Protective Phytochemicals

Our health is greatly protected and our life may even be extended by a constant flow of antioxidants to our cells. Antioxidants include a large group of chemicals that act to fight and directly oppose oxygen charged molecules that are out to damage our cells. They work as a major police force of the body, and they are thought to divert most of the major diseases for which we are at risk. The free radicals have been suspected of involvement in heart disease, cancer, cataracts, and the aging process itself. Vitamins A, C, E, and beta carotene are the most well known of the antioxidants. There has been constant ongoing research on these vitamins over the last decade, and now we know more about them and their actions than ever before.

One of the most exciting areas of research into antioxidants has been done in the Age-Related Eye Disease Studies. In this study 3,640 people who already had macular degeneration took 500 mg of vitamin C, 400 IU of vitamin E, 25,000 IU beta carotene, 80 mg zinc and 2 mg copper. Subjects took all these, or a placebo every day for six years. The results from this study showed that the risk of advanced macular degeneration was cut by 25 percent in those who took the antioxidants plus zinc and copper. It is felt the study clearly provided strong evidence that antioxidants slow the progression in people who have the disease. This study prompted The Center for Science in the Public Interest (CSPI) in Washington, DC to make the recommendation that if you have advanced macular degeneration, you should take these antioxidants in the amounts given in the study and include zinc and copper, either as part of your daily multivitamin or in a separate supplement.

Supplemental antioxidants reduce the risk of prostate cancer. Middle-aged and older men should consider taking 200 mcg. of selenium and 400 IU of vitamin E per day, either as part of their daily multivitamin or in a separate supplement. Dietary and supplemental vitamin E is also effective in decreasing mortality from cardiovascular diseases. Everyone should be getting enough folic acid, vitamins B₁₂, D, and K, and other nutrients that are hard to get in a normal diet.

A deficiency of antioxidants can leave you very vulnerable, particularly if you are frequently exposed to toxic chemicals from cigarette smoke, industrial chemicals, or air pollutants. We can also increase our intake of antioxidants from food sources by eating more fruits and vegetables. Antioxidants are found in all plant foods, especially those that are brightly colored, with those that are deep green, bright yellow, orange, or red, being outstanding sources. Foods like tomatoes, oranges, broccoli, strawberries, carrots, greens, and other plant foods are also excellent choices. Remember to include a combination of at least five fruits and vegetables in your diet each day to increase the benefits of antioxidants in your diet.

A Rainbow of Protection

Pigmented plant compounds are important anti-inflammatory and antioxidant substances, and people who eat more of them have a decreased risk of cancer. Plant pigments are mostly polyphenolic, meaning they are multiphenol-containing molecules, and include chlorophyll, carotenoids and bioflavonoids.

Green plants contain particularly large amounts of chlorophyll, which is a detoxifier and possibly an anticancer agent. Foods rich in chlorophyll include chlorella and other blue-green algae, beet greens, bok choy, collards, dandelion greens, kale, mustard greens and nettles. These greens--among the most nutritious of all plants or plant parts--also contain other diverse nutrients and healthy constituents. The blue-green algae family has high chlorophyll content and has been credited with immune-enhancing effects including stimulation of phagocytosis and enhanced response to tumors and microbes. Chlorella powder, specifically, may reduce side effects of chemotherapy for some patients and may possess direct anticancer activities.

Orange, yellow and red-orange foods are rich in carotenoids such as beta-carotene, lutein and lycopene. These constituents are antioxidants and anticancer agents due to several different mechanisms. More than 600 carotenoids occur naturally, but carotenes are the most widely known. Carotenes seem to offer protection against lung, colorectal, breast, uterine and prostate cancers. Carotenes, which destroy oxygen free radicals in lipids, enhance immune response and protect cells against UV radiation. Foods rich in these flavonoids include apricots, carrots, citrus fruits, squash and tomatoes in addition to many green foods.

The anthocyanidins are a type of complex flavonoid that produce blue, purple or red colors. Foods rich in these phytochemicals include beets, blackberries, blueberries, cherries, purple and red grapes, and purple cabbage. Anthocyanidins support connective tissue regeneration and are anti-inflammatory; they promote blood flow and reduce cholesterol, in addition to being antioxidants. Anthocyanidins seem to stabilize and protect capillaries from oxidative damage and have been shown to stabilize connective tissue, promote collagen formation, improve microcirculation and help protect blood vessels from oxidative damage. Thus, by eating these antioxidant pigments, some believe cancer risk can be reduced because the antioxidants protect against damage and help repair connective and vascular tissues.

Proanthocyanidins are the precursors to anthocyanidins, and are comprised of smaller units including catechins and epicatechins. Catechins are simple flavonoids that are abundant in green tea. Several Japanese studies show that tea consumption is protective against breast and other types of cancer.

Phytochemical Defense

Detoxifying, stimulating and spicy sulfur compounds are present in a variety of colorful foods including broccoli, garlic and pineapple. Sulfur-containing compounds in plants are active, or at least protective, against cancer because many pathogens are deterred by sulfur. Sulfur compounds also chelate mercury out of the body.

The crucifer family--which includes broccoli, Brussels sprouts, cabbage, cauliflower, mustard greens, radishes and turnips--has many sulfur-containing compounds as well as indoles, a subclass of phytonutrients that binds chemical carcinogens and activates detoxification enzymes, mostly in the gastrointestinal tract. Indoles and related compounds may promote metabolism of carcinogens as well as improve estrogen balance, which could reduce the risk of estrogen-related cancers such as breast cancer.

The lily family includes garlic (Allium sativum) and onions (Allium cepa), both of which also contain sulfur compounds. Studies have shown the sulfur compounds diallyl disulphide and diallyl trisulfide--two of the active agents in garlic oil--and S-allyl cysteine--found in crushed garlic--to inhibit tumor metabolism and enhance immune response. Allyl sulfides also enhance glutathione S-transferase enzyme systems, which are biochemical pathways involved in the liver's detoxification of carcinogenic substances. Allium species also have immune-enhancing actions that include promotion of lymphocyte synthesis, cytokine release, phagocytosis and natural killer-cell activity.

Several animal studies have shown that garlic and onions prevent cancer and inhibit the progression of existing cancers, especially stomach and gastrointestinal cancers. Garlic appears particularly effective in reducing the risk of N-nitroso-induced cancers. N-nitroso compounds, also known as nitrosamines, are potent carcinogens formed within the intestines as a result of bacterial degradation of nitrates and nitrites, two common food chemicals used in the processing of ham, sausages and other meat products.

All forms of garlic have been shown to have some medicinal activity. Pineapples contain bromelain, a sulfur-rich proteolytic enzyme that has been investigated for antitumor effects. U.S. and French research shows oral bromelain can reduce cancer in animals. Some documented cases show cancerous tumors regressing as a result of bromelain therapy. Bromelain may also have antimetastatic effects. It has been examined in vitro to both oppose leukemia by promoting the normalization of blood cells and to reduce metastasis in lung-cancer cells.

Other protective phytochemicals include the caffeic, ferulic and ellagic acids, which have been shown to degrade carcinogenic substances. Among other things, caffeic acid helps degrade carcinogens, and ferulic acid helps prevent nitrates in the digestive tract from being converted into the carcinogenic nitrosamines. Caffeic and ferulic acids are found in green tea. Ellagic acid, which is particularly plentiful in pomegranates, also prevents carcinogen oxidation of cellular membranes. Ellagic acid is also found in blueberries, grapes, raspberries and strawberries.

Limonene is a bioflavonoid substance found in citrus rinds that stimulates both the glutathione transferase and the cytochrome p-450 liver detoxification systems. These enzymatic liver reactions break down carcinogenic substances in the body and help prevent them from damaging cellular DNA. Another bioflavonoid, quercitin, is ubiquitous in higher plants and has been widely studied for its antioxidant and concomitant anticancer actions.

Unexpected Allies

Whole-grain foods, rather than those derived from processed grains, are also worth emphasizing. Whole grains contain essential fatty acids (EFAs), which serve as precursors to prostaglandins and are important components of cell membranes.

Lignans, prominent in the woody parts of plants, are found primarily in rye and flax. They are believed to be converted by intestinal bacteria into enterolactone and enterodiol, which are absorbed across the intestinal walls where they travel to tissues and blood, binding with hormonal receptors. These weak estrogens may reduce excessive hormonal stimulation in tissues and reduce estrogen-related cancers. Fiber is also thought to reduce cancer risk by binding carcinogens in the intestines and making a favorable environment for beneficial bacterial flora. Fiber is acted upon by intestinal enzymes and microbes, yielding short chain fatty acids (SCFAs), which are noted to have anticancer effects. Coconut oil contains short chain fatty acids as well.

Genistein in red clover diminishes the growth of new blood vessels in cancerous tissues. Antitumor and anticancer properties also have been studied in mushrooms. Shiitake (Lentinus edodes) and reishi (Ganoderma ludidum) have been found to have general anticancer and immune-stimulating activity. Lentinan in shiitake mushrooms has been shown to be a potent immune potentiator. Maitake (Grifolia frondosa) also contains immune-stimulating polysaccharides.

Kelp and seaweed are also anticancer agents, rich in the mucilagenous alginates, which, like most fibers, gums and mucilages, swell in the intestines and absorb liquid as well as toxins and heavy metals. Alginates also may stimulate T-cell production and function since numerous other mucopolysaccharides have been shown to do this. Japanese studies show regular consumption of kelp reduces breast cancer risk. Kelp extracts have been highly successful in inhibiting laboratory cancer strains.

Cayenne pepper, ginger, rosemary, sage, thyme, turmeric and many others have anti-inflammatory, anticancer, immune-stimulating and antioxidant properties. Research suggests that curcumin, the bright yellow flavonoid present in turmeric (Curcuma longa) roots, selectively inhibits thromboxane production while sparing prostacyclin. Thromboxane is a potent inflammatory compound produced by the body in response to injury or irritation. It causes blood vessels to constrict and the blood to clot, while prostacyclin is an inflammatory mediator that can respond to tissue injury without leading to further inflammation. Inhibiting thromboxane prevents excessive inflammatory response and reduces damage to vascular endothelia. Curcumin has also been shown to inhibit tobacco smoke mutagenicity, suggesting it may help protect the vascular endothelia from damage caused by smoking.