Take Vitamin D, Live Longer?

Taking vitamin D supplements may help people live longer,
according to a new research review. But it's not yet clear exactly how vitamin
D does that.

The new review, published in the Archives of Internal Medicine, comes
at a time when vitamin D is a hot topic linked to benefits including
lower risk of some cancers and
fewer falls for elders .

The body makes vitamin D when exposed to sunshine. Vitamin D is also found
in some foods, including salmon, and in some fortified foods, including some
dairy products and cereals.

But some experts are concerned that
vitamin D deficiency is too common and suggest that the current recommended
intake of vitamin D is too low.

The new vitamin D review comes from Philippe Autier, MD, and Sara Gandini,
PhD.

Autier works for the International Agency of Research on Cancer in Lyon,
France. Gandini works for the European Institute of Oncology in Milan,
Italy.

Together, they analyzed the results of 18 vitamin D studies that included
mortality rates.

More than 57,000 adults in the U.S., U.K., and Europe participated in the
studies. Most of them were "frail" elders with low blood levels of
vitamin D, write Autier and Gandini.

Participants were typically assigned to take vitamin D supplements or a
placebo containing no vitamin D.

Their daily vitamin D doses ranged from 300 to 2,000 international units
(IU), averaging 528 IU per day, in the form of ergocalciferol (vitamin D-2) or
cholecalciferol (vitamin D-3).

Each study was designed differently, but on average, participants were
followed for 5.7 years. During that time, 4,777 participants died of any
cause.

People taking vitamin D were 7% less likely to die during the studies. The
precise reason for their lower death rate isn't clear, and the reviewers aren't
recommending a specific vitamin D dose.

An editorial published with the study recommends more research on vitamin
D's benefits.

"The roles of moderate sun exposure, food fortification with vitamin D,
and higher-dose vitamin D supplements for adults need to be debated,"
writes editorialist Edward Giovannucci, MD, ScD, who works in Harvard School of
Public Health's nutrition department

By Miranda Hitti
Reviewed by Louise Chang
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