Study after study has found that people whose diets contain a lot of fruits and vegetables are significantly healthier than those whose diets contain few. While most produce is packed with vitamins and minerals, they are not the only nutritional components responsible for fighting disease.
In recent years, research has begun to focus on the phytochemicals (phyto=plant) they contain. These naturally occurring plant compounds, which are not found in animal-based foods, may help the body fend off heart disease, diabetes, and cancer. The following are a few of the most intensely studied.
These compounds are produced in vegetables of the cruciferous family, including cabbage, broccoli, and brussels sprouts. Several studies have found that indoles can delay the onset of tumors and even prevent the formation of malignancies. They are believed to work, in part, by stimulating enzymes in the body that defuse carcinogens before they have a chance to cause harm.
Found mainly in soy, soy products, and red clover, isoflavones are estrogenlike substances, also known as phytoestrogens, that may block breast cancer, lower cholesterol, slow bone loss, and ease the symptoms of menopause, especially hot flashes. Isoflavones may also be responsible for the decreased incidence of breast, colon, and prostate cancers in populations that regularly consume soy foods.
Studies have also found that postmenopausal women who take isoflavone supplements have more supple arteries, allowing blood to flow freely and thus theoretically lowering the risk for heart disease. After carefully considering several studies, The Food and Drug Administration has even decided that soy protein, which contains isoflavones, can lower blood cholesterol.
The official word from the FDA is that diets that contain at least 25 grams (g) of soy protein a day -- as part of a diet low in saturated fat and cholesterol -- might reduce the risk of heart disease. A proposal is now being considered by the agency that will allow foods containing a minimum of 6.25 g of soy protein per serving to make a cholesterol-lowering claim on the label.
The two main isoflavones believed to be responsible for soy's amazing range of health benefits are daidzein and genistein. These phytoestrogens have weak estrogen-like effects and can take the place of more potent estrogens in the body; in essence, they act as anti-estrogens. In addition, genistein is a proven antioxidant -- another characteristic that may contribute to its potential as a cancer fighter.
Researchers point to the fact that in Asian countries, where consumption of isoflavone-rich soy is high, the incidence of breast and prostate cancer is low. The average isoflavone intake throughout Asia is about 25 to 45 milligrams (mg) a day. In Japan, estimates have gone as high as 200 mg a day. In the United States and other Western countries, however, the average daily intake is only about 5 mg a day.
For postmenopausal women who can't or choose not to take estrogen replacement therapy, isoflavone supplements may be a reasonable alternative, though experts aren't 100 percent sure of their long-term safety. They do offer one distinct advantage -- unlike estrogen replacement therapy, they do not increase the risk of uterine cancer.
A dose of 50 to 100 mg of isoflavones a day may be enough to offer the same health benefits as estrogen replacement therapy, but no one knows exactly how much isoflavones it takes to provide the same effect.
Also, bear in mind that if you've recently upped your intake of soy foods or soy-based supplements, you're already getting supplemental isoflavones. Don't take isoflavone supplements if you're already taking estrogen replacement therapy without checking first with your doctor. The same holds true if you're taking prescription drugs for the prevention of breast cancer or osteoporosis.
Before you start seeking soy, be aware that soy products contain oligosaccharides, a type of sugar that your body can't digest and that causes gas and bloating. Not everyone is affected. But if you're not used to soy, take it easy in the beginning to allow your body time to adjust. For the future, look for soy products made from low-oligosaccharide soy. They're in the works.
This group of phytochemicals has weak estrogen and anti-estrogen effects that may change the actions of sex hormones, such as estrogen and testosterone. Flaxseeds from the flax plant (Linum usitatissimum) are the richest source. You won't find much in flaxseed oil, however, since lignans are removed during processing.
Lignans are also found in small amounts in barley, buckwheat, millet, oats, legumes, broccoli, carrots, cauliflower, and spinach. It should come as no surprise, then, that vegetarians tend to have higher levels of lignans in the body than meat-eaters. Populations with high-fiber diets and high intakes of phytoestrogens such as lignans tend to have lower rates of hormone-dependent cancers such as breast cancer than Western populations with low fiber intakes.
The plant lignans in flaxseed are converted by the bacteria in the colon to mammalian lignans, which may protect against hormone-sensitive cancers by inhibiting certain enzymes involved in hormone metabolism, reducing estrogen levels and interfering with tumor growth. The lignans in flaxseed and other plants are actually converted into a different form of lignans in the colon by the bacteria that normally reside there.
The name gives it away. This compound is a natural component of oil from citrus fruits like lemon, but it is also found in oils from mint, caraway, thyme, cardamom, and coriander. It is one of a group of phytochemicals known as terpenes and is commonly used as a flavor and fragrance.
It has been intensely studied for its ability to suppress cancer and has been found to cause complete reversal of breast cancer in animals and inhibit the growth of skin cancer. Limonene is believed to fend off cancer by activating cancer-fighting enzymes naturally produced by the body. There are actually about 40 limonoid compounds found in citrus fruits, all of which may be involved in the fight against cancer.
Purple grapes are your richest source of this heart-healthy phytochemical. Research from Holland has hinted that resveratrol may be the reason that those who drink red wine every day have a lower risk of heart disease. Resveratrol appears to have anticancer effects as well. If you want the resveratrol without the alcohol, go for purple grapes or purple grape juice. They're concentrated sources, too.
The active ingredient in aspirin and a common additive in foods, this compound is also found in several fruits and vegetables, such as prunes and raisins. It's believed to mimic the anticlotting effects of the chemically related aspirin, which is routinely prescribed to prevent heart attacks. Research suggests it may also reduce the risk of cancer.
SulforaphaneThis phytochemical is found in broccoli, cauliflower, brussels sprouts, and cabbage -- foods that have long been known as cancer fighters. A few years ago, researchers at Johns Hopkins University School of Medicine uncovered a clue as to why. It seems that when sulforaphane jump-starts the activity of protective, detoxifying enzymes in the body, it disarms carcinogens, lowering the risk that cancer cells will develop.
Continue to the next page to learn about anti-aging supplements for seniors ranging from alpha-liopaic acid to MSM.