More studies are indicating that vitamin D is a "hot" nutrient — and not just because it is called the "sunshine" vitamin.

A recent paper in the Archives of Internal Medicine concluded that vitamin D intake is associated with lower death rates from a variety of causes. The authors were intrigued by the observation that death from many diseases, including cancer, heart disease and diabetes, appears to increase with increasing latitude. People who live farther from the equator seem to have higher death rates.

CHRIS ROSENBLOOM FIT TO EAT Have a question of general interest? E-mail Rosenbloom Related: • More on food and drink • Restaurant reviews and search More Rosenbloom You can work '101 Foods' into your diet  Know your nutrition: A quick quiz for fall  Three to be careful with in healthy diet  Grapefruit, cancer link considered preliminary  Beta carotene powers orange fruits, veggies  Our levels of the 'sunshine' vitamin decrease as we age  'Repair' muscles after long-distance running  Food-drug interaction an important issue  • Chris Rosenbloom, Ph.D., R.D., is a member of the nutrition faculty in the College of Health and Human Sciences at Georgia State University.

The farther from the equator, the less we are exposed to ultraviolet light. Light from the sun converts a chemical in our skin into vitamin D, and further conversions in the liver and kidney make the most active form of the vitamin: vitamin D3.

The role of vitamin D in chronic disease is unclear, but the vitamin is needed for strong bones and to regulate cell growth. A lack of the vitamin might affect the growth of cancer cells and the growth of artery-clogging plaque that leads to heart attack and stroke.

It has long been known that blood levels of vitamin D decrease as we age (by age 70, we make about half of what we did at age 20). Adults should get a blood test to make sure they are getting enough vitamin D.

If we make less as we age and if slathering on sunblock reduces our ability to make the vitamin, where can we get it?

Very few foods naturally contain vitamin D. It is a fat-soluble vitamin found in fatty fish, like salmon, as well as liver and eggs. Milk is not a natural source of the vitamin, but most dairies fortify milk with it. Even breast milk is vitamin-D deficient, so breast-fed infants need vitamin D supplements. One cup of most commercially available milk contains 100 International Units of vitamin D or about 25 percent of daily needs for young adults. You might be surprised that another popular dairy food, yogurt, may not contain any vitamin D. For example, Yoplait yogurt has 80 IU of vitamin D in a 6-ounce container, but Dannon fruit-on-the-bottom yogurt has none.

Vitamin D content does not always show up on the nutrition facts panel, so be a label reader to find out if your favorite food contains this important vitamin. Calcium-fortified orange juice often contains vitamin D (Tropicana with calcium and vitamin D provides as much calcium and vitamin D in 8 ounces as in one glass of milk), but Tropicana regular orange juice doesn't contain the vitamin.

Most multivitamin supplements contain 400 IU of vitamin D. So if you don't drink milk or get enough from your favorite foods, consider taking a daily multivitamin. The Institute of Medicine has set 2,000 IU as an upper limit, so don't take more than this in supplement form.