Calcium is the most abundant mineral in the body, responsible for many functions including cell signaling, hormonal secretion, muscular, vascular and nervous system firing. Studies suggest a relationship between calcium levels and colorectal, breast and ovarian cancer.

Flood et al. investigated the association of colorectal cancer and intake of calcium in over 45,000 women without history of colorectal cancer. Patients were followed over 8.5 years where 482 women developed colorectal cancer. They found roughly a 25% risk reduction of colorectal cancer with just between 400-800mg of calcium per day regardless of source (Flood, 2005).

A total of 13 studies involving over 367,000 participants it was found that dietary calcium intake reduced risk of ovarian cancer (Song, 2017). A four year trial of over 1,100 postmenopausal women found a reduced incident risk for all types of cancers with calcium and calcium plus vitamin D3 versus placebo (Lappe, 2008).

The exact mechanism of how calcium reduces the risk is unclear but it is thought to have a variety of plausible biological mechanisms including:

• Reducing proliferation of bile acids in the colon which lowers likelihood of cancer
• Formation of calcium/bile acid soaps that neutralize the bile acid’s ability to irritate the cells of colon
• May act through secondary pathways to lower proliferation rates (Flood, 2005)  

More studies need to be conducted regarding other cancers and calcium intake. Calcium is important to your body for a number of reasons so why not potentially lower cancer risk?

Flood, A., Peters, U., Chatterjee, N., Lacy, J.V., Schairer, C. & Schatzkin, A. (2005). Calcium from Diet and Supplements is Associated with Reduced Risk of Colorectal Cancer in a Prospective Cohort of Women. Cancer Epidemiology Biomarkers & Prevention. 1 (14); 126-132.

Lappe, J.M., Travers-Gustafson, D., Davies, K.M., Recker, R.R. & Heaney, R.P. (2008). Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. Am J Clin Nutr. 85(6):1586-91. doi: 10.1093/ajcn/85.6.1586

Song X, Li Z, Ji X, Zhang D. (2017). Calcium Intake and the Risk of Ovarian Cancer: A Meta-Analysis. Nutrients. 9(7):679. doi: 10.3390/nu9070679.