Micronutrients & recovery
Monthly high-dose vitamin D3 supplementation (200,000 IU initial bolus followed by 100,000 IU monthly) without calcium does not reduce the incidence of invasive or in situ cancer in adults aged 50-84.
Taking 100,000 IU of vitamin D3 once a month (after an initial 200,000 IU dose) does not appear to lower your risk of developing cancer. If you are taking vitamin D for cancer prevention, this specific high-dose monthly regimen is not supported by this evidence. You might discuss daily or weekly lower-dose strategies with your doctor, as this study suggests those methods warrant further investigation.
High-dose vitamin D supplementation prescribed monthly for up to 4 years without calcium may not prevent cancer.
Why this rating
Large randomized clinical trial (n=5108), double-blind, placebo-controlled, with high adherence and long follow-up (median 3.3 years).
Source
Monthly High-Dose Vitamin D Supplementation and Cancer Risk
Robert Scragg et al. · JAMA Oncology · 2018
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