Phytochemicals are found in all plants, they protect the plants from bacteria, viruses, fungi and the ultraviolet of the sun; and they are healthy for us. More than 1,000 phytochemicals have been identified and more will be. There are 99 phytochemicals in wheat kernels alone.
The Different Types and Actions of Phytochemicals
Antioxidants: Most phytochemicals have antioxidant properties. Antioxidants protect our cells from oxidative damage. Oxidative damage to our cells is linked to many diseases including Alzheimer’s disease.
Oxidative damage is cause by too much oxygen. For example when you cut an apple and leave it out, exposing it to the oxygen in the air, it turns brown; that is oxidative damage. If you had put lemon juice on this cut-open apple, it wouldn’t have turned brown like that, because lemon is an antioxidant to the apple cells.
Oxidation sometimes produces what are known as free radicals that can cause damage to cells. When you hear of a "free radical scavenger", this means something that finds and gets rid of these free radicals. Oxidation is a normal process, so we need antioxidants to balance out this process. Free radicals can cause cancer, cardiovascular disease, macular degeneration, cataracts and Alzheimer’s disease. These phytochemicals keep us healthy from oxidation.

Healthy fruit and vegetables from farmers market. Photo by Whitney in Chicago
Flavonoids (bioflavonoids) are antioxidant phytochemicals. Some have as much as 50 times more antioxidant activity than vitamin C and E, and red grapes are more than a thousand times more powerful than vitamin E as an antioxidant. Flavonoids have been reported to have anti-viral, anti-inflammatory, anti-tumor, anti-allergic and anti-platelet benefits. Flavonoids are found in fruits, vegetables, wine, green tea, onions, apples, kale and beans. Here is a list of the more common flavonoid phytochemicals.

Healthy phytochemicals from berries. Winter squash soup and almonds. Photo: Shawn Henning
Other Phytochemicals
Indoles are phytochemicals that inactivate estrogens and stimulate the production of an enzyme that causes estrogen to be less effective reducing the risk of hormone-dependant cancer like some forms of breast cancer. Foods with these phytochemicals are the cruciferous vegetables including cabbage, radishes, broccoli, kale, Brussels sprouts, bok choy, turnips and cauliflower. These groups of phytochemicals are powerful cancer fighters.
Isoflavones are converted to plant estrogens (phytoestrogens) and may help to inhibit the growth of hormone-dependent cancers. An isoflavone from soy is genistein, which has anticancer and antioxidant properties and can only be found in soy foods such as miso, soymilk and tofu. They also help to protect us against heart disease, lower cholesterol, and to ease menopausal symptoms.
Phenolic Acids include capsaicin. This is the chili pepper family of vegetables. These can relieve symptoms of arthritis and improve flexibility. It also protects the stomach membranes and can protect against certain ulcers.
There are many other phytochemicals including alkaloids, coumestans, hydroxycinnamic acids, lignans, coumarins, curcumins, monophenols, monoterpenes, phytosterols, saponins, tritepenoids and xanthophylls that we get in all plants foods that are healthy for us.
Conclusion on Phytochemicals
Eating a variety of phytochemicals is what keeps us healthy. Phytochemicals are in all plants; in the roots, leaves, grains, grasses, spices, herbs, mushrooms, fruits and vegetables. The best way to be healthy is to eat a wide variety of edible plant foods and there are many ways to include plant foods and phytochemicals into every meal.
© 2009 Sam Montana
Sources
[1] J.A. Wylie-Rossett et al., “Influence of vitamin A on Cervical Dysplasia and Carcinoma In Situ,“ Nutrition and Cancer 6 (1984): 49-57; R.W.C. Harris et al, “Cancer of the Cervix Uteri and Vitamin A,” British Journal of Cancer 53 (1986): 653-659: K. Brock et al, “Nutrients in Diet and Plasma and Risk of In Situ Cervical Cancer, “Journal of the National Cancer Institute 80 (1988): 580-585
Linus Pauling Institute
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excellent excellent article
Thank you Steve and Carol. There is a lot to phytochemicals and more being learned all the time. Until this I didnt realize that there were so many. This is a great time of year now in late summer into fall to be eating all the fruits and veggies that have been growing all summer.
Lutein has long been known for it's affect on good eye health. Recently another benefit has come to light. Research just completed at Harvard concluded that it can also protect us from UVB light. This is the type of light which causes sunburn and skin cancer.
Nice job! This article is very clear and concise! Thanks!
Great article and detailed info. Phytochemicals see to be talked about a lot at Factoidz. I posted an article yesterday on Phytonutrients.