = foods that
  supply most but not all essential amino
  – Plants, including legumes, grains, and nuts

Recommended Protein Intake

          • Adequate daily intake
            of protein
            – 0.8 gram per kilogram
              (0.36 gram per pound)
              of body weight
          • Acceptable
            Distribution Range
            – 10–35% of total daily
              calories as protein

                Fats - Essential in
                 Small Amounts
• Fats
  – supply energy, insulate the body, support and
    cushion organs, absorb fat-soluble vitamins,
    add flavor and texture to foods
• Essential fats
  – linoleic acid and alpha-linolenic acid are key
    regulators of body process such as the
    maintenance of blood pressure and the
    progress of a healthy pregnancy

Types and Sources of Fats
• Saturated fat = a fat with no carbon-carbon
  double bonds; usually solid at room
  – Found primarily in animal foods and palm and
    coconut oils
  – Leading sources in our diets are: red meats,
    whole milk, cheese, hot dogs and lunch meats
• Monounsaturated fat = a fat with one
  carbon-carbon double bond; usually liquid at
  room temperature
  – Found in certain vegetables, nuts, and vegetable
    oils (olive, canola, safflower, & peanut oils
Types and Sources of Fats

    • Polyunsaturated fat
      – a fat with two or more carbon-
        carbon double bonds; usually
        liquid at room temperature
      – Found in certain vegetables,
        nuts, and vegetable oils
        (soybean, corn, & cottonseed
        oils) and in fatty fish

   Types and Sources of Fats
• Two key forms of polyunsaturated fats:
   – Omega-3 fatty acids = the endmost double
     bond of a polyunsaturated fat occurs three
     carbons from the end of the fatty acid chain
     • Found primarily in fish
  – Omega-6 fatty acids = the endmost double
    bond of a polyunsaturated fat occurs six
    carbons from the end of the fatty acid chain
     • Found primarily in certain vegetable oils,
       especially corn, soybean, and cottonseed oils

              Trans Fatty Acids
• The process of hydrogenation, in
  which hydrogens are added to
  unsaturated fats,
   – produces a mixture of saturated fatty
     acids and standard and trans forms of
     unsaturated fatty acids
• Trans fatty acids have an atypical
  shape that affects their chemical
• Leading sources in our diet are
   – french fries, fried chicken, cakes,
     cookies, pastries, doughnuts, chips, &
     stick margarine
           Fats and Health
• Fats affect blood cholesterol levels
  – Low-density lipoprotein (LDL) = “bad”
  – High-density lipoprotein (HDL) = “good”
• Saturated and trans fats raise levels of
  LDL; trans fats also lower levels of HDL
• Unsaturated fats lower levels of LDL

Fats and Health
• Fats also affect triglyceride
  levels, inflammation, heart
  rhythm, blood pressure, and
  cancer risk
• Best choices
  – monounsaturated fats and
   polyunsaturated omega-3 fats
• Limit intake of saturated and
  trans fats
  Saturated and Trans Fats:
Comparing Butter and Margarine


   spread                          Saturated fat
    Tub                            Trans fat
  margarine                        Other fats

              0   5     10    15
          Grams of fat in 1         SOURCE: Food an Drug Administration

            tablespoon                                                    15
                              Total, Saturated, and Trans Fat
                                Content of Selected Foods

                              30                                                                 Other fats
Total fat grams per serving

                                                                                                 Trans fat
                                                                                                 Saturated fat




                                   French fries   Doughnut   Pound cake Potato chips   Candy bar          Milk (whole)

                                                                                       SOURCE: Food an Drug Administration

   Recommended Fat Intake

• Adequate daily intake of fat:
                       Men         Women
Linoleic acid          17 grams    12 grams
Alpha-linolenic acid   1.6 grams   1.1 grams
   = about 3–4 teaspoons of vegetable oil
• Acceptable Macronutrient Distribution Range
  = 20–35% of total daily calories as fat

     Carbohydrates - An Ideal
        Source of Energy
• The primary function of dietary carbohydrate
  – to supply energy to body cells.
• Cells in the brain, nervous system, and blood,
  – use only carbohydrates for fuel
• During high-intensity exercise,
  – muscles get most of their energy from carbohydrates
• During digestion,
  – carbohydrates are broken into single sugar molecules
    such as glucose for absorption;
  – the liver and muscles take up glucose and store it in
    the form of glycogen
 Simple and Complex Carbohydrates
• Simple carbohydrates contain one or two sugar
  units in each molecule
  – Found naturally in fruits and milk and added to many
    other foods
  – Include sucrose, fructose, maltose, and lactose
• Complex carbohydrates consist of chains of
  many sugar molecules
  – Found in plants, especially grains, legumes, and tubers
  – Include starches and most types of dietary fiber

 Whole Grains
 Before they are processed, all
  grains are whole grains consisting
  of an inner layer of germ, a middle
  layer called the endosperm, and
  an outer layer of bran
 During processing, the germ and
  bran are often removed, leaving
  just the starchy endosperm
 Refined carbohydrates usually
  retain all the calories of a whole
  grain but lose many of the
Refined Carbohydrates Versus
        Whole Grains
• Whole grains are higher than refined
  carbohydrates in fiber, vitamins, minerals, and
  other beneficial compounds
• Whole grains take longer to digest
  – Make people feel full sooner
  – Cause a slower rise in glucose levels
• Choose foods that have a whole grain as the
  first item on the ingredient list on the label
  – Whole wheat, whole rye, whole oats, oatmeal,
    whole-grain corn, brown rice, popcorn, barley, etc.

            Glycemic Index
• Consumption of carbohydrates
  – causes insulin and glucose levels in the blood
    to rise and fall
• Glycemic index
  – is a measure of how the ingestion of a
    particular food affects blood glucose levels
• Foods with a high glycemic index
  – cause quick and dramatic changes in glucose
• Diets rich in high glycemic index foods
  – are linked to increased risk of diabetes and
    heart disease
Recommended Carbohydrate Intake
• Adequate daily intake of carbohydrate
  – 130 grams
• Acceptable Macronutrient Distribution Range
  – 45–65% of total daily calories as carbohydrate
• Limit on intake of added sugars
   – Food and Nutrition Board:
     • 25% or less of total daily calories
  – World Health Organization:
     • 10% or less of total daily calories
  – MyPyramid:
     • 32 grams (8 tsp) in a 2000-calorie diet
  Acceptable Macronutrient
Distribution Ranges: Summary

• Protein
  – 10–35% of total daily calories
• Fat
  – 20–35% of total daily calories
• Carbohydrate
  – 45–65% of total daily calories

        Fiber - A Closer Look
• Dietary fiber
  – nondigestible carbohydrates and lignin that are
    present naturally in plants
• Functional fiber
  – nondigestible carbohydrates isolated from
    natural sources or synthesized in a lab and
    added to a food or supplement
• Total fiber
  – dietary fiber + functional fiber
• Fiber does not provide calories                 25
                 Types of Fiber
• Soluble (viscous) fiber
   – fiber that dissolves in water or is broken down by
     bacteria in the large intestine (oat bran, legumes)
   – Slows the body’s absorption of glucose
   – Binds cholesterol-containing compounds
• Insoluble fiber
   – fiber that doesn’t dissolve in water (wheat bran, psyllium
   – Makes feces bulkier and softer
   – Helps prevent constipation, hemorrhoids, and
                  Sources of Fiber

• All plant foods contain fiber, but processing
  can remove it
• Good sources of fiber:
  – Fruits (especially whole, unpeeled fruits)
  – Vegetables
  – Legumes
  – Oats (especially oat bran)
  – Whole grains and wheat bran
  – Psyllium (found in some cereals and laxatives)
Recommended Intake of Fiber
• Women
  – 25 grams per day
• Men
  – 38 grams per day
• Americans currently
  – about half this amount
• Vitamins
  – organic (carbon-containing) substances needed
    in small amounts to help promote and regulate
    chemical reactions and processes in body cells.
• Four vitamins are fat-soluble
  – Vitamin A, D, E, and K
• Nine vitamins are water-soluble
  – C and the eight B-complex vitamins: thiamin,
    riboflavin, niacin, vitamin B-6, folate, vitamin B-
    12, biotin, and pantothenic acid
• Vitamins are abundant in fruits,
  vegetables, and grains; they are
  also added to some processed
• If you consume too much or too
  little of a particular vitamin,
  characteristic symptoms of excess
  or deficiency can develop
• It is best to obtain most of your
  vitamins from foods rather than
  Minerals- Inorganic Micronutrients
• Minerals = inorganic (non-carbon-containing)
  compounds needed in small amounts
  – for regulation, growth, and maintenance of body tissues
    and functions
• There are about 17 essential minerals:
  – Major minerals (those that the body needs in amounts
    exceeding 100 mg per day) include calcium,
    phosphorus, magnesium, sodium, potassium, and
  – Essential trace minerals include copper, fluoride, iodide,
    iron, selenium, and zinc
• If you consume too much or too little of a
  particular mineral, characteristic symptoms
  of excess or deficiency can develop
• Minerals commonly lacking in the American
  – Iron = low intake can cause anemia
  – Calcium = low intake linked to osteoporosis
  – Potassium = low intake linked to elevated blood
    pressure and bone mineral loss
  – Magnesium
       Osteoporosis - Thinning of Bones

• Dietary factors that build bone        • Dietary factors linked to
  mass:                                    loss of bone mass:
   –   Calcium                              –   Alcohol
   –   Vitamin D                            –   Sodium
   –   Vitamin K                            –   Caffeine
   –   Other possible dietary factors:      –   Retinol
       vitamin C, magnesium,                –   Soda
       potassium, manganese, zinc,          –   Protein (if intake of calcium
       copper, boron                            and vitamin D is low)
• Weight-bearing exercise and
  strength training also build and
  maintain bone mass
   Water - A Vital Component
• Human body is composed of about 50–60%
  – you can live only a few days without water
• Foods and fluids you consume provide 80–90%
  of your daily water intake
• Adequate intake to maintain hydration:
   – Women = about 9 cups of fluid per day
   – Men = about 13 cups of fluid per day
• Drink in response to thirst;
  – consume additional fluids for heavy exercise
      Other Substances in Food:
• Antioxidant
  – a substance that protects against the breakdown of body
    constituents by free radicals;
  – actions include binding oxygen, donating electrons to free
    radicals, and repairing damage to molecules
     • Free radical - a chemically unstable, electron-seeking compound
       that can damage cell membranes and mutate genes in its search
       for electrons
• Many fruits and vegetables are rich in antioxidants
  such as vitamin C, vitamin E, selenium, and
    Other Substances in Food:
• Phytochemical
  – a naturally occurring substance found in plant foods that
    may help prevent and treat chronic diseases
• Examples:
  – Certain proteins in soy foods
  – Sulforaphane in cruciferous vegetables (cabbage,
    broccoli, brussels sprouts, kale, cauliflower)
  – Allyl sulfides in garlic and onions
• Fruits and vegetables are rich in phytochemicals

         Nutritional Guidelines:
          Planning Your Diet
• Dietary Reference Intakes (DRIs)
  – standards for levels of nutrient intake to prevent nutrient
    deficiencies and reduce the risk of chronic disease
• Dietary Guidelines for Americans
  – general principles of good nutrition intended to help
    prevent certain diet-related diseases
• MyPyramid
  – a food-group plan that provides practical advice to
    ensure a balanced intake of essential nutrients

     Dietary Reference Intakes
• Set by the Food and Nutrition Board of the
  National Academies
• Recommended Dietary Allowance (RDA) or
  Adequate Intake (AI) = recommended intake
• Tolerable Upper Intake Level (UL)
  – maximum daily intake unlikely to cause health
• Example of calcium recommendations for an
  18-year-old woman:
  – RDA = 1300 mg/day
  – UL = 2500 mg/day
  Should You Take Supplements?
• The Food and Nutrition Board recommends
  supplements only for certain groups:
  – Folic acid for women capable of becoming
    pregnant (400 µg/day)
  – Vitamin B-12 for people over age 50 (2.4
• Other possible situations for supplements:
  – Vitamin C for smokers
  – Iron for menstruating women
  – Vitamin K for newborns
  – People with certain special health concerns
             Daily Values
• Daily Values
  – a simplified version of the RDAs used on
    food labels
• Also included in Daily Values are
  standards for nutrients with no
  established RDA
• Shown on food labels in terms of a
  2000-calorie diet

        Dietary Guidelines for
• Adequate Nutrients within Calorie Needs
  – Focus on nutrient dense foods.
  – Eat more dark green vegetables, orange
    vegetables, legumes, fruits, whole grains, and
    low-fat and fat-free milk and milk products.
  – Eat less refined grains, saturated fat, trans fat,
    cholesterol, added sugars, and calories.
  – Plans that meet the goals include MyPyramid
    and DASH.
       Dietary Guidelines for
• Weight Management
  – Evaluate body weight in
    terms of BMI.
  – Balance food intake and
    physical activity to avoid
    weight gain.
  – To lose weight, decrease
    calorie intake, maintain
    adequate nutrient intake, and
    increase physical activity.
Dietary Guidelines for
    • Physical Activity
      – 30 minutes per day to reduce
        risk of chronic disease
      – 60 minutes per day to prevent
        weight gain
      – 60-90 minutes per day to
        sustain weight loss

Dietary Guidelines for
      • Food Groups to
        – Fruits and vegetables—
          choose a variety of colors
          and kinds
        – Whole grains—half of all
          servings of grains should
          be whole grains
        – Low-fat and fat-free milk
          and milk products
     Dietary Guidelines for
• Fat Intake Goals
  – Total fat: 20-35% of total daily
  – Saturated fat: Less than 10% of total
    daily calories
  – Trans fat: As little as possible
  – Cholesterol: Less than 300 mg per
      Dietary Guidelines for
• Carbohydrate Intake
  – Choose high-fiber foods
  – Limit intake of added sugars
• Sodium and Potassium
  – Limit sodium intake
     • 2300 mg per day; 1500 mg per day for those at
       high risk
  – Consume adequate potassium
• Alcohol intake—moderate if at all

• Food guidance system that promotes
  healthy food choices and physical
• Choosing a balance of servings from
  different food groups meets nutrient
  needs and reduces chronic disease risk
• Balancing food choices and activity
  promotes weight management

          MyPyramid: Grains
• For a 2000-calorie diet
  – choose 6 ounce-equivalents per day
• 1 ounce-equivalent:
  – 1 slice of bread
  – 1 small muffin
  – 1 cup ready-to-eat cereal flakes
  – 1/2 cup cooked cereal, rice, grains,
  – 1 6-inch tortilla

MyPyramid: Vegetables
      • For a 2000-calorie diet,
        – choose 2-1/2 cups (5
          servings) per day
      • 1/2 cup or equivalent:
        – 1/2 cup raw or cooked
        – 1/2 cup vegetable juice
        – 1 cup raw leafy salad
      MyPyramid: Vegetables
• Choose vegetables from five groups:
  – Dark green vegetables
    • spinach, kale, collards, bok choy, other leafy
  – Orange and deep yellow vegetables
    • carrots, winter squash, sweet potatoes
  – Legumes
  – Starchy vegetables
    • corn, potatoes, peas
  – Others (e.g., tomatoes, bell peppers, green
    beans, cruciferous vegetables)
MyPyramid: Fruits
  • For a 2000-calorie diet,
    choose 2 cups (4 servings) per
  • 1/2 cup or equivalent:
    – 1/2 cup fresh, canned, or frozen
    – 1/2 cup fruit juice (100% juice)
    – 1 small whole fruit
    – 1/4 cup dried fruit
  • Choose whole fruits often
             MyPyramid: Milk
• For a 2000-calorie diet, choose
  3 cups or the equivalent per day
• 1 cup or equivalent:
  –   1 cup milk or yogurt
  –   1/2 cup ricotta cheese
  –   1-1/2 ounces natural cheese
  –   2 ounces processed cheese
• Choose low-fat and fat-free

   MyPyramid: Meat and Beans
• For a 2000-calorie diet, choose 5-1/2 ounce-
  equivalents per day
• 1-ounce equivalents:
  –   1 ounce cooked lean meat, poultry, fish
  –   1/4 cup tofu or cooked legumes
  –   1 egg
  –   1 tablespoon peanut butter
  –   1/2 ounce nuts or seeds
• Choose lean cuts, limit serving sizes, and try
  one plant protein source daily

  MyPyramid: Oils

• For a 2000-calorie diet, choose 6
  teaspoons per day
• 1 teaspoon or equivalent:
  – 1 teaspoon vegetable oil or soft margarine
  – 1 tablespoon salad dressing or light
  – Food sources: 8 large olives, 1/6 medium
    avocado, 1/2 tablespoon peanut butter, 1/3
    ounce roasted nuts
     The Vegetarian Alternative
• Types of vegetarian diets
   – Vegan
     • vegetarian who eats no animal products
  – Lacto-vegetarian
     • vegetarian who includes milk and cheese products
       in the diet
  – Lacto-ovo-vegetarian
     • vegetarian who includes milk and cheese products
       and eggs in the diet
  – Partial vegetarian, semivegetarian, or
     • vegetarian who includes eggs, dairy products, and
       small amounts of poultry and seafood in the diet
  Vegetarian Diets and Health

• Vegetarian diets
  – are lower in saturated fat and cholesterol
  – higher in complex carbohydrates, fiber,
    folate, vitamins C and E, carotenoids, and
• Nutrients of concern for vegetarians
  – vitamin B-12, vitamin D, calcium, iron, and

Dietary Challenges for Special
      Population Groups
• Women
  – nutrient density, calcium, iron
• Men
  – fruits, vegetables, grains
• College students
  – overall quality of food choices
• Older adults
  – nutrient density, fiber, vitamin B-12
• People with special health concerns
  – discuss with physician or dietitian
Food Labels
Read labels to
learn more
your food

Dietary Supplements
     • May contain powerful
       bioactive chemicals
     • Not regulated the way
       drugs are by the FDA in
       terms of testing and
     • May interact with
       prescription and over-the-
       counter drugs and
           Foodborne Illness
• Most caused by pathogens (disease-causing
• You can’t tell by taste, smell, or sight whether
  a food is contaminated
• To prevent foodborne illness
   – handle, cook, and store foods in ways that prevent
     microorganisms from spreading and multiplying
• New threat
   – bovine spongiform encephalopathy (BSE or “mad
     cow disease”)


• Cook foods to an
  appropriate temperate
• Keep hot foods hot
  and cold foods cold

    Organic Foods

• Organic
  • a designation applied to foods grown and
    produced according to strict guidelines
    limiting the use of pesticides, nonorganic
    ingredients, hormones, antibiotics, genetic
    engineering, irradiation, and other practices
• Organic foods tend to have lower levels of
  pesticide residues than conventionally
  grown crops

Food Additives
• Most widely used
  – are sugar, salt, corn syrup, citric acid,
    baking soda, vegetable colors,
    mustard, pepper
• Concerns about some additives:
  – Monosodium glutamate (MSG)
    causes some people to experience
    episodes of sweating and increased
    blood pressure
  – Sulfites cause severe reactions in
    some people
  – Check food labels
  Genetically Modified Foods
• GM organism
  – a plant, animal, or microorganism in which
    genes have been added, rearranged, or
    replaced through genetic engineering
• Many GM crops are already grown in
  the United States
  – soybeans, corn
• No labeling requirement unless a GM
  food contains a known allergen
            Food Allergies

• Reaction by the immune system to
  a food or food ingredient
• Common food allergens
  – peanuts, milk, eggs, tree nuts, soy,
    wheat, fish, and shellfish
• Severe allergic responses can
  include anaphylaxis

                     Food Intolerance
• More common than true food allergies
• Reaction to a food or food ingredient,
  – usually based on a problem with metabolism
• Common intolerances include lactose
  – in which people are deficient in the enzyme lactase,
    and gluten intolerance
• Problems can be avoided
  – by avoiding or limiting trigger foods
• Keep a food diary to help identify problems          67
   A Personal Plan: Applying
     Nutritional Principles
• Assess your current diet
• Set reasonable goals for change
• Try additions and substitutions to bring
  your current diet closer to your goals
• Adjust one meal or eating habit at a
• Plan ahead for challenging situations
         Web Site Resources
• American Dietetic Association:

• American Heart Association:

• FDA Center for Food Safety & Applied Nutrition:

• Gateways to Government Nutrition Information:
        Web Site Resources, con’t.
• Harvard School of Public Health Nutrition Source:

• Choose My Plate:

• National Cancer Institute:

• Tufts University Nutrition Navigator:

       Web Site Resources, con’t.

•   Pepsico:
•   Fast Food Facts:
•   My Fitness Pal:
•   Self Nutrition Data:


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