Vitamin D is good for your bones, doctors have said for years, but new research suggests that taking a vitamin pill a day might extend your life.

The findings, published in the September Journal Archives of Internal Medicine, add to the growing medical literature about the benefits of what is sometimes called the “sunshine vitamin” because it is produced by the skin in response to sunlight. Recent studies have linked vitamin D deficiencies to higher risk of cancer, diabetes and multiple sclerosis. It could play a role in reducing heart disease and preventing pre-eclampsia in pregnant women.

“It’s very new to see [the effects of] vitamin D on organs different than the bones,” said Dr. Philippe Autier, a co-author of the study. “These are very ordinary doses. You don’t need four or five pills a day.
“You should probably get rid of all the other” vitamins in the medicine cabinet, Autier said by phone from Lyon, France, where he is a researcher at the International Agency for Research on Cancer. “At this point, that’s where we are. This is quite real.”

Autier’s analysis looked at 18 trials involving vitamin D supplements that included more than 57,000 patients and evaluated doses ranging from 300 international units to 2,000 international units. Most commercially available supplements contain 400 to 600 IU. Over an average of nearly six years, those who took vitamin D had a 7 percent lower risk of death from all causes than those who did not.

Some scientists say more years of study would give better clues as to how large a role vitamin D plays in decreasing mortality. Others point out that while there was a statistically significant 7 percent drop in mortality in Autier’s analysis, because of the size of the study that only accounted for a difference of 117 people who died in the control groups as compared with those who took vitamin D supplements.

Some vitamin D researchers believe that as people have spent more and more time indoors, as opposed to the long stretches spent outdoors and uncovered in agrarian times, they have developed serious vitamin D deficiencies. They say levels that are considered normal in the United States are one-fifth of the levels of 10,000 years ago.

Dr. Cedric F. Garland, a cancer prevention specialist at the University of California, San Diego, said some cancers – rare in agrarian times – can be blamed on vitamin D deficiencies, something researchers have just begun to understand in the past few years.

“We just never realized the deficiency was there,” he said.

Garland said the link between the sunshine vitamin and cancers can be seen in new data released by the United Nations, which show cancer incidence rates in 177 countries in the world. As you move farther from the Equator, cancer levels rise, he said.

“Sunny latitudes have markedly lower incidences of cancer of the colon, breast, ovary,” he said. “It’s such a powerful association with both hemispheres. It leaves no other logical explanation.”

Getting enough vitamin D isn’t easy. About 10 minutes in the sun during peak hours – hold the sunscreen – should be more than enough to produce the currently recommended level. But many people fear the sun’s harmful rays or are stuck behind desks during the heat of the day. African-Americans might need even more exposure, as the pigmentation in their skin makes it harder to process sunlight into vitamin D and leaves them more vulnerable to deficiencies.

Fish, liver and egg yolk are the only foods that naturally contain vitamin D, though some other foods are fortified with it. Still, to get 800 IU of vitamin D from fortified milk you would have to drink two quarts a day.

“It’s impossible to get enough in your diet,” said Dr. Elizabeth Streeten, an assistant professor at the University of Maryland School of Medicine who runs the metabolic bone disease program there.

She has long been telling her patients to take 1,000 IU or more daily.
There is little evidence of vitamin D toxicity at levels under 10,000 IU a day, several said. The upper limit recommended by the National Academy of Sciences is 2,000 IU, and Garland said there might be a push to extend that to 4,000 IU. He expects to see even more good news because the research “is rapidly accelerating.”

“It seems like each month or two there’s something new that’s found,” he said.

— From the Baltimore Sun