Nutrition Tools Chapter 2

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Nutrition ToolsChapter 2

• Standards and Guidelines

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Introduction

• In practice, eating well proves harder than it
  appears
• Many people are overweight or undernourished or
  suffer from nutrient excesses or deficiencies
  that impair their health

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Nutrient Recommendations

• Nutrition recommendations are sets of yardsticks
  used as standards for measuring healthy peoples
  energy and nutrient intakes
• Nutrition experts use the recommendations to
  assess intakes and to offer advice on amounts to
  eat

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Nutrient Recommendations

• Standards in the U.S. and Canada are the Dietary
  Reference Intakes (DRI)
• A set of four values for measuring the intakes of
  healthy people
• Estimated Average Requirements (EAR)
• Recommended Dietary Allowances (RDA)
• Adequate Intakes (AI)
• Tolerable Upper Intake Levels (UL)

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Nutrient Recommendations

• The DRI committee has set values for
• Vitamins, Minerals, Carbohydrates, Fiber,
  Lipids, Protein, Water and Energy
• The DRI committee sets healthy ranges of intake
  for carbohydrate, fat, and protein
• 45-65 from carbohydrate
• 20-35 from fat
• 10-35 from protein

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Understanding the DRI Intake Recommendations

• The DRI committee has made separate
  recommendations for specific sets of people
• Men
• Women
• Pregnant women
• Lactating women
• Infants
• Children
• Specific age ranges

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Understanding the DRI Intake Recommendations

• The values are recommendations for optimal
  intakes, not minimum requirements.
• They include a generous margin of safety and
  meet the needs of virtually all healthy people.
• They assume that intakes will vary from day to
  day.
• They are designed for health maintenance and
  disease prevention in healthy people.

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How the Committee Establishes DRI Values -An RDA
Example

• To set an RDA for an essential nutrient
• Find out how much of that nutrient various
  healthy individuals need
• Review studies of deficiency states, nutrient
  stores and their depletion, and the factors
  influencing them

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How the Committee Establishes DRI Values

• Conduct is a balance study
• A laboratory study in which a person is fed a
  controlled diet and the intake and excretion of a
  nutrient are measured
• Are valid only for nutrients like calcium
  (chemical elements) that do not change while they
  are in the body

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How the Committee Establishes DRI Values

• Different individuals, even of the same age and
  gender, have different requirements
• If we look at enough individuals, we find that
  their requirements are distributed as shown in
  the following figure
• With most requirements near the midpoint
• And only a few at the extremes

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Setting Energy Requirements

• Estimated Energy Requirements (EER)
• The average dietary energy intake predicted to
  maintain energy balance in a healthy adult of a
  certain age, gender, weight, and level of
  physical activity with consistent good health
• Value is not generous
• Is set at the average of the populations
  estimated energy requirements
• Enough food energy to support health and life
• Too much energy causes unhealthy weight gain

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Why Are Daily Values Used on Labels?

• DRI values vary from group to group
• On a label, one set of values must apply to
  everyone
• The Daily Values (DV) reflect the needs of an
  average person
• One eating 2,000 - 2,500 calories a day
• Soon, the DV will be updated to reflect current
  DRI intake recommendations
• DV are ideal for allowing comparison among foods
• Because the DV apply to all people, they are much
  less useful as nutrient intake goals for
  individuals

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Think Fitness Recommendations for Daily
Physical Activity

• The American College of Sports Medicine (ACSM)
  makes these minimum suggestions to maintain a
  healthy body
• Engage in physical activity every day
• Exercise at a comfortable level
• Exercise for a duration of at least 30 minutes
  total per day
• For weight control and other health benefits, the
  DRI committee recommends 60 minutes of moderate
  activity each day

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Diet Planning with the USDA Food Guide

• Diet planning connects nutrition theory with the
  food we eat
• To help people achieve the goals set forth by the
  Dietary Guidelines for Americans 2005, the USDA
  provides a food group plan
• A diet planning tool that sorts foods into groups
  based on their nutrient content and then
  specifies that people should eat certain minimum
  numbers of servings of foods from each group

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How Can the USDA Food Guide Help Me to Eat Well?

• For most people, meeting the diet ideals of the
  Dietary Guidelines requires choosing more
• Vegetables
• Especially dark green vegetables, orange
  vegetables, and legumes
• Fruits
• Whole grains
• Fat-free or low fat milk and milk products
• And choosing less
• Refined grains
• Total fats
• Especially saturated fat, trans fat, and
  cholesterol
• Added sugars
• Total calories

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• The USDA Food Guide
• The USDA Food Guide teaches people to recognize
  key nutrients provided within the groups
• These are listed in the figure
• The figure also sorts foods within each group by
  nutrient density
• The foods within each group are well-known
  contributors of the key nutrients listed in the
  figure
• You can count on these foods to supply many other
  nutrients as well

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How Can the USDA Food Guide Help Me to Eat Well?

• Spices, herbs, coffee, tea, and diet soft drinks
  are excluded from the USDA Food Guide
• Provide few, if any, nutrients
• Can add flavor and pleasure to meals
• Can provide some potentially beneficial
  phytochemicals

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How Can the USDA Food Guide Help Me to Eat Well?

• Controlling Calories The Discretionary Calorie
  Allowance
• At each caloric level, people who consistently
  choose the most nutrient-dense foods may be able
  to meet their nutrient needs without consuming
  their full allotment of calories
• How Much Food Do I Need Each Day?
• The USDA Food Guide specifies the amounts from
  each food group needed to create a healthful diet
  at a number of caloric levels

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Conveying USDA Messages to Consumers

• The USDA makes applying its Food Guide easier
  through a graphic that depicts the highlights of
  the Food Guide Pyramid
• The new Food Guide Pyramid is in the textbook and
  on the internet at Mypyramid.gov
• A copy is on the next slide

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Conveying USDA Messages to Consumers

• The Pyramid demonstrates that fats and sugars are
  not typically nutrient-dense foods
• Their intakes should be limited
• It also conveys the idea that nutritious foods
  should be eaten in limited amounts to avoid
  excess calories and weight gain and overweight

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USDA Serving Equivalents versus Portions

• The trend in the U.S. has been toward consuming
  larger food portions
• Especially foods rich in fats and sugar
• Body weights have been creeping upward
• Suggesting an increasing need to control portion
  sizes

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USDA Serving Equivalents versus Helpings

• 1 cup refers to an 8-ounce measuring cup,
  filled to level
• Tablespoons and teaspoons refer to measuring
  spoons, filled to level
• Ounces signify weight, not volume

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Consumer Corner Checking Out Food Labels

• By law, a Nutrition Facts panel must list
  ingredients and details about a foods nutrient
  composition
• What Food Labels Must Include
• The common or usual name of the product
• The name and address of the manufacturer, packer,
  or distributor
• The net contents in terms of weight, measure, or
  count
• The nutrient contents of the product
• Nutrition Facts panel
• The ingredients, in descending order of
  predominance by weight

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Consumer Corner Checking Out Food Labels

• The Nutrition Facts Panel
• Most food packages are required to display a
  Nutrition Facts panel, like the one shown on the
  previous slide
• Grocers can post placards or offer handouts in
  fresh-food departments to provide consumers
  nutrition information for the most popular types
  of fresh fruits, vegetables, meats, poultry, and
  seafoods

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Consumer Corner Checking Out Food Labels

• Only the top portion of the panel conveys
  information specific to the food inside the
  package
• The bottom portion is identical on every label
• It stands as a reminder of the DVs (Daily Values)

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Consumer Corner Checking Out Food Labels

• The Daily Values are of two types
• Those for fiber, protein, vitamins, and most
  minerals suggest an intake goal to strive to
  reach
• Other daily values for cholesterol, total fat,
  saturated fat, and sodium, are daily maximums

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Consumer Corner Checking Out Food Labels

• What Food Labels May Include
• Nutrient claims on food labels
• If a food meets specified criteria, the label may
  display certain approved nutrient claims
  concerning the products nutritive value

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Consumer Corner Checking Out Food Labels
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Consumer Corner Checking Out Food Labels
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Consumer Corner Checking Out Food Labels
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Consumer Corner Checking Out Food Labels
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Controversy Phytochemicals And Functional Foods
What Do They Promise? What Do They Deliver?

• Functional Food
• No official U.S. definition but used to
  describe foods with beneficial effects beyond
  providing nutrients
• Phytochemicals
• Biologically active compounds of plants
  believed to confer resistance to diseases

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Controversy Phytochemicals And Functional Foods
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Controversy Phytochemicals And Functional Foods

• Some Cautions
• Foods consist of thousands of different chemicals
• Each has the potential of being beneficial,
  neutral, or harmful to the body
• Some may be beneficial in some ways and harmful
  in others
• Research on phytocehmicals is in its infancy
• What is current today will likely be challenged a
  year from now by further studies

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Controversy Phytochemicals And Functional Foods

• When considering concentrated supplements of
  phytochemicals
• Be aware that any substance, even water, can be
  toxic in too high a dose
• Most naturally occurring substances are safe for
  most healthy people when consumed in foods
• However, no safety studies exist to support the
  taking of any purified phytochemical
• No safe dosages have been established
• How Scientists View Phytochemicals in Foods
• Mimic hormones
• Act as antioxidants
• Alter blood constituents in ways that may protect
  against
• some diseases

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Controversy Phytochemicals And Functional Foods

• Whole Foods, Wine, and Tea
• Diets containing whole grains, fruits,
  vegetables, herbs, spices, teas, and red wines
  have been thought to have health-promoting
  qualities
• Epidemiological evidence shows that deaths from
  cancer, heart disease, and heart attacks are less
  common when these foods are plentiful in the
  diet.
• These foods contain phytochemicals of the
  flavonoid family---examples are on the next slide

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Controversy Phytochemicals And Functional Foods

• Many flavonoids act as antioxidants
• May protect against cancers and heart disease
• More research is needed before any definite
  claims can be made for flavonoids
• Particularly when they are extracted from foods
  or herbs and sold as supplements
• Flavonoid supplements have not been proved
  effective or safe
• The potential health benefits of red wine may not
  be worth alcohols risks

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Controversy Phytochemicals And Functional Foods

• The flavanoids in chocolate may thin the blood
  by reducing the tendency of blood to clot
• Clots are a major cause of heart attacks and
  strokes
• So far no evidence exists to indicate that people
  who eat chocolate suffer fewer heart attacks or
  strokes than people who do not
• Chocolate consumption promotes weight gain
• Chocolate contributes few nutrients besides fat
  and sugar

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Controversy Phytochemicals And Functional Foods

• Soybeans contain phytoestrogens
• Asians consume a lot of soybeans and soy products
  such as miso, soy drink, and tofu
• Asians living in Asia compared with people living
  in the West suffer less from
• osteoporosis
• Cancers --breast, colon, and prostate
• heart disease
• Asian women also suffer less from symptoms
  related to menopause
• When Asians adopt Western diets and habits they
  experience these disease and problems at the same
  rates as Westerners

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Controversy Phytochemicals And Functional Foods

• Phytoestrogens are plant-derived chemical
  relatives of the human hormone estrogen
• They weakly mimic the hormones effects on some
  body tissues
• They act as antioxidants
• Breast cancer, colon cancer, and prostate cancer
  are estrogen-sensitive
• They grow when exposed to estrogen
• It is not known if actions of phytoestrogens
  alter the course of estrogen-sensitive cancers
• Results from recent breast cancer studies do not
  support the idea
• Because HRT involves some serious health risks,
  supplements of soy are often sold to menopausal
  women as a natural alternative
• Research does not support taking phytoestrogen
  supplements for bone mineral retention or hot
  flashes

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Controversy Phytochemicals And Functional Foods

• Phytoestrogen supplement use may involve some
  risk
• While studying one soy phytoestrogen, genistein,
  researchers found that instead of suppressing
  cancer growth, high doses appeared to speed
  division of breast cancer cells in laboratory
  cultures and in mice

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Controversy Phytochemicals And Functional Foods

• Female offspring of mice treated with high doses
  of genistein during pregnancy were prone to
  developing cancer of the uterus
• Pregnant women should never take unproven
  supplements of any kind
• Until more is known, a safer way to obtain soy
  phytoestrogens is to include moderate amounts of
  soy-based foods in the diet
• As generations of Asian people have safely done
  through the ages

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Controversy Phytochemicals And Functional Foods

• Flaxseed contains lignans
• Compounds converted into biologically active
  phytoestrogens by bacteria in the human intestine
• In lab experiments with rats tumors are reduced
  with chow high in flax seed
• Clinical studies with humans are few
• Tomatoes contain lycopene
• A red pigment with antioxidant activity
• Studies show people who eat the most tomatoes,
  about 5 tomato-containing meals per week, are
  less likely to suffer from cancers of the
  esophagus, prostate, or stomach than those who
  avoid tomatoes

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Controversy Phytochemicals And Functional Foods

• Lycopene may inhibit the reproduction of cancer
  cells
• Some research suggests that an increased risk of
  breast cancer may follow low blood levels of
  lycopene and related compounds
• Low blood lycopene also correlates with an
  elevated incidence of heart disease, heart
  attack, and stroke
• Lycopene may also protect against the damaging
  sun rays that cause skin cancer

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Controversy Phytochemicals And Functional Foods

• Garlic
• Over 3,000 publications have investigated the
  potential health benefits of garlic
• Investigations into the potential roles for
  garlic against allergies, heart disease, and the
  bacterial cause of ulcers are ongoing
• Some compounds in garlic may fight fungal
  infections, reduce the clotting of the blood, or
  improve levels of blood cholesterol
• Other constituents of garlic also seem promising
  in promoting heart health
• Studies of garlic supplements, such as powders
  and oils, have been disappointing

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Controversy Phytochemicals And Functional Foods

• Detractors of Phytochemical Supplements
• The ways phytochemcials can alter body functions
  are only partly understood
• Evidence for the safe use of isolated
  phytochemicals in human beings is lacking
• No regulatory body oversees the safety of
  phytochemicals sold to consumers
• No studies are required to prove that they are
  safe or effective before marketing them
• Phytochemical labels may make claims about
  contributing to the bodys structure or
  functioning
• Research to support such claims may be weak
• The most effective, and safest sources for
  phytochemicals are foods, not supplements

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The Concept of Functional Foods

• Manufacturers have taken this concept a step
  further by adding phytochemicals and other
  substances perceived to be beneficial to foods
• Not long ago, most of us could agree on what was
  a food and what was a drug
• As these new foods come to market, this
  distinction is becoming less clear

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The Concept of Functional Foods

• Regular daily uses of foods (margarine) enhanced
  with sterol esters or stanol esters may reduce
  blood cholesterol 10-15 over a relatively short
  time
• The sterol esters added to foods act like a drug
  in the body
• Reports link high blood levels of sterol esters
  with early signs of heart disease in people who
  have an inherited disability to clear them from
  the blood
• They lower the blood concentration of some
  beneficial carotenes as lycopene
• No one yet knows how these substances may affect
  children and teenagers
• They may consume them in the form of margarine,
  juice, and candies

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The Concept of Functional Foods

• Yogurt A functional food
• Contains living Lactobacillus or other bacteria
• Such microorganisms, or probiotics, are believed
  to alter the native bacterial colonies or other
  conditions in the digestive tract that may
  reduce diseases
• May be useful for improving the diarrhea that
  often occurs from the use of antibiotic drugs or
  other causes
• More research is needed to verify suggestions
  that probiotic preparations may
• alleviate lactose intolerance and allergies
• enhance immune function
• protect against digestive tract cancers
  (particularly colon cancer) and ulcers
• reduce urinary and vaginal infections in women
• lower blood cholesterol

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The Concept of Functional Foods

• Cooked tomatoes provide lycopene along with
  lutein (an antioxidant associated with healthy
  eye function), vitamin C (an antioxidant
  vitamin), and may other healthful attributes
• Lutein also occurs in leafy greens
• Along with other phytochemicals and beneficial
  nutrients
• All vegetables, fruits, and whole foods of every
  kind possess characteristic arrays of thousands
  of potentially healthful constituents

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The Concept of Functional Foods

• Functional Food Concerns
• Large doses of purified phytochemicals added to
  foods may produce effects different from those
  in whole foods
• cranberry tablets may increase risk of developing
  kidney stones instead of providing the bladder
  benefits of cranberry juice

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The Concept of Functional Foods

• Does it work?
• Well-controlled, peer-reviewed research is
  generally lacking or inconclusive for
  manufactured functional foods
• Is it safe?
• Check the research for well-controlled safety
  studies
• The active ingredients of functional foods may
  cause allergies, drug interactions, dizziness, or
  other side effects
• Until research determines more about functional
  foods, consumers are on their own to make sure
  that the products they use are safe and effective

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The Concept of Functional Foods

• Has the FDA issued warnings about any of the
  ingredients?
• Check the FDAs MEDWATCH web site or call the FDA
  to find out
• How much of what does it contain?
• Manufacturers are required to list the names of
  added herbs and phytochemicals on labels
• But not the quantities added
• Beware, especially, of combinations of
  functional ingredients

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The Concept of Functional Foods

• Is the food in keeping with the Dietary
  Guidelines for Americans?
• A candy or brownie or smoothie shake may be
  fortified with herbs and phytochemicals but is is
  still made mostly of sugar and fat
• People who eat the recommended amounts of a
  variety of fruits and vegetables may cut their
  risk of many diseases by as much as half
• Replacing some meat with soy foods or other
  legumes may lower heart disease and cancer risks
• In the context of a healthy diet, foods are
  time-tested for safety, posing virtually no risk
  of toxic levels of nutrients or phytochemicals

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Controversy Phytochemicals And Functional Foods

• Phytochemicals are widespread among foods
• Dont try to single out one phytochemical for its
  magical health effect
• Take a no-nonsense approach where your health is
  concerned
• Choose a wide variety of whole grains, legumes,
  fruits, and vegetables in the context of an
  adequate, balanced, and varied diet