Washingtonians Need More Vitamin D

SEATTLE (PI) -- Browsing through the vitamin aisle at a local Walgreens, a woman tossed a box of multivitamin pills into her basket. Listed among the bevy of nutrients was vitamin D, which, the woman admitted, she didn't really think twice about.

"It's just one of the whole list of things I'm sure I'm not getting in my diet, so I might as well get it in the pill," she said.

She's right -- she's almost certainly not getting enough in her diet. But she's probably not getting enough from her supplement either. And neither are most people in Seattle, where sunshine -- a major contributor to the body's production of vitamin D -- can be a distant memory during much of the winter.

In fact, local experts say Seattleites need far more vitamin D than the Food and Drug Administration's recommendations -- perhaps twice as many international units, and maybe even more than that.

"Vitamin D is good for bone health, immune health and cancer prevention," said Kelly Morrow, nutrition instructor at Bastyr University. "But most of the year, we're just not getting enough vitamin D."

Often called the "sunshine vitamin," vitamin D is made in the body after exposure to ultraviolet rays from the sun. It helps with calcium absorption, key for growing bones and preventing osteoporosis.

Studies in California and Massachusetts have shown vitamin D can help fight prostate cancer. Scientists also are looking into the vitamin's role in boosting the immune system and protecting against other cancers, including breast and ovarian.

Lower-than-recommended levels could lead to increased risk of cancers, multiple sclerosis and type 1 diabetes, doctors say.

Morrow said people living in the United States above 35 degrees latitude -- which is just above most of the Southern states -- get so little sun in the winter, they can't produce vitamin D from November through February. Seattle, much farther north at close to 48 degrees latitude, is sun-deficient about seven months a year.

The debate is not about whether people need more vitamin D. It is about how much more. Physicians believe the FDA recommendations, last updated in 1997, will change soon to reflect the growing need for more vitamin D.

"We do have less sunlight than most of the country and more cloud cover, but there's still a bit of a debate about vitamin D levels," said Susan Ott, an associate professor of medicine at the University of Washington.

At a national conference she attended in December, Ott said there wasn't agreement among physicians on the proper amount the public should take. The FDA recommends a daily intake of 200 international units (IU) for adults up to age 50, 400 IU for adults 51 to 70 and 600 IU for those 71 and older. An 8-ounce serving of milk provides 100 IU of vitamin D. A standard multivitamin supplement contains 400.

Ott recommends more. Everyone, especially those living in Northern areas with little sunlight, needs at least double the FDA's recommended amount, she said. This is especially true for people age 70 and over, whose skin has stopped producing vitamin D, she said.

In a recent interview with WebMD, Michael Holick, head of the vitamin D research lab at Boston University, said the optimal daily dosage for preventing disease is closer to 1,000 IU, an amount available in some supplements found at local pharmacies. Or drink 10 glasses of milk a day to get what he believes is the needed amount of vitamin D.

According to the Food and Nutrition Board of the Institute of Medicine, which is part of the National Academy of Sciences, men, women and children age 1 and older can safely tolerate up to 2,000 IU of vitamin D a day.

Skin color also plays a role in the amount of vitamin D needed, with darker skin acting as a natural sunscreen and absorbing less of the sun's rays than lighter skin, said Morrow. And anyone who wears sunscreen, while appropriately fighting skin cancer, is also preventing much-needed vitamin D from being absorbed by the skin.

A study published in the January issue of the online journal Nature Immunology showed short, unprotected stints in the sun actually are good for the skin and help boost vitamin D levels. Researchers at Stanford University found the sun was the best way to get skin-protecting cells to develop, but others say the findings are preliminary and clinical trials still are needed for confirmation.

For now, just 10 to 15 minutes of sun exposure sans sunscreen during the summer is recommended, before slathering or spraying on the protectant.

But the rest of the year, vitamin supplements and food are the answer. Vitamin D is found in food such as fish, liver and milk, which has been fortified with the vitamin since the 1930s.

One common source of vitamin D has been cod liver oil, but according to Ott, cod liver oil contains vitamin A, which has been shown in studies to be bad for bones, and increases the number of fractures.

"It's counterproductive and I don't recommend cod liver oil to my patients," she said.

What is recommended is having vitamin D levels tested regularly, just as cholesterol levels are checked. Then, each individual can determine just how much vitamin D is needed.

But limited sun exposure and increased foods and supplements are needed, especially in Seattle.

"Companies are modifying vitamin D to help treat cancers," said Ott. "We're finding out more and more, which is just one more reason why people shouldn't be deficient in vitamin D."
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