We have seen short term studies in the past suggesting that higher intake of calcium reduces the risk of colorectal cancer. In 2025, with over 20 years of follow-up on almost 500,000 participants (average age 62 and 59.5 years for women and men, respectively) the study showed a strong and consistent correlation with higher intake of calcium from food and supplements and a reduction in colon and rectal cancers. Remember that colorectal cancer is the second most common cause of cancer death, so these findings are very important.

More specifically the study showed that participants in the highest 20% of calcium intake (over the 20 plus year period) had 29% reduction in colorectal cancer, compared to those who were in the lowest 20% of calcium intake. They showed that for every 300 mg of total calcium total calcium intake, dietary calcium intake, and calcium supplement intake colorectal cancer risk was reduced by 8%, 10%, and 5%, respectively. Male participants with the highest calcium intake (the top 20% intake level) were consuming 2056 mg calcium per day and for women, 1773 mg calcium per day. This level of intake was associated with a 29% reduced risk of developing colorectal cancer, This is really impressive.

How does calcium reduce risk of colorectal cancer?

The evidence is very strong that calcium directly and indirectly slows the rate of cell replication in cells that line the colon and rectum. Slowing down the rate of cell replication reduces the risk of genetic mutations developing that lead to cancer development. It appears to be that simple. The bottom line, in my view, is to ensure that you are consuming at least 1500 mg of calcium per day, which also helps to prevent osteoporosis.

This can be done through a combination of consuming healthy foods high in calcium, such as low-fat yogurt, whey protein shakes, along with taking a multi-vitamin each day that provides 500 mg of calcium and 1,000 IU of vitamin D (as vitamin D works with calcium to prevent osteoporosis and colon cancer). These are practical and simple ways to get appreciable amounts of calcium and vitamin D on a daily basis.

I have provided a link to the research in the text below.

References:

Brooks M. Higher calcium intake may lower CRC risk. Medscape. (February 24, 2025) Higher Calcium Intake May Lower CRC Risk

Zoulouich S et al. Calcium intake and risk of colorectal cancer in the NIH AARP Diet and Health Study. JAMA Netw Open,2025;8(2): Calcium Intake and Risk of Colorectal Cancer in the NIH-AARP Diet and Health Study | Public Health | JAMA Network Open | JAMA Network

Eat Smart, Live Well, Look Great,
Dr. Meschino