Lacking in vitamin D? It's time to see the light

Arthritis. Obesity. Diabetes. Heart disease. Depression. Cancer.

Vitamin D could help prevent all these and more, some experts say. And it's free. Most people can get it just by spending a little more time in the sun.

Known as the sunshine vitamin, it's long been known that vitamin D can help build strong bones and teeth. But in recent years, vitamin D deficiency has been linked to a growing number of health concerns.

"The benefits of vitamin D are varied and profound," says Michael F. Holick, a leading vitamin D expert and author of "The Vitamin D Solution: A 3-step Strategy to Cure Our Most Common Health Problems" (Hudson Street Press, $25.95).

"(Vitamin D) may be as vital to your heart and brain health as it is to bone health," Holick says. "Increasing levels of vitamin D can treat, prevent, and even reverse a remarkable number of daily ailments."

Are you getting enough vitamin D?

The National Osteoporosis Foundation recommends 400 to 800 IU (international units) of vitamin D daily for adults under 50, and 800 to 1,000 IU for adults 50 and older. But many experts say most people need more — up to 2,000 IU a day — to raise our levels high enough to fight disease.

How do you know where you stand? First, talk to your doctor about a "serum 25-hydroxyvitamin D" test, the only test that accurately measures blood levels for vitamin D.

If you need more vitamin D, here are a few ways to get it.

Eat naturally D-rich foods that include oily, wild-caught fish such as salmon, Atlantic mackerel, sardines, shrimp and tuna a few times a week. Cod liver oil and Shitake mushrooms are also a good source of vitamin D.

Go for fortified vitamin D beverages and foods, including milk and soy milk, orange juice and other fruit juices, butter substitutes, some cereals, yogurt, egg yolks and liver.

Take a supplement. Add a calcium and vitamin D supplement containing at least 400 IU of D daily. (Don't overdo it, though. Very high amounts of vitamin D can be harmful and may result in kidney stones and other kidney problems. Some kidney problems can cause bone loss.)

If you are not at risk of skin cancer, enjoy a little sun. You don't have to burn or overexpose your skin. Experts say about 15 minutes — before sunscreen — is usually enough. Use sunscreen after this initial sun exposure.

Source: National Osteoporosis Foundation and "The Vitamin D Solution"

Take this quiz to see if you're getting enough vitamin D.

How many of these statements apply to you?

I rarely go out in the sun.

I wear sun block and cover up my skin when I go out in the sun, especially during the summer months or when I'm outside in the middle of the day.

My wardrobe typically covers most of my skin, including my arms and legs.

I do not take a multivitamin along with a vitamin D supplement every day.

I do not take a separate vitamin D supplement every day.

I do not eat wild, oily fish (salmon, mackerel, herring, sardines, etc.) two to three days a week.

I do not eat a lot of mushrooms.

I drink fewer than 10 glasses of fortified milk or orange juice a day.

I am naturally dark skinned or am of African or Hispanic descent.

I am older than 60.

I am younger than 20.

I am overweight and carry a considerable amount of extra fat.

When I press firmly on my sternum (breastbone) with my thumb or forefinger, it hurts.

When I press firmly on my shins, I feel pain.

I feel like I have less energy and muscle strength than I should.

I take anti-seizure or AIDS medication.

I take glucocorticoids (e.g., prednisone).

I have celiac disease.

I have intestinal disease.

I have had gastric bypass surgery.

If you agree with any of the above statements— yes, any — there's a good chance you suffer from vitamin D deficiency. But the only sure way to know is to ask for a 25-hydroxyvitamin D test, also called a 25 (OH) D test.

Source: The Vitamin D Solution

Vitamin D fast facts

Recent studies are hailing vitamin D as a "super" vitamin. Here's what you need to know:

Unlike other vitamins, vitamin D is actually a hormone. It is produced by your skin in response to exposure to ultraviolet radiation from natural sunlight.

The healing rays of natural sunlight cannot penetrate glass. So you don't generate vitamin D when sitting in your car, home or office.

It is nearly impossible to get adequate amounts of vitamin D from your diet. Sunlight exposure is the only reliable way to generate vitamin D in your own body.

A person would have to drink 10 tall glasses of vitamin D fortified milk each day just to get minimum levels of vitamin D into her diet.

The farther you live from the equator, the more sun exposure you need to generate vitamin D. Canada, the United Kingdom and most U.S. states are far from the equator.

People with dark skin pigmentation may need 20 to 30 times as much exposure to sunlight as fair-skinned people to generate the same amount of vitamin D.

Even weak sunscreens (like SPF 8) can block your body's ability to generate vitamin D by 95 percent.

It is impossible to generate too much vitamin D in your body from sunlight exposure; your body will self-regulate and only generate what it needs.

Source: "The Vitamin D Solution"

And a 2007 study in the American Journal of Clinical Nutrition concluded that post-menopausal women who improved their calcium and vitamin D levels substantially reduced all cancer risk.

"Vitamin D is the most common nutritional deficiency in the world, but its effects manifest in so many other conditions that people often focus on treating the symptoms instead of looking deeper in the cause," Holick says.

Most people don't get nearly enough D, which is produced through the skin by exposure to sunlight. With more people spending less time outdoors — and using sunscreen when they are outside — vitamin D deficiency is on the rise.

Three out of four Americans are deficient in vitamin D, up from one out of two 20 years ago, Holick says. About 40 percent to 60 percent of black adults are vitamin D deficient, he says.

In the black community, some experts are calling vitamin D deficiency a "hidden epidemic."

"Black women who develop breast cancer are more likely to die from the disease than white women," says Nagi B. Kumar, professor at the College of Medicine at the University of South Florida and Moffitt Cancer Center. "Survival rates are also worse among blacks for colon, prostate and ovarian cancers. Why do blacks have a worse prognosis? One of the things could be their (vitamin D) blood levels are lower than others."

Kumar said several factors may explain why so many blacks are vitamin D deficient.

People get vitamin D primarily from the sun, through their diet and with over-the-counter supplements. The melanin in black skin acts as a natural sunscreen, which makes it difficult for the skin to make vitamin D. So the darker the skin, the less vitamin D you produce.

A black person requires three to five times more exposure to the sun to produce the same amount of vitamin D as a white person, Kumar says.

Blacks also have a higher incidence of lactose intolerance, so they don't use as much vitamin D fortified milk or other dairy products.

But with the risk of skin cancer, is it smart to get your D from more sun exposure?

Robert P. Heaney, professor of medicine at Creighton University Medical Center in Omaha, Neb., says no one knows for sure, but for those who aren't at an increased risk for skin cancer, about 15 minutes of unprotected sun exposure daily could help improve vitamin D deficiency.

"To put that into perspective, the human race didn't go away before the invention of sunscreen," Heaney says. Exposure to intense sunlight was mostly a year-round occurrence for our ancestors, he says.

Still, D isn't a cure for everything that ails the human race. "It's important. And our bodies need it to cope better," Heaney says. "But I don't want to promote it as a magic bullet."

On its website, the American Academy of Dermatology discourages people from getting vitamin D from sun exposure or indoor tanning because ultraviolet radiation can lead to skin cancer. The site suggests getting D from a healthy diet, which includes fortified foods, beverages and/or vitamin supplements.

Heaney recommends speaking to a physician to see whether it's necessary to take a supplement, and if it is, to determine the appropriate dose.

The only way to know whether you're vitamin D sufficient is by having a 25-hydroxyvitamin D test, also called a 25 (OH) D test.

Most people have never been tested and don't know they have a deficiency, Kumar says. But that's changing as more doctors jump on the vitamin D bandwagon.

Patients who suffer from aches and pains, which can be signs of Vitamin D deficiency, often feel better a few weeks after boosting their intake, Kumar says.

"It's very easy to raise low levels of vitamin D," he says. "If you have a deficiency, you can start to feel better in a matter of weeks."