Hold the Cheese, Halt Cancer
Testicular cancer is among the most common cancers in men between 20 and 45 years of age. A study from the University of Ottawa shows that a high intake of dairy products, particularly cheese, as well as baked goods and luncheon meats, may contribute to its development. Researchers collected data from 601 testicular cancer cases and 744 population-based controls from eight Canadian provinces between 1994 and 1997, examining nutrients, food groups, and particular foods using food-frequency questionnaires. It is suspected that female sex hormones found in dairy products could play a role.
Garner MJ, Birkett NJ, Johnson KC, Shatenstein B, Ghadirian P, Krewski D. Dietary risk factors for testicular carcinoma. Int J Cancer. 2003;106:934-41.
A second study found that calcium may play a role in cancer development, especially for prostate cancer. As part of the Cancer Prevention Study II Nutrition Cohort, researchers examined the association between calcium, dairy intake, and prostate cancer incidence, asking 65,321 male participants to complete detailed questionnaires on diet, medical history, and lifestyle. Total calcium intake (from diet and supplements) was associated with modestly increased risk of prostate cancer. High dietary calcium intake was also associated with increased risk. One potential biological mechanism is that high calcium intake down-regulates 1,25 dihydroxy vitamin D, which may increase cell proliferation in the prostate.
Rodriguez C, McCullough ML, Mondul AM, et al. Calcium, dairy products, and risk of prostate cancer in a prospective cohort of United States men. Cancer Epidemiol Biomarkers Prev. 2003;12:597-603.
Breast Cancer Again Linked to Animal Fat
Intake of animal fat, especially from red meat and high-fat dairy products, during premenopausal years is associated with an increased risk of breast cancer, according to a report in the Journal of the National Cancer Institute. Harvard researchers conducted a prospective analysis of 90,655 premenopausal women aged 26 to 46 enrolled in the Nurses’ Health Study II using food-frequency questionnaires. Because an increased risk was not associated with eating vegetable fats, researchers hypothesize that other components of meat, such as hormones or carcinogens that develop during cooking, may be to blame.
Cho E, Spiegelman D, Hunter DJ, et al. Premenopausal fat intake and risk of breast cancer. J Natl Cancer Inst. 2003;95:1079-1085.
A new study presented more evidence that hormone replacement therapy (HRT) is linked to breast cancer. The good news is that stopping HRT can bring risk back down.
More than one million British women aged 50 to 64 provided information about their use of HRT and were tracked by researchers for cancer incidence and mortality. Breast cancer risk was substantially greater for women using estrogen-progestin combination drugs, and their risk rose with each additional year of HRT usage. Researchers estimate that use of HRT over the past decade has resulted in 20,000 extra breast cancer cases in the UK, the majority associated with estrogen-progestin compounds. But five years after cessation, risk came back down.
Million Women Study Collaborators. Breast cancer and hormone-replacement therapy in the Million Women Study. Lancet. 2003; 362:419-427.
Teen Weight Tied to Ovarian Cancer
Women who were tall and heavy as youngsters appear to be at greater risk for developing ovarian cancer later in life. Researchers at the Norwegian Institute of Public Health analyzed data on more than one million women who were tracked for an average of 25 years. Girls with a body mass index in the top 15 percent of the group were 56 percent more likely to develop this type of cancer. The tallest girls in the group also had a higher risk.
Engeland A, Tretli S, Bjorge T. Height, body mass index, and ovarian cancer: a follow-up of 1.1 million Norwegian women. J Natl Cancer Inst. 2003;95:1244-1248.
Plant Compounds Combat Endometrial Cancer
Consumption of phytoestrogens (weak estrogens found in plants) was associated with a reduced risk for endometrial cancer, as reported in the Journal of the National Cancer Institute. A case-control study compared 500 women aged 35 to 79 with endometrial cancer to 470 controls, looking at intakes of three classes of phytoestrogens: isoflavones, coumestans, and lignans. Women with the highest intakes of isoflavones and lignans had a 41 and 32 percent reduced risk, respectively. The highest risk for endometrial cancer was seen in obese women consuming the least amount of plant-derived phytoestrogens.
Horn-Ross PL, John E, Canchola AJ, Stewart SL, Lee MM. Phytoestrogen intake and endometrial cancer risk. J Natl Cancer Inst. 2003;95:1158-1163.
Low-Fat Diet Boosts Immunity
Tufts University scientists have found that, when volunteers with high cholesterol levels switched to a low-fat diet, they not only lost weight, but significantly enhanced their immunity, an important factor in cancer prevention. Ten participants were initially instructed to follow a standard American-style diet deriving 35 percent of calories from fat. Then they followed three subsequent diets: one made up of 26 percent fat, one made up of 15 percent fat, and, lastly, a 15-percent fat diet with a further reduction in calories. Each diet drove cholesterol levels down, but only the last phase was associated with marked improvement in cellular immune response.
Santos MS, Lichtenstein AH, Leka LS, Goldin B, Schaefer EJ, Meydani SN. Immunological effects of low-fat diets with and without weight loss. J Am Coll Nutr. 2003;22:174-182.
Bingham SA, Day NE, Luben R, et al. Dietary fibre in food and protection against colorectal cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC): an observational study. Lancet. 2003;361:1496-1501.