Study suggests lack of "sunshine vitamin" dims health outlook

The old song says, "sunshine on my shoulders makes me happy." But perhaps it should add: "and keeps me healthy." More research is showing that vitamin D, which the skin produces when exposed to sunlight, may do more for the body than experts previously thought. And, according to a new study, a lack of it may be linked to a higher chance of dying early from heart problems and other causes.

We've known for a long time that vitamin D helps our bodies absorb calcium, which our bones need to grow and stay strong. You can get vitamin D from foods and supplements, but the best source is your skin (hence the nickname "the sunshine vitamin").

In the new study, researchers tracked levels of vitamin D in more than 3,200 men and women for nearly eight years. All the people in the study were white and older (the average age was 62) and they'd had symptoms suggesting heart problems. At the end of the study, researchers found that those with low levels of vitamin D were more likely to have died, either from heart and circulation problems or other causes. In fact, 37 percent of the group with the lowest amount of one form of vitamin D had died, compared with 13 percent of the group with the highest amount. These are striking numbers, to be sure, but researchers caution that they can't be certain a lack of vitamin D contributed to their death. The study only shows that there might have been a link.

Although the study is far from conclusive, it does add to growing evidence that the risks of low vitamin D go far beyond our bones. Studies have also found that a lack of vitamin D may increase the problems with the immune system, certain cancers, type 1 and type 2 diabetes, multiple sclerosis, and problems with the heart and circulation.

And, unfortunately, many of us aren't getting enough of this vitamin, experts say. Up to 6 in 10 older people in North America and worldwide don't have enough of this nutrient. Studies show many younger people also have low amounts, which can lead to malformed bones in children.

Experts aren't sure why vitamin D levels are low, but possible reasons include air pollution, which blocks some sunlight (this is called global dimming), and less time spent outdoors.

What you need to know. It's hard to know how much vitamin D you're getting, as much of it may come from time spent in the sun. But many experts say as little as 10 minutes outdoors three or four times a week provides most people with what they need. Those who are older than age 60, have darker skin, are very overweight, or live in northern areas (where the sunlight is less intense) need more.

Complicating matters, sunscreen blocks out rays that help the skin make this vitamin, even though wearing sunscreen is important to protect against skin cancer. Staying in the sun for a short while without sunscreen is likely to be safe, but it can be difficult to get the balance right.

If your time outdoors is limited, make sure you get vitamin D from what you eat and drink. Vitamin D is plentiful in halibut, salmon, and other fish. Also milk, orange juice, and cereals often have this vitamin added. You can also take supplements.

Talk to your doctor if you have questions about vitamin D and whether you're getting enough. And, now that summer is here, why not follow John Denver’s advice?

—Sophie Ramsey, patient editor, BMJ Group

ConsumerReportsHealth.org has partnered with The BMJ Group to monitor the latest medical research and assess the evidence to help you decide which news you should use.

Read more on safe supplements (free) and check out our Natural Medicine Ratings (subscribers only) on vitamin D.

Comments

[Nancy Sutter Axford]

Halibut are over-fished as are most salmon. Please include sardines among your suggestions for fish. They are lower on the food chain and much more common.