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Vitamin D deficiency prevalent

March 19, 2006 12:50 am

JUST AS PLANTS SOAK UP sunlight and transform it into life-giving food, our skin can transform sunshine into vitamin D. But in American cities, most people don't get enough sun to make enough vitamin D.

Dermatologists warn us to avoid the sun for fear of skin cancer. It's also hard to get enough vitamin D from foods.

Scientists warn that two-thirds of older Americans--and many younger adults and children--just don't get enough of this vital nutrient.

Vitamin D protects the bones and may reduce the risk of diabetes and cancers of the colon, breast, prostate and ovaries. It also may reduce certain types of back and muscle pain.

Even if people got as much Vitamin D as is currently recommended, it might not be enough. Some experts argue the recommendations should be at least double what they are now.

The recommended amounts vary by age, but some experts say people of all ages should get at least 800 units day. That's the equivalent of about 8 glasses of milk.

If you spend your winters here in the U.S., you are not getting enough sun to make sufficient vitamin D. And if you have a darker complexion, you're even more at risk and need to get vitamin D from food or supplements.

A national survey of more than 16,000 American showed that 95 percent of people over 50 do not get enough vitamin D from food alone.

Older Americans who take vitamins do better, but still only 65 percent of white, 83 percent of Hispanic and 90 percent of black seniors meet the current recommendations.

Older people are especially at risk of suffering from Vitamin D deficiencies. As people age, they need more vitamin D to keep from developing osteoporosis, or brittle bones.

Hispanic and African-Americans have higher needs, as do some people with liver and kidney disease. So do people with digestive problems such as pancreatitis, celiac disease, and intestinal surgeries.

People taking glucocorticoid medications for allergies and lung disease may have higher needs as well. And for children, the American Academy of Pediatrics recommends supplements for breastfed babies and any child who drinks less than 2 cups of milk or formula daily.

Your body is constantly, silently remodeling your bones, and vitamin D is critical. You can eat huge amounts of calcium, but unless you get enough vitamin D, your body won't use the calcium.

Getting 700 to 800 International Units of vitamin D per day is enough to reduce the risk of broken bones. It also can reduce by nearly half the risk of elderly people falling, according to researchers at Harvard University and other institutions.

That's a big deal, because for older people with fragile bones, one bad fall can cause a broken hip and leave them unable to walk, drive or care for themselves for months or years.

Pain is a hallmark of vitamin D deficiency. While mild vitamin D deficiency has no symptoms, in more dramatic cases, the pain can be disabling.

The pain is felt in the bones, not the joints, and often begins in the lower back, spreading to the hips, upper legs and ribs. Some people also experience muscle weakness. In the long-term, people with vitamin D deficiency develop weakened bones.

Often, people with short-term vitamin D deficiency are misdiagnosed with somatization disorder (psychological pain that causes physical pain), or with fibromyalgia, a mysterious pain syndrome.

Yet in one study, two-thirds of patients who had been diagnosed with somatization disorder felt better when they received daily supplements of 800 units of vitamin D, with 1,000 milligrams of calcium. Within 2 to 7 months, they were pain-free. In a smaller study, patients with fibromyalgia also improved after taking vitamin D.

A doctor can order a blood test for vitamin D deficiency called 25-hydroxy-vitamin D.

Recently, a study made headlines stating that vitamin D and calcium don't reduce cancer risk in middle-aged women. But the women in the study were taking only 400 units of vitamin D.

Experts say the amount needed to prevent colon cancer seems to closer to 800 or 1,000 units, based on other studies.

Other studies show that people with higher levels of vitamin D in their blood have lower rates of prostate, breast and ovarian cancers.

For diabetes prevention, the Nurses Health Study shows that women who get more than 1,200 milligrams of calcium and 800 units of vitamin D per day cut their risk of developing diabetes by one-third, compared with women who get 600 milligrams of calcium and 400 units of vitamin D.

In the summer, fair-skinned people can get enough vitamin D from 20 minutes in the sun two or three times weekly. Darker-skinned folks need more time.

But the American Academy of Dermatology recommends avoiding the sun and instead urges getting vitamin D from foods or supplements.

As always, I think it's more fun to eat food than pop pills. But when it comes to vitamin D, we don't have a lot of choices.

In the U.S., regular milk, lactose-reduced milk and soy milk are fortified with vitamin D, although most cheeses and yogurts are not. Fatty fishes such as salmon, herring, and mackerel are rich in vitamin D, as are oysters and even shrimp.

Not many vegetarian foods supply vitamin D, except for shiitake mushrooms, so vegetarians need to be vigilant about taking vitamin D supplements.

Some cereals and juices are being fortified with vitamin D, so read labels.

If you're not up to eating three servings daily of the foods above, consider supplements. Our government recommends that infants to 50-year-olds get 200 International Units per day. If you're 51 to 70, Uncle Sam recommends 400 units, and those older than 70 should try for 600 units, which is very difficult to get from food alone.

Some experts are recommending a minimum of 800 to 1,000 units for all ages, but at this point I would not recommend going beyond 1,000 units without a doctor's supervision.

Too much vitamin D from supplements may cause kidney stones, nausea, vomiting, weakness, confusion and heart problems. If you have liver or kidney disease, vitamin D supplementation may be helpful, but talk with your doctor before taking supplements.

JENNIFER MOTL, a registered dietitian, welcomes reader questions via her Web site, brighteating.com, or mailed to Nutrition, The Free Lance-Star, 616 Amelia St., Fredericksburg, Va. 22401.