Vitamin D did not change how many people died
Nearly 26,000 US adults on 2,000 international units daily for five years had the same rates of cancer, heart attack, stroke and death as placebo. So did 21,000 Australians.
What the study found
Two trials of 47,000 people found no change in death rates
Nearly 26,000 US adults on 2,000 international units of vitamin D3 daily for five years had the same rates of cancer, heart attack, stroke and death as those on placebo. Over 21,000 older Australians on 60,000 international units monthly for five years had the same death rate too.
The caveat · Most had enough vitamin D already
Neither trial screened people in for low vitamin D, so both test adding more to people who mostly had enough rather than correcting a shortfall. The Australian participants averaged 77 nanomoles per litre before they started, in a country with a great deal of sun. Five years may be short for cancers that take longer than that to surface.