PhytoNutrients? ~ [Issue 0799-4]
Jul 28, 1999 07:40 PDT
PHYTOCHEMICALS (PHYTONUTRIENTS) AND YOUR HEALTH
Based on the findings of several studies, the scientific community
has agreed that as much as 70% of preventable cancers and 33% of
cancer deaths are attributable to dietary factors. Some foods have
been identified as possible cancer promoters and cardiovascular
disease initiators; others appear to prevent disease.
Foods showing a protective effect against cancer and cardiovascular
disease include vegetables, grains, fruits, legumes and soybeans.
These foods also contain protective vitamins and phytochemicals.
Phytochemicals are various plant-produced compounds, some of which
provide the bright colors, flavors and aromas of plants. Other
compounds act as antioxidants or exhibit hormone-like actions in
plants and in people who consume them. "The rule of thumb is to
consume a lot of brightly colored fruits and vegetable products,"
says Mary Ellen Camire, Ph.D., Chair and Associate Professor at the
University of Maine.
"Natural pigments, such as chlorophyll, carotenoids and
anthocyanidins, appear to have some health benefits." Numerous
phytochemicals are known to exist, along with an accompanying list of
professed health benefits: increased activity of enzymes that
detoxify carcinogens; altered estrogen activity; and continued smooth
and strong artery linings, preventing attachment of cholesterol.
"There are hundreds of studies suggesting that a diet rich in fruits,
vegetables, grains and beans may lower the risk of some types of
cancer, heart disease and other chronic diseases. But precisely which
individual phytonutrient provides this protection is still far from
clear," says March A. Kantor, Ph.D., Associate Professor, Department
of Nutrition and Food Science, University of Maryland, College Park.
"Including lots of fruits and vegetables in your diet is a good idea,
based on so much research, which gets stronger every day, showing the
protective health effects of eating these foods," advises Marion
Nestle, Ph.D., Chair, Department of Nutrition and Food Studies, New
York University, New York City. Cruciferous vegetables-including
broccoli, cauliflower, cabbage and Brussels sprouts-contain indoles.
Indoles have been shown to reduce breast-cancer risk by preventing
estrogen overproduction, or by transforming the more cancer-promoting
types of estrogen-thereby also reducing the risk of other cancers.
The red, orange and yellow vegetables-carrots, squash, tomatoes,
beets and sweet potatoes-are rich in carotenoids and flavonoids. More
than 600 naturally occurring carotenoids exist. Of these, about 10%
act as precursors to vitamin A. To date, about 800 flavonoids have
been identified. Some of the more popular carotenoids protect against
heart disease, stroke and several cancers such as those of the lung,
breast, uterine, colon and prostate. Research indicates these
phytochemicals also lower cholesterol levels and enhance the immune
response. Tomatoes provide a rich source of lycopene, determined to
reduce the onset of prostate cancer. This carotenoid's beneficial
effects can only be obtained through diet or with supplements. Recent
studies show that tomato paste is the best source. "There are a lot
of promising studies being done on lycopene," says F. Jack Francis,
Professor Emeritus, Department of Food Science, University of
Massachusetts, Amherst. "However, I am not sure about its acceptance
just yet in the scientific community," Francis adds.
Thiols are found primarily in the alliums, including garlic,
scallions, leeks, onions and chives. Two popular phytochemicals in
this family are allyl sulfides and organo-sulfur compounds. These
compounds have been linked to lowered cholesterol levels, decreased
blood-clotting and some antibacterial functions.
Terpenes, limonene being the most common, are found primarily in the
rinds of citrus fruits, including lemons, grapefruits and oranges.
These phytochemicals help protect lung tissue, inhibit tumor growth,
and deactivate carcinogens. Many fruits also contain a form of a
potent phytochemical known as phenolic acid. Ellagic acid, a type of
phenolic acid, is found in strawberries and raspberries, and reduces
the damage caused by carcinogens like tobacco smoke.
Whole grains are rich in phenols, ligans, cumarins, phytosterols and
protease inhibitors - all which lower cholesterol. Recent research
has found that a diet rich in whole grains reduces the risk of cancer
by suppressing cell mutation, which blocks cancer-causing agents from
invading the body or slows progression of the disease. The American
Dietetic Association's position is that specific substances in foods
may have a beneficial role as part of a varied diet. "In the future,"
Francis says, "including phytochemicals in food products will have an
important nutritional value - the sky's the limit." - Food Product
Design; April 1998.