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2002 Volunteer Leader Training Guide
Functional Foods: Foods That Protect Your Health
Handout 1
Scientific research has recently identified components in particular foods
that provide a health benefit beyond the traditional nutrients they contain. The
foods with these “added” health benefits have been termed functional foodsý In
addition, there are several other terms that have been coined to define these
foods. It is easy to be confused by the number of terms and the various
definitions that are used, sometimes interchangeably, in this emerging field.
The following definitions are currently commonly accepted.
Functional Food
This is a generic term for foods that have been linked to health benefits.
Although most research and food product development efforts have focused on
plant foods, several physiologically active components in foods from animal
studies are also being st died. Thus, functional foods can be from either plant
or animal sources. A food may be termed functional based on the ingredients
found naturally in it or added to it or based on ingredients that are products
of biotechnology (genetically-engineered).
Phytochemical/Phytonutrients
“Phyto” comes from the Greek word for plant. Phytochemicals are non-nutrient
plant chemicals that contain protective, disease-preventing compounds.
Phytochemicals are associated with the prevention and/or treatment of at
least four of the leading causes of death in the United States – cancer,
diabetes, cardiovascular disease and hypertension. Because most of the
components currently of interest for health maintenance and disease
prevention are found in plants, general terms like “functional foods” are
sometimes used interchangeably with "phytochemicals.” Phytochemicals are
sometimes called phytonutrients.
Nutraceutical
A nutraceutical is any substance that may be considered a food or part of a
food and provides medical or health benefits, including the prevention and
treatment of disease. Under this broad definition, nutraceuticals might be
isolated nutrients like vitamin E, dietary supplements of any kind,
processed foods, herbal products or genetically engineered foods. This term
can also be more restricted to only include isolated active compounds sold
as dietary supplements such as isoflavones.
Regulation
The regulation of functional foods can be quite confusing. Under the current
regulatory environment, functional foods or components can be placed into a
number of existing categories, including conventional foods, food additives,
dietary supplements, medical foods or foods for special dietary use. These
categories fall under the Federal Food, Drug and Cosmetic Act of 1938 (FDCA), as
amended. Implementing regulations falls under the U.S. Food and Drug
Administration (FDA).
Which Foods Are Good Sources of Phytochemicals?
More than 900 different phytochemicals have been identified as components of
food, and many more phytochemicals continue to be discovered. It is estimated
that there may be more than 100 different phytochemicals in just one serving of
vegetables. Some examples of vegetables in which phytochemicals have been found
include garlic, onions, broccoli, cauliflower, cabbage, Brussels sprouts,
spinach, turnips, tomatoes, peppers, carrots, celery and artichoke. Citrus
fruits (oranges, lemons, grapefruit) and other fruits such as grapes, berries,
cherries, apples, cantaloupe, watermelon and pomegranate have also been found to
have healthful phytochemicals. Phytochemicals can also be found in beans, grains
and seeds such as whole wheat, soybeans, oats, barley, brown rice and flax seed.
By consuming adequate servings of fruits and vegetables daily (5-9 servings) and
plenty of whole grains and seeds, one can reap the benefits phytochemicals
provide. Remember to balance plant foods with low-fat dairy foods and fish,
poultry and lean meat for the greatest benefit.
Arkansas-Grown Functional Foods
Of local interest to Arkansans is research underway at the University of
Arkansas. Investigators at the Institute of Food Science and Engineering are
trying to identify functional food components in the selected Arkansas food
products: blueberries, red grapes, watermelon, spinach and rice. Researchers
hope to learn which varieties of plants are the best sources of
phytochemicals and how the phytochemicals in these foods might help in the
prevention of chronic diseases by studying the health effects and biological
mechanisms involved in their metabolism.
Blueberries
Blueberries have been shown to provide numerous health benefits due to the
components found in them. These include anthocyanins, flavonols and phenolic
acids. These compounds are what give blueberries their color and act as
antioxidants.
Antioxidants act to protect the body against damage from oxidative stress, one
of several biological processes involved in aging and in the development of
a number of chronic diseases. Oxidation of lipoproteins in the blood
contributes to the development of atherosclerosis, the disease process that
leads to heart attacks and strokes. Scientists believe that antioxidants can
prevent lipoprotein oxidation and its biological effects. Antioxidants also
protect cells from damage that could lead to cancer.
Anthocyanins in blueberries protect against coronary heart disease and cancer,
lower cholesterol and prevent inflammation. Research has shown that
anthocyanins play an important role in preventing heart disease by acting as
antioxidants and by possibly inhibiting cholesterol absorption. The
flavonols are also pigments and are yellow in color. Flavonals have been
reported to protect against coronary heart disease, act as an antioxidant,
enhance one’s immune function, and act as an anti-inflammatory agent. Like
the other pigments in blueberries, phenolic acids act as antioxidants and
have also been shown to protect against coronary heart disease and cancer.
Red Grapes
The flesh of red grapes contains flavonols and anthocyaninsüwhich, like those
in blueberries, have antioxidant and anti-inflammatory properties, protect
against coronary heart disease and cancer and enhance the immune system. The
seeds of red grapes may be protective against coronary heart disease and
cancer, help to lower cholesterol and act as anti-inflammatory and
anti-viral agents.
Watermelon
Watermelon is another promising Arkansas crop. Watermelon contains carotenoids.
Carotenoids are a group of pigments in fruits and vegetables that include
alpha-carotene, beta-carotene, lycopene, lutein and many others. Their
colors range from colorless to red. Carotenoids act as antioxidants which
can help maintain healthy cells and tissues. The main carotenoid being
studied in watermelon is called lycopene. The lycopene in watermelon is
protective against coronary heart disease and cancer, and it enhances one’s
immune function. Lycopene is also present in tomatoes. Research has shown
that men who eat a lot of tomato products have a lower risk for prostate
cancer. Lutein is another carotenoid present in water-melon and may have
anticancer effects. Lutein is also being studied for its ability to protect
the retina in the eye.
Spinach
Spinach has been found to contain the carotenoids beta-carotene and lutein.
Like the carotenoids in watermelon, these pigments may be protective against
coronary heart disease and cancer, help to lower cholesterol, enhance immune
function and promote healthy vision. A recent study funded by the National
Eye Institute reported a connection between a diet rich in carotenoids,
especially leafy green vegetables such as spinach, and a reduced risk of
developing age-related macular degeneration, a blinding eye disease.
Rice
Research has shown that rice contains components called tocopherols that
protect against coronary heart disease and cancer, lower cholesterol, act as
antioxidants, protect DNA and enhance immune function. Rice also contains
phytosterols which protect against coronary heart disease, lower cholesterol
and act as antioxidants.
Another Functional Food of Interest
Soy
A functional food that is not part of the Arkansas study but is being studied
extensively for its functional properties is soy. Soyfoods are thought to
play a preventive role in heart disease, cancer, osteoporosis and may
alleviate menopausal symptoms. Isoflavones in soy are structurally similar
to estrogen and may act like weak estrogens in the body. It is in this
capacity that soy may exert its protective effect on estrogen-related
diseases such as breast cancer and osteoporosis.
While there are no magic foods that will make up for an otherwise poor diet or
other poor health behaviors, such as smoking or lack of exercise, eating
more functional foods may help protect you from developing certain diseases.
There are many beneficial components in functional foods. They may all work
together to protect your health. For this reason, it is better to eat the
foods rather than take supplements. Because supp²ements are not
well-regulated, they may not contain the phytonutrient in the active form,
they may not contain the phytonutrient at effective levels or even contain
it at all!
How can you get an adequate intake of phytonutrients to reap the health benefits
they provide? Eating a plant-based diet that is high in fiber, low in animal fat
and contains 5-9 servings of fruits and vegetables a day is recommended. Adding
low fat dairy products, especially those with active cultures, fish, poultry and
lean meat will balance your diet and provide the nutrients and protective
zoonutrients to help you be your healthiest.
Increasing the consumption of plant products containing phytonutrients in your
diet should not be difficult or time consuming. There are plenty of simple
strategies for increasing fruits, vegetables and whole-grains, including the
suggestions below:
- Keep fruits and vegetables stocked and in sight.
- Reach for 100% juice instead of coffee, tea or soft drinks.
- Add chopped fruit to cereal, yogurt, pancakes, muffins or even a
milkshake.
- Snack on fresh carrots, celery, broccoli, cauliflower and peppers.
- Add fresh greens, carrots, celery, parsley, tomatoes and/or beans to
your soups.
- Keep dried fruit for a quick snack at home or work.
- Choose more whole-grain cereals and grain foods instead of refined ones.
References:
Dresbach S.H., and A. Rossi, Phytochemicals – Vitamins of the Future?
Ohio State University Extension Fact Sheet.
Iowa State University Extension. 2000. What you need to know about…New food
words – phytochemicals, functional foods, and nutraceuticals.
Medders, H. 2001. “Let food be thy medicine and medicine thy food.” Arkansas
Land and Life. 6(2):8-9.
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