Cancer

For the latest studies on dairy cheese and cancer, see here.

Ovarian Cancer

Research links cow’s milk to increased risk of ovarian cancer. In a study examining the incidence rates of ovarian cancer in 40 countries across 5 continents, researchers found they were most closely correlated with cow’s milk intake (1). The researchers suggest that women who drank just 1 or more glasses of whole cow’s milk per day were at three times greater risk for ovarian cancer (1). Skim milk has also been tied to this deadly disease.

Our tip to you: Eat more vegetables! Although dairy consumption can increase the risk of developing ovarian cancer, vegetables can reduce it (2). Eating 3 or more servings of vegetables per day can decrease ovarian cancer risk by 39% (3).

References

Ganmaa D, Sato A. The possible role of female sex hormones in milk from pregnant cows in the development of breast, ovarian and corpus uteri cancers. Med Hypotheses 2005; 65(6):1028-37.
Susanna C Larsson, Leif Bergkvist, Alicja Wolk. Milk and lactose intakes and ovarian cancer risk in the Swedish Mammography Cohort. The American Journal of Clinical Nutrition 2004; 80(5):1353-1357.
Larsson SC, Holmberg L, Wolk A. Fruit and vegetable consumption in relation to ovarian cancer incidence: the Swedish Mammography Cohort. Br J Cancer 2004; 90(11):2167–2170.

Prostate Cancer

Research links cow’s milk to increased risk of prostate cancer. According to the American Cancer Society, American men have a 1 in 9 chance of developing prostate cancer—the second most common to skin cancer. Drinking cow’s milk each day can increase a boy’s risk of advanced prostate cancer threefold! (2) The same can be said for adults. A study of men across 42 countries revealed that cow’s milk was more closely linked to the development of prostate cancer than any other food (3). In fact, a primary research study found a 60% higher relative risk for those men consuming 2 cow’s milk servings per day compared to zero servings per day (4). Why might this be? Some researchers suggest it may be in part due to the high dietary phosphate content of cow’s milk (5), while others suggest that cow’s milk proteins can activate an enzyme whose signaling pathway can initiate prostate cancer development (6).

Our tip to you: Research shows that men who stopped consuming dairy and opted for a plant-based diet were able to cut their risk of prostate cancer by 35% (7). We suggest avoiding dairy to lower your risk.

References

American Cancer Society: Key Statistics for Prostate Cancer.
Torfadottir JE, Steingrimsdottir L, Mucci L, et al. Milk intake in early life and risk of advanced prostate cancer. Am J Epidemiol. 2012; 175(2):144–153.
Ganmaa, D. , Li, X. , Wang, J. , Qin, L. , Wang, P. and Sato, A. Incidence and mortality of testicular and prostatic cancers in relation to world dietary practices. Int. J. Cancer 2002; 98:262-267.
Edward Giovannucci et al. Calcium and Fructose Intake in Relation to Risk of Prostate Cancer. Cancer Res. 1998; 58(3):442-447.
Newmark HL, Heaney RP. Dairy products and prostate cancer risk. Nutr Cancer. 2010; 62(3):297-9.
Melnik BC, John SM, Carrera-Bastos P, Cordain L. The impact of cow’s milk-mediated mTORC1-signaling in the initiation and progression of prostate cancer. Nutr Metab (Lond). 2012; 9(1):74.
Tantamango-Bartley Y, Knutsen SF, Knutsen R, et al. Are strict vegetarians protected against prostate cancer? Am J Clin Nutr. 2016; 103(1):153–160.

Breast Cancer

Research links cow’s milk to increased risk of breast cancer. A study of breast cancer cases that surveyed 40 countries across five continents revealed that cow’s milk was the second food most correlated with breast cancer (the first was meat) (1). Researchers suggest that since the cow’s milk we consume today is produced from pregnant cows, in which estrogen and progesterone levels are elevated, this can have adverse effects on the body and potentially stimulate the development of breast cancer (1).

Additionally, research has shown that cows’ milk increases our circulating levels of insulin-like growth factor (IGF-1), a growth-stimulating hormone, which can lead to unregulated cell growth, a characteristic of cancer (2). IGF-1 has also been shown to play a role in increasing other known risk factors for breast cancer, such as greater adult height, number of menstrual cycles, and higher birth weight (3).

Our tip to you: Don’t be afraid to consume soy! Circulating estrogen levels decreased by 50% in women who drank soy milk every day and stayed down for one month even after they stopped drinking it (4). Soybeans contain phytoestrogens which not only can act as estrogen blockers (5), but also inhibit breast cancer cells from producing estrogen in the first place (6).