How is calcium and vitamin D supplementation used to prevent colon cancer?

Updated: Apr 15, 2020
  • Author: Tomislav Dragovich, MD, PhD; Chief Editor: N Joseph Espat, MD, MS, FACS  more...
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Although earlier data had strongly indicated that calcium supplementation can help prevent colorectal cancer, and had suggested a preventive effect of vitamin D supplementation, a randomized trial by Baron et al found that daily supplementation with vitamin D3 (1000 IU), calcium (1200 mg), or both after removal of colorectal adenomas did not significantly reduce the risk of recurrent colorectal adenomas over a period of 3 to 5 years. [141]

However, a randomized trial by Barry et al suggested that vitamin D receptor genotype may affect the benefits of vitamin D3 supplementation. In their analysis of 41 single-nucleotide polymorphisms (SNPs) in vitamin D and calcium pathway genes in 1702 patients with colorectal adenomas, vitamin D3 supplementation decreased risk for advanced adenomas (but not adenomas overall) by 64% in study subjects with the AA genotype at the rs7968585 SNP, but increased risk by 41% in those with one or two G alleles. The benefits of calcium supplementation were not significantly linked to genotype. [142]

Circulating levels of 25 hydroxyvitamin D (25[OH]D) that are optimal for preventing colorectal cancer may be significantly higher than levels necessary for bone health, according to an international collaborative meta-analysis that pooled 17 cohorts. Although levels of 50 to < 62.5 nmol/L are considered adequate for bone health by the Institute of Medicine, the study found that levels of 75–< 87.5 were associated with 19% lower risk and levels of 87.5–< 100 nmol/L were associated with 27% lower risk. [143, 144]

For each 25 nmol/L increment in circulating 25(OH)D, colorectal cancer risk was 19% lower in women and 7% lower in men. In addition, the study confirmed that vitamin D deficiency increases colorectal cancer risk: 25(OH)D levels of less than 30 nmol/L were associated with a 31% greater risk compared with adequate levels. [143, 144]

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