Vitamin D3

Featured study

Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease ↗
The New England journal of medicine · 2019 · PMID 30415629

Who was studied

25,871 U.S. men aged 50 and older and women aged 55 and older, including 5,106 Black participants, followed for a median of 5.3 years.

How

Nationwide randomized, placebo-controlled trial with a two-by-two factorial design (vitamin D3 and omega-3 tested together and separately).

What it found

Vitamin D did not reduce invasive cancer (hazard ratio 0.96) or major cardiovascular events (0.97) compared with placebo. Secondary outcomes, including cancer deaths and specific cancers, also showed no clear benefit, and no excess risk of high calcium was found.

Limits

Most participants were not vitamin D deficient at the start, so the trial cannot rule out benefits for people with low levels. It tested prevention in a general population, not bone health or treatment of deficiency.

Safety & what remains unknown

Very high intake over time can raise blood calcium. People with kidney stones, certain granulomatous diseases or who take some heart or diuretic medicines should ask a clinician first.

Talk to a clinician before starting a supplement, especially if you are pregnant, take prescription medicines or have a medical condition.

Where to find it

Search results and listings are not quality-checked or endorsed by PepsRadar. Look for third-party testing (for example USP or NSF marks) and check with a clinician about interactions.