Does Dairy Cause Cancer

Does Dairy Cause Cancer?

Perhaps you have heard of the China Study? Or perhaps you’ve even heard of the more recently talked-about documentary, “What the Health?” Both sources connect dairy consumption to cancer. There is so much information out there on this topic, and much can be convincing. After the release of “What the Health,” many of its viewers were moved to take on a vegan diet. Before you toss out the mozzarella stick that you packed yourself for work, let’s dive into what the literature says!

A 2017 study published in Current Developments in Nutrition looked at 1,857 women diagnosed with breast cancer between the years 2003-2014 and 1,202 control participants who had no history of cancer. The women completed a detailed food frequency questionnaire that asked about their usual intake of 110 foods and beverages the year before their cancer diagnosis. The researchers found that total dairy and yogurt intake had an inverse relationship with breast cancer. A marginally significant increased risk in breast cancer was associated with higher intakes of American cheese, cheddar, and cream cheeses. There was also a positive association between women with estrogen receptor positive breast cancer and milk consumption (McCann & Colleagues, 2017).

A 2014 review published in the The American Journal of Clinical Nutrition looked at the association between meat, dairy and cancer. There were many inconsistencies among the studies that looked at dairy’s association with bladder cancer. For instance, some studies found no relationship; others found a decreased bladder cancer risk with increased dairy intake, while others found similar findings but with insignificant estimates. There were also inconsistent findings associating prostate cancer risk and dairy consumption. An inverse association between dairy foods and colorectal cancer was observed. They stated that in general the relationship between dairy foods and cancer tends to be observed with low-fat dairy foods but not high-fat dairy foods (Abid & Colleagues, 2014)

A more recent 2015 meta-analysis of cohort studies examined the association between dairy products, calcium, and prostate cancer risk. They found an increased risk of prostate cancer with higher intakes of total dairy products, milk, cheese, low-fat milk and skim milk combined, total calcium, dietary calcium, and dairy calcium but a significant inverse association with whole milk. No association was observed between other subtypes of dairy products (skim milk, ice cream, and butter) and prostate cancer risk, but the number of studies was limited (Aune & Colleagues, 2015).

Dairy is the main source of calcium in the American diet, as well as vitamin D (since milk is often fortified in this nutrient). Both calcium and vitamin D may decrease cancer risk, but dairy also contains substances like insulin-like growth factor 1 and other growth hormones that may promote it (McCann & Colleagues, 2017). The research is vast, but seems to coincide with what our dietary guidelines already recommend and that is to choose low –fat, and fat-free milk or yogurt (Dietary Guidelines, 2016). Dairy contains many other nutrients with anti-carcinogenic potential, such as conjugated linoleic acid, butyrate, and phytochemicals, however, a diet without dairy can also provide you these nutrients. It’s important to keep in mind that other factors such as smoking, exercise, and genetics can influence cancer risk. Those which are controllable should be implemented into your daily routine to decrease your overall risk of developing chronic diseases.

References

• D. Aune, D. A Navarro Rosenblatt, D. SM Chan, A. R. Vieira, R. Vieira, D. C Greenwood, L. J Vatten, T. Norat; Dairy products, calcium, and prostate cancer risk: a systematic review and meta-analysis of cohort studies, The American Journal of Clinical Nutrition, Volume 101, Issue 1, 1 January 2015, Pages 87–117, https://doi.org/10.3945/ajcn.113.067157

• Dietary Guidelines. (2016, February 06). Retrieved April 04, 2018, from https://www.choosemyplate.gov/dietary-guidelines

• S. E. McCann, J. Hays, C. W Baumgart, E. H. Weiss, S.Yao, C. B Ambrosone; Usual Consumption of Specific Dairy Foods Is Associated with Breast Cancer in the Roswell Park Cancer Institute Data Bank and BioRepository, Current Developments in Nutrition, Volume 1, Issue 3, 1 March 2017, e000422, https://doi.org/10.3945/cdn.117.000422

• Z. Abid, A. J Cross, R. Sinha; Meat, dairy, and cancer, The American Journal of Clinical Nutrition, Volume 100, Issue suppl_1, 1 July 2014, Pages 386S–393S, https://doi.org/10.3945/ajcn.113.071597