Saturday, May 26, 2007

How to get more vitamin D

It’s no wonder Chicagoans are less aware and less concerned about the dangers of the sun’s rays than those in other cities, according to a recent survey by the American Academy of Dermatology.

When we do see the sun, we’re told to stay out of it, especially at midday, or reapply sunscreen to prevent premature aging and skin cancer.

Yet sun exposure is perhaps the most important source of vitamin D, because ultraviolet rays (UV) trigger vitamin D synthesis in the skin. And sunscreens with a sun-protection factor (SPF) of 8 or greater will block the UV rays that produce vitamin D, according to the National Institutes of Health.

We called on some experts to help clarify the confusion over vitamin D, an underrated nutrient that studies have shown can prevent bone diseases, cancer, immune-system disorders and even the flu.

Q. Is sunshine the best way to get Vitamin D?
A.Yes, but it’s also the most dangerous. The AAD says the harmful effects of sunlight outweigh the benefit of vitamin D production and recommends food sources and supplements.

Q.What’s the best food to eat?
A.Vitamin D is found in egg yolk, but you’d have to eat 10 eggs to get 200 IU, the minimum daily amount. A tablespoon of cod-liver oil will give you 1,360 IU per serving. Or try fatty fish such as mackerel, salmon, tuna and sardines, which all have less than 360 IU per serving. Margarine, cereal products, milk and soy milk are fortified with vitamin D, but most cheeses and ice creams generally are not.

A. healthy adult who drinks three 8-ounce glasses of fortified milk or soy milk along with a normal diet will probably be able to meet the minimum requirements of 200 IU. But many adults don’t do this, and the problem will get worse if the recommended daily levels increase from 200 IU to 2,000 IU.

Q.Can you get vitamin D from a tanning booth?
A.Yes. But there is no purposeful sun or tanning bed exposure that is “safe,” said Ashish Bhatia, an assistant professor of clinical dermatology at Northwestern University. It’s also not recommended by the AAD, given research showing a connection between indoor tanning and melanoma, the deadliest form of skin cancer and the second most common cancer among women aged 20 to 29. If you have red hair and freckles, avoid tanning beds.

If you are going to use artificial sun anyway, remember that you can get 10,000 IU of vitamin D in just 4 minutes if you’re a pale-skinned young person (older and darker people take longer), according to William Grant, director of the Sunlight, Nutrition and Health Research Center in San Francisco. “After the 10,000 IU are generated, UV tends to destroy vitamin D,” so don’t stay in tanning beds too long, Grant said.

Q.How can I safely get my D from the sun?
A.Most dermatologists say you can’t. But the National Institutes of Health suggests 10 to 15 minutes of sun exposure-sans sunscreen-on the face, arms, hands or back twice a week. (Some researchers say women should expose their arms and back and men should expose their chest for 20 minutes.) Then use a sunscreen with an SPF of at least 15 to protect the skin. (Those with darker skin require two to four times as much exposure for the same vitamin D production.)

If you’re in a sunny region of the country, you can make 1,500 IU in that 20-minute window, according to Cedric Garland of the University of California at San Diego School of Medicine. Exposure longer than about 20 minutes is counterproductive. “And people of all ages should wear a hat whenever spending more than a few minutes of the sun,” and should spend the time walking or otherwise in motion,” said Garland.

Q. What’s the best time to be in the sun for vitamin D production?
A.Midday, because the sun has more ultraviolet B radiation, which produces vitamin D, according to Grant. (That’s opposed to ultraviolet A radiation, which is a risk factor for melanoma.) Spend a shorter time in the sun at midday, rather than a longer time in the morning or afternoon unless you have Scottish ancestry, red hair and freckles. Also remember some medications are UV sensitive, Grant said.
Q. Are supplements a good alternative?
A.Yes. In fact, new findings from the Women’s Health Initiative published in the Archives of Internal Medicine showed that calcium and vitamin D supplements may also help prevent weight gain in postmenopausal women. Most multivitamins provide less than 200 IU of vitamin D; price and quantity vary by product. When consumerlab.com tested several dozen brands, they found that most had the right ingredients, broke apart properly and lacked contamination. One note of caution: A new study suggests higher intakes of calcium and vitamin D supplements lead to a greater risk of cognitive impairment in the elderly.
source:eaturesblogs.chicagotribune.com

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