The Phytochemical Key to Health
by Brenda Davis, RD

Many phytochemicals are strong antioxidants, quenching destructive free radicals. Others have tremendous anticancer activity, blocking tumor formation, reducing cell proliferation and inducing enzyme systems that help rid the body of potent carcinogens. Phytochemicals also protect against cardiovascular disease by helping to reduce the formation of cholesterol, lower blood pressure, decrease blood cholesterol levels, decrease platelet stickiness, reduce blood clot formation, open blood vessels, and decrease damage to blood vessel walls.

Which foods are the most efficient phytochemical factories? Vegetables and fruits stand out as being particularly noteworthy, although legumes, grains, nuts, and seeds are also excellent sources. Among the most outstanding are dark greens (such as kale, collards and spinach), crucifers (like broccoli and broccoli sprouts) and, of course, garlic, tomatoes, blueberries, citrus fruits, flaxseeds and soybeans. Let’s take a look at some of the most impressive among these:

Kale: Found to have the greatest antioxidant activity when rated against 19 other vegetables, kale is rich in lutein, a phytochemical that protects the eyes from macular degeneration, the leading cause of blindness in North America. It’s also high in beta-carotene, (antioxidant), indoles (helps eliminate toxic compounds), sulforaphanes (anti carcinogens) and quercetins (anti-inflammatory agents).

Broccoli: With a similar complement of phytochemicals to kale, broccoli is also noted for its indole content (helping to shift estrogen production to a less potent form, a protective factor relative to hormone related cancers). Interestingly, broccoli sprouts contain anywhere from 10 to 100 times more sulforaphane than broccoli, comparing weight for weight.

Garlic: With a unique phytochemical makeup, garlic is loaded with allium compounds. These phytochemicals help to lower blood pressure, reduce the stickiness of blood cells, dilate blood vessels and destroy cancer cells. The allium compounds also have immune-stimulating, antibacterial, antifungal, antiyeast and antiasthmatic activity.

Tomatoes: Tomatoes get their red color from the exceptional amount of lycopene they contain. Lycopene has strong antioxidant properties and several studies have suggested that it may be effective in protecting against prostate cancer and/or slowing the growth of prostate tumors. There’s also some compelling evidence that lycopene is a powerful protector against the development of artery and heart disease.

Blueberries: In a study of over 40 vegetables and fruits by the USDA’s Center for Aging at Tufts University, the Oxygen Radical Absorbance Capacity, or ORAC (ability to quench free radicals) were tested. Blueberries came out on top! The primary active component in blueberries is a phenolic compound and powerful antioxidant called anthocyanin. This substance gives blueberries their rich blue color. Blueberries contain several other phenolic compounds, including flavonols and phenolic acids. In addition to their antioxidant activity, blueberries have been found to protect against urinary tract infections, improve “tired eyes,” and possibly reduce the overall effects of aging through their potent antioxidant activity.

Citrus fruits: A single orange contains over 170 different phytochemicals, including 60 flavonoids, 40 limonoids and 20 carotenoids. Flavonoids are strong antioxidants with significant anticancer and anticardiovascular disease activity, while limonoids help to reduce cholesterol levels and stimulate detoxifying enzymes.

Soybeans: These beans provide a rich plant source of protein and plant sterols, as well as phytoestrogens such as lignans and isoflavones. The principle isoflavones in soy are genestein and daidzein. These isoflavones are powerful antioxidants and very effective inhibitors of the tyrosine kinase enzyme—a potent tumor promoter. Research suggests that isoflavones may provide protection against heart disease, certain forms of cancer, and osteoporosis.

Flaxseeds: The champions of the nut and seed world, flaxseeds are our richest known source of lignans (potent anticarcinogens), with over 100 times the lignans of most other plant foods. They also boast the highest alpha-linolenic acid content of any food. Fifty-seven percent of the fat in flaxseeds is omega-3 fatty acids. Omega-3 fatty acids fight cancer and cardiovascular disease. Like other nuts and seeds, flaxseeds also contain flavonoids, phenolic acids, phytic acids, and tocotrienols (a type of vitamin E).

Green tea: With its polyphenol and catechin content, green tea is an

up and coming phytochemical superstar. It’s especially rich in epigallocatechin gallate, a potent anticarcinogen and powerful antioxidant.

It’s important to note that refining foods can dramatically diminish phytochemical content. Refining a grain of wheat removes 95% of the phytochemicals! Choosing a wide variety of colorful, whole plant foods is your key to a phytochemical-rich diet. Aim for a minimum of 7-10 servings of vegetables and fruits each day.

Brenda Davis, RD, is the co-author of "Defeating Diabetes, The New Becoming Vegetarian, Becoming Vegan, and Dairy-free and Delicious" (published by the Book Publishing Company), Brenda is an internationally acclaimed speaker, and is a past chair of the Vegetarian Nutrition Dietetic Practice Group of the American Dietetic Association. Brenda lives in Kelowna, Canada. For more info, please visit