There are hundreds -- maybe even thousands -- of different phytochemicals contained in fruits and vegetables. Here's what some of them can do for your body:
- Allium (plant sulfurs), contained in onions and garlic, has been under investigation for its potential to reduce cholesterol levels and protect against heart disease. Studies have consistently shown that people who eat garlic have lower levels of LDL cholesterol (the "bad" form of cholesterol that contributes to the plaque build-up in atherosclerosis) than people who do not eat garlic. But garlic can also cause some unwanted side effects, such as bad breath, abdominal pain and flatulence. Also, cooking garlic may reduce some of its benefits.
- Ellegic acid, found in berries, may prevent healthy cells from turning cancerous. It may also protect the brain as it ages.
- Flavonoids are a part of a phytochemical family called polyphenols. There are more than 4,000 different flavonoids. The major categories of flavonoids are: flavones, flavonols, isoflavones, anthocyanins and catechins. Flavonoids are found in cranberries, onions, broccoli, kale, celery, soybeans, tomatoes, eggplant, cherries, apples, cranberries and tea. Red wine and grape juice contain a high level of phenolic flavonoids. Studies have shown that flavonoids can fight heart disease, slow cancer tumor growth, prevent blood clots, reduce inflammation and act as antioxidants. But in high doses, some flavonoids can cause serious gastrointestinal or allergic problems.
- Indoles are found in the cruciferous vegetables, including broccoli, cabbage, Brussels sprouts, cauliflower, kale, bok choy and turnips. Their primary benefit appears to be in protecting against certain forms of cancers. They may counteract carcinogens (cancer-causing agents) in the body, and they may play a role in blocking the growth of new prostate and breast cancer cells.
- Isoflavones (or phytoestrogens) are a type of flavonoid similar to the female hormone estrogen. They are found primarily in soy, but also in grains, berries, seeds and certain vegetables (such as chickpeas). Like estrogen, isoflavones can improve bone density and lower cholesterol levels, as well as reduce some of the symptoms of menopause. They may also protect against hormone-driven forms of cancer, such as prostate and breast cancer.
- Plant sterols, including sitosterol, stigmasterol and campesterol, have been investigated for their ability to lower cholesterol. A derivative of sitosterol is added to some cholesterol-lowering margarines and salad dressings.
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