By Jennifer Reilly, R.D., and Neal D. Barnard, M.D.
Does Childhood Dairy Intake Increase Later Cancer Risk?
Children who consume a high-dairy diet—equivalent to nearly 2 cups of milk per day—have almost three times the risk of developing colorectal cancer in adulthood compared with children who consume less than half a cup of milk per day, according to a new study in the American Journal of Clinical Nutrition. These findings held true after researchers adjusted for differences in meat, fruit, and vegetable intake, as well as socioeconomic status.
Van der Pols JC, Bain C, Gunnell D, Smith GD, Frobisher C, Martin RM. Childhood dairy intake and adult cancer risk: 65-y follow-up of the Boyd Orr cohort. Am J Clin Nutr. 2007;86:1722-1729.
Meat Consumption Increases Breast Cancer Risk
The more meat a woman eats, the greater her risk of breast cancer, according to a new study of postmenopausal Danish women. The study looked at 378 women who developed breast cancer and matched them to control subjects who did not develop breast cancer. A higher intake of meat—including poultry and fish, as well as red meat and processed meat—was associated with a significantly higher breast cancer incidence rate. Every 25 gram increase in consumption of total meat, red meat, and processed meat led to a 9, 15, and 23 percent increase in risk of breast cancer, respectively. However, the degree of risk may depend on genetics. Certain genes activate the carcinogens (heterocyclic amines) found in cooked meat. The study showed that women with genes that rapidly activate these carcinogens are at particular risk of breast cancer if they eat meat.
Egeberg R, Olsen A, Autrup H, et al. Meat consumption, N-acetyl transferase 1 and 2 polymorphism and risk of breast cancer in Danish postmenopausal women. Eur J Canc Prev. 2008;17:39-47.
More Studies Link Milk to Prostate Cancer
Men who consume low-fat and nonfat milk face an increased risk of prostate cancer, according to two new studies in the American Journal of Epidemiology.
One study included 82,483 men in the Multiethnic Cohort Study, 4,404 of whom developed prostate cancer over an average follow-up of eight years. Researchers found no association between prostate cancer risk and calcium and vitamin D intake, whether in the form of food or supplements. However, the study did find a positive association between consuming 1 cup or more per day of low-fat or nonfat milk and developing prostate cancer.
The other study included 293,888 participants in the National Institutes of Health (NIH)-AARP Diet and Health Study. Consuming two or more daily servings of skim milk was associated with an increased risk of advanced prostate cancer.
Several previous studies—including two large Harvard studies—have shown that milk-drinking men have a significantly higher risk of prostate cancer. Researchers offer two possible reasons for the association: Milk drinking increases blood levels of insulin-like growth factor, which is associated with cancer risk. It also decreases activation of vitamin D precursors. Vitamin D helps protect the prostate against cancer.
Park S, Murphy SP, Wilkens LR, et al. Calcium, vitamin D, and dairy product intake and prostate cancer risk: the Multiethnic Cohort Study. Am J Epidemiol. 2007;166:1259-1269.
Park Y, Mitrou PN, Kipnis V, et al. Calcium, dairy foods, and risk of incident and fatal prostate cancer: the NIH-AARP Diet and Health Study. Am J Epidemiol. 2007;166:1270-1279.
The Cancer Project is a nonprofit PCRM subsidiary that advances cancer prevention and survival through nutrition education and research.