Should everyone over 50 take vitamin D?

It is one of the most common supplement questions in practice, and it now has a large, randomized answer.

What VITAL tested

VITAL randomized 25,871 adults in the United States, men 50 and older and women 55 and older, to vitamin D3 2,000 IU daily or placebo. They were not selected for deficiency. Median follow-up was 5.3 years.

What it found

Vitamin D did not lower the incidence of invasive cancer or major cardiovascular events compared with placebo. A later analysis of the same participants found no meaningful reduction in total, nonvertebral or hip fractures.

For most adults who are not deficient, vitamin D is not a prevention strategy for cancer, heart disease or fractures.

Secondary analyses hinted at fewer cancer deaths over time. That is worth knowing and worth studying further. It is not a reason to start supplements on its own.

What the evidence says

VITAL is large, long and well run, which makes its null results meaningful. It answers the question for a broadly healthy, mostly replete population. It does not answer it for people who start out deficient, where the case for supplementation rests on different evidence.

What to do Monday

What to do

1. Tell replete patients plainly that vitamin D did not prevent cancer, heart disease or fractures in the largest trial to date.
2. Keep testing and treating where deficiency or bone risk is likely.
3. Redirect prevention effort to what works for her: screening, exercise, and fall and bone health assessment.