Chemopreventive Nutrition

Within the last decade there has been a multitude of studies published on the rediscovering of natural medicine. The results are encouraging as science finds new ways to redefine treatment while reassessing the condition itself. As this quest continues so does the growth rate of disease. One of the largest growing plagues is what is commonly referred to as the BIG C. Fortunately, a promising area of research is the exploration of how vitamins, minerals and botanicals can help reduce the risks of this mysterious predator. Studies conclude that taking nutritional supplements may effectively reduce the risk of cancer. Whole foods contain many of the recommended nutrients the body needs. Only a mere 10% of US population, however, actually consumes the recommended 5 servings of fruits and vegetables daily. Actually, 20-35% of the U.S. population consumes the levels of fruits and vegetables that put them in the "low consumption" category. It is speculated that the low consumption group is two times as likely to get cancer as the 10%, which get the full 5 servings.
(Goodwin JS and Brodwick M, 1995)

Antioxidants are the group of nutrients, which are in the spotlight of preventive nutrition research. Studies show that this group of vitamins is excellent for protection against cellular damage, and further trials are being conducted on their ability to treat certain types of malignancies. The most popular antioxidants include beta-carotene, vitamin E, vitamin C, and the mineral selenium.

Carotenoids have been found to interfere with carcinogenesis and are safe, non-toxic nutrients for prevention. Numerous studies have been conducted on the effects of beta-carotene, alpha-carotene, lutien, lycopene and cryptoxanthin. (Poppel, 1993) In Japan, a cohort study conducted on 2,300 women and for 3-6 years found that those with high levels of beta-carotene had a "significantly lower risk of dying from cancer." (Langseth, 1995) There are three mechanisms by which beta-carotene may work – as a compensator, protector, and immunomodulator. As a protector, it is believed that natural conversion of beta-carotene to vitamin A takes place in the body. This action is believed to help compensate for the levels of vitamin A, which are decreased by carcinogenesis. Another mechanism, which takes place, is the antioxidant protection against free radical attack on DNA. Lastly, beta-carotene is an immunomodulator, which can quench free radicals, lower immuno-suppressing lipid peroxides, alter arachadonic metabolism, and protect cellular structure. (van Poppel & van den Berg, 1997)

Vitamin E is the antioxidant, which has been making newspaper headlines lately. It is a lipid-soluble antioxidant, and it is virtually impossible to achieve chemopreventive levels from a typical western diet. There has been a direct association of low levels of vitamin E and cancer patients. The mechanisms of the tocopherols include blockage of nitrosamine formation and assisting the natural production of antibodies. (van Poppel & van den Berg, 1997) A review in the July 16,1997 issue of the Journal of the National Cancer Institute reviews the benefits of alpha and gamma tocopherols on the second most common cause of cancer deaths—colon cancer.
The paper discusses how tocopherols inhibit oxidation, which may make tocopherols (alpha as well as others) key in preventing colon cancer.
(Stone & Papas, 1997)

The administration of vitamin C is also being explored for its chemopreventive properties. As a cell protector, vitamin C is essential. Thousands of studies support the supplementation of vitamin C and explain the myriad of benefits this vitamin offers. Ascorbate at high doses has also been found to protect cells from oxidative stress, which predisposes malignancy. For treatment of malignancies, it has proven beneficial in the stomach and the liver by assisting in the production of enzymes for detoxification—an essential part of protection from carcinogen formation.
(van Poppel & van dan Berg, 1997)
In some cases, high doses of vitamin C have been shown to inhibit the progression of certain tumors. Studies have suggested that in order to achieve maximum benefits from vitamin C as well as the other antioxidants, supplementation should consist of a combination of the antioxidant nutrients rather than administering them individually. (Prasad & Kumar, 1996)

Selenium is a mineral, which also offers remarkable protection against oxidative damage. Years of research support the use of selenium to prevent some form of cancer. A recent study published in the Journal of the American Medical Association (JAMA) found that selenium may help to reduce the progression of carcinomas in several different sites. (Clark et al., 1996) Another study, conducted in the Qidong Providence of China, concluded that selenium supplementation of 200 mcg. Per day for two years significantly decreased the incidence of one of the most common diseased found in the southern region of China—hepatoma. (Han, 1993)

Herbal Protection

Botanicals and plant medicine are another area of scientific exploration of chemopreventive nutrients. Green tea, karawatake mushroom, garlic and soy are four focuses of research, which have displayed important roles in prevention. Green tea is one of the most popular beverages in Asia, where it has been used as a medicine for over 4,000 years. Scientists have speculated that this drink contributes to the considerably low incidences of stomach cancer in certain areas of Japan. (Ho et al., 1992) The active constituent in green tea is called EGCG (epigallocatechin gallate), which has been found to inhibit carcinogenesis. Specifically, in 1992, a study reported that EGCG inhibits the "promotion stage" of chemical carcinogenesis in the liver. (Klaunig, 1992) EGCG is believed to be the constituent behind the antioxidative process of green tea, which inhibits tumors. (Ho C et al., 1992) Researchers conclude that green tea, or more specifically EGCG, is a practical cancer chemopreventive agent." (Fujiki H et al., 1992)

Coriolus versicolor, also called Karawatake, contains PSK, a protein bound polysaccharide, which possesses anti-tumor effects and prolongs the survival in metastasis models through a number of mechanisms. It primarily acts on the tumor cell, but also is an immunomodulator. PSK was found to significantly prolong the survival periods of patients with postoperative gastric and colorectal cancer and small cell carcinoma of the lungs. No side effects have been found in administration of Coriolus versicolor. Promising results have also been reported in studies on advanced colorectal cancer patients who underwent surgery and were administered three grams of PSK daily for one year as part of their therapy. The group which received the PSK survived longer and had a lower incidence of recurrence of polyps (Kobayashi H et al., 1995)

Garlic is another ancient herb, which is useful for a lot more than flavor. Allium sativum, the active constituent in garlic, has a multitude of benefits, including chemopreventive properties. In a July 1997 press release from the Mercy Cancer Institute of Pittsburgh, laboratory tests showed that garlic could help to slow the growth of tumors, inhibiting formation in the bladder and also inhibiting breast cancer. (CNN, July 21, 1997) A West Virginia University study found that oral administration of allium sativum inhibited the growth of tumors and reduced mortality in laboratory mice with bladder cancer. (Riggs DR, et al. 1997) As a preventive, garlic compounds have shown antimutagenic properties, which protect the cells from disease. (Dorant E et al., 1992) It is speculated that the allyl sulfur compounds found in garlic inhibit neoplasms and can suppress tumor cells.(Milner JA, 1996) In the Shandong Province in China, stomach cancer morality risk was 13 times lower in those that ingested 20 grams of garlic daily than those that ingested only one gram daily. (Han J, 1993)

Cancer researchers are also studying soy. Soy protein contains the isoflavones genistein and daidzein, which are found to inhibit tumor cell proliferation and in vitro Angiogenesis. Significant evidence suggests that soybeans can prevent cancer in many different organ systems. The average intake of soy protein in the Southeast Asia is considerable more than the western world. In China, 10 grams of soy are consumed daily, and in Japan, the intake is 30-50 grams daily. This is much more than the 1-3 grams daily in the western diets. These differences in soy consumption are believed to account for the significantly lower breast cancer rate in female Asian populations as compared to Americans and Europeans. Genistein is the most researched isoflavone in soy. Also, it has been found to reduce incidence, multiplicity and size of tumors. (Barnes S et al., 1995)

Chemopreventive nutrients can be one of the smartest aspects of nutrition. Vitamins, minerals, botanicals, and an overall healthy lifestyle can boost the body’s defense against cell degeneration. Such degeneration occurs not only with age, but also with exposure to some of the toxic elements, which are unavoidable in our environment. Studies and statistics show that nutrients are the key to defending the body against these elements. Through supplementation, the average diet can reach the levels of nutrients needed to battle disease.
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Clark LC, Combs GF, Turnbull BW, et al. "Effects of selenium supplementation for cancer prevention in patients with carcinoma of the skin. A randomized controlled trial. Nutritional Prevention of Cancer Study Group (see comments)." JAMA 276 (1996): 1957-63.

CNN, Pittsburg, News release July 21, 1997 "Garlic showing promise as anti-cancer agent "It can't hurt doctor says."

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