Phytochemicals serve a wide variety of functions in plants to provide flavor, color but also to protect the plant from insects and microbes. More than 2000 of these chemicals have been identified. It has been known for 30 years that diets rich in fruits and vegetables are protective against some cancers and heart disease and for years vitamins and minerals were given the credit; now we know that more than likely it was the presence of the phytochemicals. Now there is evidence that these compounds may protect against macular degeneration, cataracts, type 2 diabetes, stroke, and hypertension.
Most phytonutrients work together, so it is nearly impossible to put them together in a pill; therefore, it is obviously recommended that foods rather than supplements provide them.
How do phytochemicals work? In general, they:
- Act as hormone-inhibiting substances that prevent the initiation of cancer.
- Serve as antioxidants that prevent and repair damage to cells due to oxidation.
- Block or neutralize enzymes that promote the development of cancer and other diseases.
- Decreases plague formation and formation of blood clots.
So what are some of them and where are they found?
- Indoles, isothiocyanates: Contain sulfur and may be protective against breast cancer. Found in broccoli, Brussels sprouts, cabbage, cauliflower.
- Terpenes: Limonene is from the same family of compounds as taxmoxifen (an anti- breast cancer drug). Found in oranges, lemons, grapefruit.
- Flavonoids (Include tannins, phenols): There are over 4000 of these. Gives red wines and dark teas their bitter taste. Found in apples, strawberries, grapes, green and black teas, red wine, purple grape juice, dark chololate.
- Carotenoids (alpha, beta carotenes, lutein, zeathanin, lycopene). There are more than 600 types that act as pigments in plants. Fat intake increases absorption. Found in dark green vegetables, orange, yellow and red vegetables and fruits.
- Capsasin: Affects blood clotting and clots; found in hot peppers.
- Curcumin: May inhibit enzymes that activate carcinogens. Found in turmeric, a yellow-colored spice.
- Resveratrol: Offsets artery-damage due to inflammation. Found in red wine, peanuts.
- Organosulfur compounds: May speed production of carcinogen-destroying enzymes or slow proliferation of carcinogen-activating enzymes. Found in chives, leeks, garlic, and onion.
- Protease inhibitors: May suppress enzyme production in cancer cells, slowing tumor growth; inhibit hormone binding; inhibit malignant changes in cells. Found in broccoli sprouts, potatoes, soybeans and other legumes.
- Tannins: May inhibit carcinogen activation and cancer promotion; act as antioxidants. Found in black-eyed peas, grapes, lentils, red and white wine, tea.
BOTTOM LINE: Until more research is done, eat real whole fruits and vegetables, NOT supplementary pills or extracts. By the way, taking antioxidant supplements have not been shown to be very effective if at all in disease prevention. These phytochemicals work together to protect us from disease, so taking one alone will probably have no effect on health or longevity.