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Fruits and Vegetables – The Real Thing Matters! Being Fit with Phytochemicals Mollie Smith, MS, RD California State University, Fresno Department of Food Science and Nutrition Objectives What are phytochemicals? Where are they found? What are the health benefits? Are there any risks?

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fruits and vegetables the real thing matters being fit with phytochemicals

Fruits and Vegetables – The Real Thing Matters!Being Fit with Phytochemicals

Mollie Smith, MS, RD

California State University, Fresno

Department of Food Science and Nutrition

  • What are phytochemicals?
  • Where are they found?
  • What are the health benefits?
  • Are there any risks?
  • What are functional foods and how are they regulated?
  • What do we tell consumers?
definition of phytochemicals
Definition of Phytochemicals
  • Biologically active chemical compounds found in plants
  • Not nutrients like vitamins or minerals
  • Believed to have health benefits especially related to heart disease and cancer
Consumers often read exciting headlines about potential health benefits from eating foods that contain phytochemicals
    • Store shelves are overflowing with such supplements alongside functional foods whose labels often make fantastic claims for their health-promoting powers
how scientists view phytochemicals in foods
How Scientists View Phytochemicals in Foods
  • Some phytochemicals have profound effects on the body through actions such as
    • Acting as antioxidants
    • Mimicking hormones
    • Altering blood constituents in ways that may protect against some diseases
phytochemicals and functional foods
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
      • Some chemicals may exert different effects on different people or when taken at differing doses or at different life stages

Is More Better?

Choose Food First

Avoid Overdosing

Avoid Self Prescribing

phytochemicals and functional foods10
Phytochemicals And Functional Foods
  • Research on phytochemicals is in its infancy
    • What is current today will likely be challenged a year from now by further studies
  • In most cases, the health benefits observed with intakes of certain foods cannot be ascribed to individual phytochemicals
    • Much less to purified supplements of them
phytochemicals and functional foods11
Phytochemicals And Functional Foods
  • Currently, the evidence is insufficient to say with any degree of certainty whether any phytochemical is effective in fighting diseases or if it is safe to consume in concentrated doses
whole foods wine and tea
Whole Foods, Wine, and Tea
  • Epidemiological evidence spanning many countries indicates that deaths from cancer, heart disease, and heart attacks are less common where these foods are plentiful in the diet, where tea is a beverage, or where red wine is consumed in moderation
  • Whole Foods, Wine, and Tea
    • Historically, diets containing whole grains, fruits, vegetables, herbs, spices, teas, and red wines have been reputed to possess health-promoting qualities
    • These foods and beverages all have something in common
      • Phytochemicals of the flavonoid family
  • Many flavonoids act as antioxidants
    • May protect against cancers and heart disease by this mechanism
    • More evidence is needed before any claims can be made for flavonoids themselves as the protective factor in foods
      • Particularly when they are extracted from foods or herbs and sold as supplements
why are antoxidants important
Why are antoxidants important?
  • free radicals are molecules missing electrons: unstable
  • formation of 1 free radical causes a chain reaction with many free radicals formed
  • antioxidants prevent formation of free radicals or break the chain reaction by becoming oxidized
antioxidants con t
Antioxidants, con’t
  • Harmful effects from uncontrolled free radicals

• oxidation of lipids in cell membrane

• oxidation of DNA in cell nucleus

• ? cause of cancer

• ? cause of heart disease

• ? inflammatory diseases

• ? part of aging process

  • Because flavonoids often impart a bitter taste to food, food producers may refine away natural flavonoids to please consumers who generally prefer milder flavors
    • To produce white grape juice or white wine, makers remove the red, flavonoid-rich grape skins to lighten the flavor and color of the product
      • While greatly reducing its flavonoid content
  • Whether or not research confirms the cancer-fighting and heart-defending nature of flavonoids, consumers should seek out a variety of whole fruits, vegetables, and other plant-derived foods with their flavonoids intact in place of their more refined counterparts
    • Such diets are consistently associated with low rates of disease
  • Flavonoid supplements have not been proved effective or safe
  • As for red wine, the potential health benefits may not be worth alcohol’s immediate and substantial risk
  • Other sources:
    • Blueberries
    • Tea
    • Grapes
    • Vegetables
  • Black- most often sold, fermented and more processed
  • Oolong- semi-fermented, heated and dried more than green tea but less than black, served in Chinese restaurants
  • Green- unfermented, very little processing
  • White- unfermented, very little processing, harvested before leaves are fully open
  • Calorie Free
  • 87% of dietary flavonoids consumed
  • Antioxident polyphenols including flavonoids
    • Catechin
    • EGCG
    • Proanthocyanidins
tea s effect on heart disease
Tea’s effect on Heart Disease
  • Lower blood pressure
  • Lower cholesterol
  • Black tea may lower LDL cholesterol
  • Improved blood flow and blood vessel function
  • Protects against free radical damage
  • Decrease growth of abnormal cells
  • Associated with decreased risk of rectal, colon and skin cancer
other benefits
Other Benefits
  • Memory
  • Immune function
  • Oral health
  • Decreased risk of kidney stones
  • Obesity
  • Mostly epidemiological research and research on tea consumption, concentrated tea extracts may not be safe
  • Chocolate
    • Research subjects were instructed to eat three ounces of dark (bittersweet) chocolate chips
      • Flavonoid antioxidants from chocolate accumulate in the blood
        • The level of certain harmful oxidizing compounds dropped 40%
      • The antioxidant effects of dark chocolate may turn out to be as powerful as those of tea or red wine
  • In theory, chocolate may also “thin the blood” by reducing the tendency of blood to clot
    • Blood clots are a major cause of heart attacks and strokes
    • 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
    • Three ounces of sweetened chocolate candy contain over 400 calories
      • A significant portion of most people’s daily calorie allowance
    • Chocolate contributes few nutrients save fat and sugar
  • For most people, antioxidant phytochemicals are best obtained from nutrient-dense low-calorie fruits and vegetables and calorie -free green or black tea
    • With chocolate enjoyed as an occasional treat
  • Compared with people living in the West, Asians living in Asia suffer less frequently from:
    • osteoporosis
    • cancers, especially of the breast, colon, and prostate
    • heart disease
    • Asian women also suffer less from symptoms related to menopause
  • When Asians migrate to the U.S. and adopt Western diets and habits they experience these disease and problems at the same rates as native Westerners
  • Among many differences between the diets of the two regions
    • Asians consume far more soybeans and soy products such as miso, soy drink, and tofu than do Westerners
  • Soybeans contain phytochemicals known as phytoestrogens
    • Researchers suspect that the phytoestrogens of soy foods, their protein content, or a combination of these factors may be responsible for the health effect in soy-eating peoples
    • Research, though ongoing, is limited and inconsistent
  • We know with certainty that phytoestrogens are plant-derived chemical relatives of the human hormone estrogen
    • They weakly mimic or modulate the hormone’s effects on some body tissues
    • They act as antioxidants
  • We know that breast cancer, colon cancer, and prostate cancer are estrogen-sensitive
    • They grow when exposed to estrogen
    • It is unknown if actions of phytoestrogens may alter the course of estrogen-sensitive cancers
      • Results from recent breast cancer studies do not support the idea unless soy is consumed beginning in childhood
soybeans genistein
Soybeans: genistein
  • Symptoms of menopause
    • Phytoestrogens may reduce risk of adult bone loss and the sensation of elevated body temperature known as “hot flashes”
    • A diet high in soy may offer bone protection rivaling that of hormone replacement therapy (HRT)
    • May not reverse bone loss but may prevent it
  • 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
  • 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
heart disease
Heart Disease
  • 1999: FDA approved claim that 25 gm of soy protein per day may reduce your risk of heart disease
  • 2000: AHA endorsed soy as a heart healthy food
  • Research supports LDL lowering effect of soy, better effect in divided doses
  • 2006: AHA reevaluating endorsement due to conflicting research
  • Findings on the health effects of phytoestrogens should raise a red warning flag against taking supplements
    • Especially in women whose close relatives have developed breast cancer
  • Until more is known, a safer route to obtaining 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
make meat and poultry choices that are low fat or lean
Make meat and poultry choices that are low fat or lean
  • Choose a variety of types of protein foods including fish, dry beans and peas, nuts and seeds
  • Consider dry beans and peas as an alternative to meat or poultry
  • To provide a variety of nutrients in the diet including vitamin E while keeping saturated fat and cholesterol low

Historically, people have used flaxseed for relieving constipation or digestive distress

  • Currently, flaxseed and its oil are under study for potential health benefits
  • Contains lignans, compounds converted into biologically active phytoestrogens by bacteria that normally reside in the human intestine
  • Studies of populations suggest that women who excrete more phytoestrogens in the urine (an indicator of phytoestrogen intake from flaxseed and other sources) have lower rates of breast cancer
  • Animal studies show a decrease in tumors of the breast and lung when fed flaxseed
  • Studies of the direct effects of giving flaxseed to people are lacking
  • Some risks are possible with its use
    • Flaxseed contains compounds that may interfere with vitamin or mineral absorption
      • Thus high daily doses could cause nutrient deficiency diseases
    • Large quantities can cause digestive distress
  • Although no clear role has been established for flaxseed in the prevention of human cancer
    • Including a spoonful or two of flaxseed in the diet may not be a bad idea
    • Flaxseed richly supplies linolenic acid
      • A needed nutrient often lacking in the U.S. diet
choose most fats from sources of monounsaturated and polyunsaturated fatty acids
Choose most fats from sources of monounsaturated and polyunsaturated fatty acids
  • Keep the amount within calorie needs
  • Choose more fish, nuts and vegetable oils
  • Use lean meats and low fat dairy products
  • Limit saturated and trans fats
  • To provide essential fatty acids and vitamin E while keeping calories controlled and cholesterol and saturated fat low
  • People around the world 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
  • Among the phytochemical candidates for promoting this effect is lycopene
    • A red pigment with antioxidant activity
    • Found in guava, papaya, pink grapefruit, tomatoes (especially cooked tomatoes and tomato products), and watermelon
  • Lycopene may inhibit the reproduction of cancer cells
    • Some research suggests that low blood levels of lycopene and related compounds correlate with
      • increased risk of breast cancer
      • elevated incidence of heart disease, heart attack, and stroke
    • May also protect against the damaging sun rays that cause skin cancer
  • In one study, women who consumed a diet rich in fruits and vegetables had high lycopene concentrations and a greatly reduced concentration of an indicator of cervical cancer
  • Do scientists conclude that lycopene prevents cervical cancer? No.
    • The suggestion is that a diet rich in fruits and vegetables with their host of nutrients and phytochemicals reduces women’s risk of cervical cancer and many other diseases
  • A lesson about supplements can be learned from experience with lycopene’s chemical cousin
    • The normally beneficial vitamin A relative beta-carotene
  • Diets high in fruits and vegetables that contain beta-carotene often correlate with low rates of lung cancer
    • When beta-carotene supplements were given to smokers lung cancer rates increased
  • Descriptions of its uses for headaches, heart disease, and tumors are recorded in early Egyptian medical writings
  • In modern medical research, over 3,000 publications have investigated the potential health benefits of garlic
    • Many have reported positive findings
  • Among garlic’s active compounds are organosulfur compounds
    • Reported to inhibit cancer development in laboratory animals
    • suppress the formation of certain harmful oxidizing compounds that damage DNA and trigger cancerous changes
      • This evidence hints that eating garlic may be beneficial against some forms of cancer in human beings
  • More potential roles for garlic
    • allergies
    • heart disease
    • bacterial cause of ulcers
    • fungal infections
    • reduce the clotting of the blood
    • improve levels of blood cholesterol in people whose cholesterol is too high for heart health
  • Volatile sulfur compounds are not present as such in intact cells.
  • The reaction between
    • The enzyme allinase and
    • The volatile precursors
      • S-alk(en)yl cysteine sulfoxide and
      • Sulfonic acid

takes place when cells are ruptured

    • Results in the formation of
      • Different thiosulfonates and
      • Related sulfonic acid derivatives
  • Studies of garlic supplements, such as powders and oils, have been disappointing
    • Positive results seem to be associated with an aged preparation of garlic that lack garlic’s characteristic odor
      • But is rich in antioxidants and other compounds
    • From the scientist’s point of view, no evidence that large doses of concentrated chemicals from garlic may improve a person’s health or injure it
phytochemicals and functional foods59
Phytochemicals And Functional Foods
  • Supporters and Detractors of Phytochemical Supplements
    • Phytochemcials can alter body functions
      • Sometimes powerfully, in ways that are only partly understood
    • Evidence for the safety of isolated phytochemicals in human beings is lacking
regulation of phytochemicals and functional foods
Regulation of Phytochemicals And Functional Foods
  • 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 body’s structure or functioning
    • Research to support such claims may be weak
  • Researchers who study phytochemicals conclude that the best-known, most effective, and safest sources for phytochemicals are foods, not supplements
functional foods
Functional Foods
  • 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
functional foods62
Functional Foods
  • Cholesterol-Reducing Margarine, Juice, and Candies
    • Cholesterol is an indicator of an increased risk of heart disease
    • Replacing butter with ordinary liquid margarine in the diet may gradually lower blood cholesterol by a few percentage points over several months
      • Cholesterol-lowering medication takes just weeks to dramatically lower cholesterol by as much as 40%
functional foods63
Functional Foods
  • Regular daily uses of foods enhanced with sterol esters or stanol esters may reduce blood cholesterol 10%-15% over a relatively short time
functional foods64
Functional Foods
  • The sterol esters added to foods act like a drug in the body
    • Reports link high blood levels of these compounds with early signs of heart disease in people who have an inherited disability to clear them from the blood
    • May lower the blood concentration of some beneficial carotenes
      • Such as lycopene
functional foods65
Functional Foods
  • No one yet knows how these substances may affect children and teenagers
    • Yet children and teens may encounter them in the diet in the form of margarine, juice, and candies
who regulates what in the united states
Who regulates what in the United States?
  • FDA
    • Regulates safety and claims
  • FTC
    • Enforces consumer protection laws on advertising
  • USDA
    • Regulates label claims containing over a certain % of meat or poultry
nlea of 1990
NLEA of 1990
  • Mandates FDA to establish uniform nutrition labels
  • Establish when claims can be made
  • Allowed FDA-approved claims
  • FDA considers new health claims through rule-making
dshea of 1994
DSHEA of 1994
  • Amended labeling laws
  • Exempts dietary supplements
  • Permits use of structure-function claims
    • Without prior FDA approval
    • Must notify FDA 30 days after marketing
  • Must include the following disclaimer:
    • "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, mitigate, cure or prevent any disease"
dshea of 199469
DSHEA of 1994
  • Defines supplements
  • Sets criteria for regulating labeling
  • Defines dietary ingredient
    • Component of supplement
    • Not subject to previous additive laws
    • Distinct category of food material
dietary ingredient definition
Dietary Ingredient Definition

Dietary Ingredient

  • Vitamin
  • Mineral
  • Herb or other botanical
  • Amino acid
  • Any other ingredient used to supplement the diet
  • Metabolite, constituent, extract, concentrate of combination of these
structure function claim vs health claim
Structure-Function Claim vs. Health Claim

Functional Food

To modulate relevant target functions

Improvement of Metabolic

or Physiologic Process

Reduction of Risk of

Pathologic Process

Structured-Function Claim

Health Claim

what is a health claim
What is a Health Claim?
  • Characterizes the relationship of any substance to a disease or a health related condition
  • Uses terms “may” or “might”
  • Does not quantify the degree of risk reduction
  • Indicates disease depends on many factors
  • Framed within the context of the whole diet.
how are health claims approved
How are Health Claims Approved?
  • Approved by FDA through NLEA
  • Need extensive research
  • Are subject to a lengthy & costly review by FDA
  • Once authorized, ANY company can use it
  • Cannot be based solely on fortification
some health claims permitted
Some Health Claims Permitted
  • Calcium and decreased risk of osteoporosis
  • Sodium and increased risk of hypertension
  • Dietary saturated fats, cholesterol and increase risk of CHD
  • Dietary fat and increase risk of cancer
  • Fiber-containing grain products, fruits, vegetables and decrease risk of cancer
  • Fruits, vegetables, grain products containing fiber (soluble fiber) and decrease risk of CHD
  • Fruits, vegetables and decrease risk cancer
structure function claims
Structure-Function Claims
  • Include statements explaining how a substance affects the structure or function of the body (i.e. Calcium helps build strong bones)
  • According to DSHEA, must tell FDA within 30 days after first marketing
    • Permitted without prior approval
  • Cannot claim to decrease risk of disease
  • Disclaimer: “ This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure or prevent disease.”
safety of functional foods
Safety of Functional Foods
  • Unsafe products may reach the consumer
  • Products do not have safety information on labels
  • May not know extent of health problems
removal of new dietary ingredient
Removal of “NEW” Dietary Ingredient
  • Burden of Proof on FDA
  • Done in the courts
  • Inadequate information
functional foods78
Functional Foods
  • Is Every Food Functional?
    • Many functional foods occur in nature
      • A serving of broccoli sprouts provides a concentrated source of phytochemicals associated with cancer prevention
      • Drinking a half-cup of cranberry juice may reduce the incidence of urinary tract infections in women
phytochemicals and functional foods79
Phytochemicals And 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
  • All vegetables, fruits, and whole foods of every kind possess characteristic arrays of thousands of potentially healthful constituents
phytochemicals and functional foods80
Phytochemicals And Functional Foods
  • Even butter and cheese, foods known to contain fats damaging to the heart and arteries when eaten in excess, may qualify as “functional foods” by virtue of their content of conjugated linoleic acid (CLA)
    • In some animal studies
      • inhibits cancer
      • lowers cholesterol
      • improves diabetes
      • improves immune function
      • nudges body composition towards leanness
phytochemicals and functional foods81
Phytochemicals And Functional Foods
  • Virtually all foods have some special value in supporting health
phytochemicals and functional foods82
Phytochemicals And Functional Foods
  • Functional Food and Phytochemical Concerns
    • Large doses of purified phytochemicals added to foods may produce effects vastly different from those of phytochemicals in whole foods
phytochemicals and functional foods83
Phytochemicals And Functional Foods
  • Foods sold as functional foods often contain untested medicinal herbs
    • Such herbs have in recent years caused serious damage to health and even some deaths among consumers
    • Research has not matured enough to identify which isolated phytochemicals, medicinal herbs, or other constituents may appropriately be added to foods
      • Consuming these foods can be risky in unimaginable ways
phytochemicals and functional foods84
Phytochemicals And Functional Foods
  • One might also question the wisdom of dousing foods of low nutrient density with phytochemicals and then calling them “functional”
    • Implying that they will enhance health
  • Until research determines more about functional foods, consumers are on their own to make sure that the products they use are safe and effective
questions to ask
Questions to Ask
  • 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
questions to ask86
Questions to Ask
  • Has the FDA issued warnings about any of the ingredients?
    • Check the FDA’s 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
questions to ask87
Questions to Ask
  • Is the foods 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
phytochemicals and functional foods88
Phytochemicals And Functional Foods
  • When considering concentrated supplements of phytochemicals
    • Be aware that any normally beneficial substance, even water, can be toxic when taken in too high a dose
    • Though most naturally occurring substances are safe for most healthy people when consumed in foods
      • Virtually no safety studies exist to support the taking of any purified phytochemical
      • Nor have safe dosages been established
The Final Word
    • In light of all of the evidence for and against phytochemcials and functional foods
      • It seems clear that a moderate approach is warranted
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
phytochemicals and functional foods91
Phytochemicals And Functional Foods
  • Beneficial constituents are widespread among foods
    • Don’t 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
dietary guideline and food guide pyramid messages
Dietary Guideline and Food Guide Pyramid Messages
  • Plant based diet containing plenty of whole grains, whole fruits and vegetables
  • Color
  • Variety
  • Moderation
what do we tell consumers
What do we tell consumers?
  • Eat more fruit
  • Increase vegetable portions
  • Use herbs and spices
  • Replace some meat
  • Add grated vegetables
  • Try new foods