Aging Well: Getting vitamin D from sun too risky, doctors warn

On the 'Net

Information about vitamin D:

• National Institutes of Health Office of Dietary Supplements: www.ods.od.nih.go...>

• National Osteoporosis Foundation: www.nof.org, click on Prevention and then Vitamin D, on the left side of the page.

• National Academy of Pediatrics: www.aap.org, enter "vitamin D" in the site's search engine.

For more information about skin cancer:

• Skin Cancer Foundation: www.skincancer.or...>

• American Academy of Dermatology: www.aad.org, click on the Public tab at the top of the page.

Vitamin D has been making a lot of headlines lately.

It's long been known that vitamin D helps the body absorb calcium to build healthy bones. The vitamin prevents rickets in children and osteomalacia (soft bones) in adults. Together with calcium, vitamin D also protects against osteoporosis and the risk of bone fracture.

More research, however, indicates that it also helps regulate balance and immunity and may even lower a person's risk of cancer, autoimmune disease, depression, chronic pain and other conditions (though definitive clinical trials are needed).

The growing list of known and potential benefits has fueled a debate about whether people should be getting more of the vitamin from the sun.

This is concerning to many health professionals, including local doctors, who argue that although it's difficult to gauge how much unprotected sun exposure provides sufficient vitamin D, skin cancer risk is clear.

"I do not suggest focusing on sun exposure as an adequate remedy for getting enough vitamin D," physician Brian Harrington said.

Keeping a hat on and sunscreen handy does not have to involve a vitamin D sacrifice. Supplements can boost vitamin D levels needed to maintain or improve health.

Vitamin D sources

In addition to supplements and sun, foods such as fatty fish, egg yolks and liver also are sources of vitamin D. It also is added to milk and sometimes orange juice, cereals and other products. Overall, it is difficult to get enough vitamin D from food sources.

The sun, on the other hand, can be a significant source of vitamin D. Unprotected skin makes vitamin D from ultraviolet B radiation in sunlight.

It's difficult to measure the amount of vitamin D a person's skin makes because of a variety of factors, such as skin pigment (it takes longer for darker skin to make vitamin D), time of day, cloud cover or pollution and where a person lives.

Some researchers have suggested that people can get adequate daily vitamin D from five to 30 minutes of unprotected sun exposure, but, as Harrington points out, this can be misleading.

A person in Northern Colorado would have to be naked to make sufficient vitamin D in that time frame. A person wearing shorts and a T-shirt would have to be outside without sunscreen for one to two hours to get that same amount of vitamin D, Harrington said.

The farther north people live, the harder it is for them to get enough vitamin D from sunlight in the winter.

Those at risk for vitamin D deficiency include people who spend little time in the sun - by choice or because of disability or illness - people who have very dark skin or are obese and the elderly (a person's ability to make vitamin D decreases with age).

People who do spend time outside inevitably will get some of their vitamin D from the sun because of average sunscreen habits - forgetting to wear it, not applying enough or not re-applying.

Dermatologists such as Sandra Eivins don't want to see people using vitamin D as an excuse to purposely forgo sun protection or bake themselves in a tanning bed.

"We know UV light is carcinogenic, and it causes skin cancer, and there is an epidemic of skin cancer in the U.S.," she said. "It's just too risky."

Eivins' stance reflects that of the American Academy of Dermatology, which released a statement this summer confirming its recommendation that people get their vitamin D from food and dietary supplements and not from unprotected sun exposure.

According to the Skin Cancer Foundation, skin cancer is one of the most common forms of cancer. It affects one in five Americans.

The incidence of melanoma, the deadliest form of skin cancer, continues to rise significantly.

Supplements

There is little argument about vitamin D's role in helping keep people of all ages healthy.

"It's probably one of the most important supplements to focus on," Harrington said.

The Food and Nutrition Board at the Institute of Medicine of the National Academies develops recommended daily amounts for vitamins and nutrients.

The board is revising recommendations for daily vitamin D intake, which many health organizations and researchers say are too low.

Currently, the board's recommendations range between 200 International Units and 600 IU of daily vitamin D from birth through elder years.

The National Osteoporosis Foundation, in contrast, recommends that adults younger than 50 get 400 to 800 IU and older adults get 800 to 1,000 IU.

Harrington agrees with these recommendations, particularly for post-menopausal women. Some people who have or are at risk for conditions such as osteoporosis may need more.

"There is good evidence that higher doses are beneficial," he said.

Last year, the American Academy of Pediatrics updated its guidelines for vitamin D intake in children, recommending 400 IU per day for all infants, children and adolescents.

Too much vitamin D over a long period of time can be harmful. The Food and Nutrition Board's maximum upper limits of daily vitamin D are 1,000 IU for children younger than 1 year and 2,000 IU for everyone else. Some nutrition scientists suggest that upper safe limits of vitamin D may be much higher.

People concerned about their vitamin D intake should consult their doctor and check to see how much vitamin D is contained in other supplements they are taking before adding another supplement.

The Food and Nutrition Board's updated recommendations for daily vitamin D and calcium intake are expected to be released in May 2010.

This article includes information from "Vitamin D and Bone Health," an article from the Osteoporosis Foundation and "Dietary Supplement Fact Sheet: Vitamin D," from the National Institutes of Health Office of Dietary Supplements.

Tamera Manzanares writes for the Aging Well program and can be reached at tmanzanares@nwcovna.org. Aging Well, a division of Northwest Colorado Visiting Nurse Association, is a community-based program of healthy aging for adults 50 and better. For more information, log on to www.agingwelltoday.com or call 871-7606.

Comments

Ted_Hutchinson 4 years, 6 months ago

In order to be sure you have reached the Vitamin D level associated with least incidence of Cancer, Diabetes, Heart Disease and other chronic conditions a 25(OH)D test is required. There is a charity that provide these by post at cost price as part of a vitamin D trial. http://www.grassrootshealth.net Grassrootshealth D Action

You can see from this chart Disease Incidence Prevention by Serum 25(OH)D Level http://www.grassrootshealth.net/media/download/disease_incidence_prev_chart_101608.pdf That having a 25(OH)D above 55ng/ml is associated with a lower risk of chronic illness. It's particularly important for pregnant or nursing mothers to have adequate vitamin D3 status as it's only around 55ng/ml that human breast milk contains adequate amounts of vitamin D3 for the baby. http://www.liebertonline.com/doi/pdfplus/10.1089/bfm.2008.9984 Breastfeeding Medicine Does Vitamin D Make the World Go 'Round'?

Generally it takes around 1000iu/daily for each 25lbs you weigh to attain and maintain an adequate vitamin D3 status. Reinhold Vieth in his paper "The Risk of Additional Vitamin D" http://www.grassrootshealth.net/media/download/vieth_sip_vitd_cancer_symp_2009.pdf explains how up to 10,000iu/daily Vitamin D3 is safe even where you can also get ample vitamin D from sun exposure. Generally though individuals will reguire only half that amount, around 5000~6000iu daily will see vitamin D levels around the 55ng/ml~ 135nmol/l mark in around 3 months. A postal 25(OH)D check after 3 months will show you if more is required. If so around 1000iu/daily extra should raise levels an extra 10ng/ml or 25nmol/l however people with inflammatory conditions such as celiac or diabetes may require double the normal amount to achieve the same result.

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