Vitamin D supplementation directly reduces cancer risk, according to RCT
The Vitamin D Council Blog & Newsletter, February 2, 2017. Tovey, A. & Cannell, JJ.
Researchers recently presented groundbreaking findings that vitamin D reduces the risk of all cancers at the American Public Health Association’s Annual Meeting. The randomized controlled trial (RCT) was the first to evaluate the effects of vitamin D supplementation on cancer as the primary outcome. These results have arrived with much anticipation due to the consistent evidence suggesting that higher vitamin D levels and increased sun exposure are linked to lower cancer risk.
The study included 2,302 healthy menopausal women ages 55 and older. Long duration: the experiment lasted four years.
Adequate vitamin D3 dose: While the dosage did not quite meet the recommendations of the Vitamin D Council of 5000 IU per day, it provided enough vitamin D to cause a significant increase in vitamin D levels at 2,000 IU per day.
Use of a control group: Researchers compared the difference in cancer incidence between the vitamin D group and a control group. The control group received placebo.
After four years of supplementing with 2000 IU of vitamin D3 daily, the average vitamin D levels of the vitamin D group increased from 32.8 ng/ml to 43.9 ng/ml. The control group’s average levels decreased slightly from an average of 32.8 ng/ml to 31.6 ng/ml. Throughout the four years, 106 of the 2,300 women developed at least one type of non-skin cancer. The researchers discovered that cancer incidence (43 treatment and 63 controls) was significantly lower in the treatment group (p < 0.05). Furthermore, the analyses revealed that both vitamin D supplementation and vitamin D status were significant predictors of cancer risk after one year of intervention. The researchers stated, “Supplementing with 2000 IU/day of vitamin D3 and 1500 mg/day of calcium substantially reduced risk of all cancers combined. This finding provides great impetus for improving vitamin D status through advances in vitamin D nutritional policy.”