Research

Hormonal

Daily supplementation with 2000 IU of Vitamin D3 reduces the incidence of advanced (metastatic or fatal) cancer in adults without prior cancer diagnosis, with the effect being statistically significant only in individuals with a normal body mass index (BMI < 25).

If you are maintaining a healthy weight (BMI < 25), taking 2000 IU of Vitamin D3 daily may help reduce your risk of developing advanced or fatal cancer. However, if you are overweight or obese, this specific dose may not provide the same protective benefit against advanced cancer, likely due to how fat stores sequester the vitamin. Consult your doctor before starting, especially if you have existing health conditions.

GoodQualifiesHIGH confidence
a significant reduction in advanced cancers (metastatic or fatal) was found for those randomized to vitamin D compared with placebo... When stratified by BMI, there was a significant reduction for the vitamin D arm in incident metastatic or fatal cancer among those with normal BMI (BMI<25: HR, 0.62 [95% CI, 0.45-0.86]) but not among those with overweight or obesity
Paulette D. Chandler et al. · JAMA Network Open · 2020

Why this rating

Randomized, double-blind, placebo-controlled trial with large sample size (N=25,871) and long follow-up (median 5.3 years), though secondary analysis.

Source

Effect of Vitamin D<sub>3</sub> Supplements on Development of Advanced Cancer

Paulette D. Chandler et al. · JAMA Network Open · 2020

DOI 10.1001/jamanetworkopen.2020.25850

rct · n=25871Cited 250×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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