More calcium, less colon cancer (Zouiouich et al. 2025)


Calcium-rich diets appear to lower colon cancer risk. Find good sources of calcium here or here (not open access).

The bad news for vegans is that vegan diets can easily be very low in calcium.

The good news for vegans is that this also seems to be true for non-dairy calcium. While it is frequently stated by scientific bodies, including by the World Cancer Reseach Fund, that dairy products lower colon cancer risk (which appears to be true), it seems that it is not dairy products per se but the calcium in dairy products ... or "non-dairy products", including calcium-containing supplements.

A study from the USA included more than 470,000 participants. This was the result:

I modified their Figure 1 by adding the numbers in red (I got these from eTable 1; they are for both sexes combined). The red numbers are mean calcium intakes (in mg/day) in the respective quintiles (i.e., five catgeories of increasing intake), except for supplemental calcium (on the very right), for which they used quartiles (i.e., four categories).
The lowest quintile/quartile is always the reference and therefore has a risk of "1". All the others are below 1, indicating a reduced risk. For example, (on the very right) a supplemental calcium intake of >999 mg/day, was associated with a hazard ratio of 0.8 (i.e., 80%, i.e., a risk reduction of 20%).
CI: confidence interval; HR: hazard ratio

This study supports the results from previous studies. The results support the idea that achieving a calcium intake of about 1000 mg/day - which is the standard recommendartion in many countries - seems to be a good idea for colon cancer prevention.

"There was a reduced risk of CRC [colorectal cancer] for every additional 300 mg/d[ay] of total (HR, 0.92; 95% CI, 0.90-0.95 [i.e., an 8% risk reduction]), dietary (HR, 0.90; 95% CI, 0.84-0.96 [i.e., a 10% risk reduction]), and supplemental (HR, 0.95; 95% CI, 0.93-0.97 [i.e., a 5% risk reduction]) calcium consumed (eTable 5 in Supplement 1)"



Reference:

Semi Zouiouich, David Wahl, Linda M Liao, Hyokyoung G Hong, Rashmi Sinha, Erikka Loftfield: Calcium Intake and Risk of Colorectal Cancer in the NIH-AARP Diet and Health Study. JAMA Netw Open, 2025 Feb 3;8(2):e2460283. doi: 10.1001/jamanetworkopen.2024.60283.