Vitamin D and longevity

Seven's On Call with Dr. Jay Adlersberg
November 13, 2007 9:00:00 PM PST
A lot of people feel like they get the winter blues. Part of that is because there's less sun.Seven's On Call with Dr. Jay Adlersberg.

Shorter days mean less exposure to the sun. We generally warn about over-exposure and the risk of skin cancer, but under-exposure? An article in the American Journal of Clinical Nutrition says not getting enough sun may reduce your body's Vitamin D. So what? Good levels may mean a longer life.

Vitamin D comes from the sun. Sunlight stimulates the skin to make the vitamin. But with fall here, the sun is up less and less. That's not good for any of us, especially with the study showing that Vitamin D is linked to longevity.

"There are diseases like osteo-arthritis and autoimmune diseases that are associated with Vitamin D deficiency," Dr. Wahida Karmally said.

The study looked not at deficiency, but at more than 2,000 women with all sorts of Vitamin D blood levels.

Researchers measured genetic factors linked to longevity. Those with the highest Vitamin D levels had improvement in these factors that are equivalent to five extra years of life.

During winter in the northeast, even when there's not a cloud in the sky, there's not enough sunlight to make adequate amounts of Vitamin D.

So look for salmon, mackerel and tuna, which are all rich in Vitamin D. Milk products and cereals are fortified with Vitamin D. A small amount of skim milk has 25 percent of the 400 unit recommended daily dose.

Certain cereals have what you need. Combine it with a glass of skim milk, and you are going to get about a third of what you need.

Older adults and teens don't get enough D. That's often because unfortified juices and sodas make up most of what many people drink.

Increasing intake of foods with Vitamin D makes sense. By the way, soy milk is not fortified. And multi-vitamins provide a full daily dose.

Older people make less of the vitamin in the skin, so they especially should look to foods for more. The minimum requirement, depending on age, is about 200 units. Nursing mothers, take note: Breast milk alone does not supply enough Vitamin D.