EXERCISE
Exercise helps reduce the risk of:
Hormonal cancers. A study involving 25,624 women found that those who exercised at least four hours a week had nearly a 40 percent lower risk of developing breast cancer than those who were relatively sedentary. (Prostate cancer is hormonal.) Physical Activity and the Risk of Breast Cancer. New England Journal of Medicine, May 1, 1997, Vol. 336, No. 18.
Cancer in general. Exercise appears to boost the immune system or at least rid the body of free radicals. A ten-year study of over 20,000 men of all ages found that the ones who were not fit were 80% more likely to die of cancer. Reported at the annual meeting of the American College of Sports Medicine, June 2000.
Heart attacks. A study of more than 4,600 men of all ages found that regular joggers were 63 percent less likely to die over a five-year period than other non-joggers. British Medical Journal 2000;321:602-603
Impotence. If saving your life is still not enough incentive to exercise, consider a nine-year study that found that exercise appears to delay the onset of impotence by helping to keep the blood vessels clear. (About one-quarter of American men are impotent by age 65.) Urology 2000;56:302-306 (Note: The author adds that bike-riding may increase the risk of impotence.)
FOOD
Nutrition sites abound, but it is difficult to tell which you can trust. The information in this section has been documented, but it often seems that each wave of scientific research contradicts the last. Use your head.
THE BAD STUFF
Fats. Another way to gauge fat intake is to eat no more than 22 grams of any kind of fat per day. Journal of the National Cancer Institute Vol. 87, No. 9
Types of fats. Nutrition expert Dr. Artemis Simopoulos says "There are two problems with the Western diet. It is practically depleted of Omega-3 fatty acids, while at the same time is very high in Omega-6 fatty acids." Omega-6 fats are found in several oils, among them corn, safflower, cottonseed, and soybean. Corn oil, says Simopoulos, "is associated with increased number of tumors, as well as the severity of tumors." Omega-3 fats, however, are associated with lower risk. They are found in such things as walnuts and ocean fish. Although it is also found in canola oil and soybean oil, it is usually removed so that it will have a longer shelf life. Getting Your Fats Straight, CBN News, January 26, 1998
Red meats. Men who eat red meat five times a week are more than twice as likely to develop prostate cancer as men who eat red meat less than once a week. Journal of the National Cancer Institute Vol. 87, No. 9 White meats. A review of data from the Adventist Health Study, which follows the diets, lifestyles, and medical histories of over 34,000 people, showed that "the strongest risk factor [for colon cancer] among the food variables . . . was found for total meat intake." This was as true for white as for red meats. American Journal of Epidemiology 1998;148:761-774
Barbecued, smoked, and salt-cured meats. The same review found that there appear to be factors in all meats (or possibly the cooking of them or the ingredients used in curing and salting) that contribute to colon carcinogenesis. This is presumably true for prostate cancer too.
Whole-fat dairy products, such as butter, ice cream, cheese, and yogurt. Don't exceed two glasses a day of low-fat (or no-fat) milk. "High consumption of dairy products was associated with a 50 percent increased risk of prostate cancer." Cancer Causes Control 1998 Dec;9(6):541-3 Milk from cows that were treated with bovine growth hormone has been found to increase the likelihood of prostate or breast cancer. British Journal of Cancer, Vol. 76
Calcium. Men who consume 2000 mg or more of calcium a day (roughly eight glasses of milk) are more likely to develop prostate cancer and metastatic prostate cancer than men who consume one-quarter that much. Cancer Research Vol. 58 Note, however, that older men are liable to develop osteoporosis and must be sure to get enough calcium. The is doubly true for those who are taking any form of hormone-blockade therapy.
Calories. The statement in the Overview about cancers needing calories in order to grow is based on several papers, including Energy Intake and Prostate Tumor Growth, Angiogenesis, and Vascular Endothelial Growth Factor Expression, published in the Journal of the National Cancer Institute. Vol. 91, No. 6, 512-523, March 17, 1999 Other studies have shown that low-calory diets are linked to a longer lifespan (at least in rats and mice). Researchers found that "Restricting food intake to 50 to 70% of that eaten by ad lib-fed rats and mice markedly increases longevity, retards age-associated physiological deterioration, and delays and, in some cases, prevents age-associated diseases." Exp Gerontol 2000 May;35(3):299-305
Obese adults make up 22% of the U.S. population, according to a study presented at the American Obesity Association conference (September 1999).
Alcohol. Links have been found between alcohol and prostate cancer, but it is not known whether alcohol causes prostate cancer directly or indirectly. An analysis of six studies showed that women who consume two to five drinks a day have a 41 percent higher risk of breast cancer. Prostate cancer is also a hormonal cancer. Journal of the American Medical Association, 1998; 279: 535-540
THE GOOD STUFF
Fruits. Especially good for you: red grapes, strawberries, dried fruits, skins of citrus fruits, and blueberries. (This last may actually reverse part of the aging process.) Journal of the National Cancer Institute Monograph 1979;53:149-155; Blueberries: Journal of Neuroscience 1999;19:8114-8121
Fructose, found mostly in fruits, has been found to protect against prostate cancer. Eating five servings of fruit a day reduced risk by 37 percent over one serving a day. Cancer Research Vol. 58
Broccoli sprouts. Broccoli is good, but three-day-old broccoli sprouts are better. They contain 20 to 50 times the amount of chemoprotective compounds. Proceedings of the National Academy of Sciences 1997 Sep 16;94(19):10367-72
Tomatoes. Laboratory studies have shown that lycopene is a powerful antioxidant, but there is still little evidence that this occurs in the body. American Journal of Clinical Nutrition 1999;69:712-718 Nevertheless, when 72 studies on the subject were reviewed, almost half showed a link between increased tomato intake and lower cancer risk. In most cases there was a 40 percent reduction in risk, and the benefits seemed especially strong for prostate cancer. Journal of the National Cancer Institute 1999;91:317-331
Shiitake mushrooms contain a compound that is used as a supplement for cancer patients in many Japanese hospitals. The Center for Complementary and Alternative Medicine Research at UC Davis is conducting a study (announced in December 1998).
Legumes. Legumes have been linked to a decreased risk of colon cancer. They also appear to counteract the carcinogenic effects of red meat. American Journal of Epidemiology 1998;148:761-774
Grains. Whole grains are low in fat and rich in protein and fiber, but unlike their "refined" cousins, they have a short shelf life. Eat breakfast cereals, rice, pastas, and try some of the more-exotic grains, such as amaranth (AH-mah-rahn-th) or quinoa (KEEN-wah). Annals of Internal Medicine, 1993; 118: 793-803, and Environmental Health Perspectives, 1995;103 (Suppl 7):103-112.
Fiber. Most Americans only get about half of the 25 grams or more of fiber we need each day. A supplement with psyllium (the fiber used in products like Metamusil) can make up the difference. In addition to regularity, it reduces circulating androgen levels and thereby slows prostate cancer growth. Proceedings of the National Academy of Sciences, 1998;95:6791-6796
High-fiber dietSoy protein. Isoflavins appear to be the key nutrients in soy, notably genistein and daidzein. Soy products have been shown to be beneficial, especially for mice that have human prostate-cancer cells. Cancer Rates and Risks, Harras A., editor, 1996 Harvard Medical School study, announced at the Federation of American Societies for Experimental Biologies, May 1999
Information about soy productsTea. A powerful antioxidant ingredient in green tea, epigallocatechin-3-gallate (EGCG), has killed human cancer cells in lab experiments. Journal of the National Cancer Institute (1997;89(24):1881-1886) The same ingredient has been shown to inhibit urokinase, an enzyme needed for cancer growth. Nature. 1997 Jun 5;387(6633):561 Green tea contains between 100 and 200 milligrams of EGCG. Four cups per day is recommended.
About tea About green teaVITAMINS
Vitamin E. One study showed a strong link between Vitamin E and lower prostate (and other) cancer rates, even though the supplement was only 50 IU per day. Journal of the National Cancer Institute 1998 Mar 18;90(6):440-6. Unfortunately, information in several recent studies suggests that most Vitamin E supplements may not be very effective—and may even have a negative effect on your health.
Vitamin E is composed of four tocopherols: alpha, beta, delta, and gamma. Of these, the most useful may be the gamma, because it rids the body of at least two dangerous substances. However, nearly all vitamin E supplements include only alpha-tocopherols. And labels that say the pills contain naturally occurring beta-, gamma-, and delta-tocopherols may simply be referring to those present in the vegetable oil that is used as a base.
The information about gamma-tocopherols appeared in a study by biochemist Stephan Christen of the University of California, Berkeley. It also showed that high levels of alpha-tocopherol reduce the levels of the gamma type in the blood, so that a large dose of Vitamin E may prove counter-effective. According to Christen, pills with a mixture of alpha and gamma would not be expensive to make. Both are readily extracted from such plants as soybeans. Proceedings of the National Academy of Sciences, 1 April 1997
The report drew criticism from some researchers and support from others, so, until the scientific community settles the alpha/gamma dispute, you should try to get your Vitamin E from such things as milk, eggs, cereal, fish, corn, soybeans, nuts, and grains. (Beware: the last three are high in fat.) If you do buy E supplements, make sure that the name of the tocopherol is preceded only by the letter d, which indicates that it is the natural form. (The synthetic is indicated by the letters dl. For example: dl-alpha-tocopherol.)
A recent survey by the Centers for Disease Control and Prevention found that almost 30 percent of US adults have low blood levels of vitamin E. African-Americans tend to have especially low levels. American Journal of Epidemiology 1999;150:290-300.
About vitamin E
MINERALS
Selenium. This is an essential trace mineral found in grains, fish, and garlic. According to Dr. Meyers, however, foods grown in at least one section of the US—the eastern seaboard from Pennsylvania to Florida—are reported to be seriously deficient in this mineral.
One study reported that men taking a supplement of 200 mcg of selenium daily showed "a significant (63 percent) reduction in the secondary endpoint of prostate cancer incidence during 1983-93." Journal of Urology, 1998, May;81(5):730-734 Another report supports these findings. British Journal of Urology 1998 May;81(5):730-4 However, studies of selenium toxicity suggest that taking more than 800 mcg a day is dangerous. American Journal of Clinical Nutrition 37: 872-881, 1983
Selenium, National Institute of Health
About vitamins, minerals, trace elements and diet modification
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