Vitamin D deficiency tied to host of dangers

[Guest guest]

{This post may be forwarded yon and hither}

Vitamin D deficiency tied to host of dangers

By , Globe Staff | December 30, 2004

http://www.boston.com/news/globe/health_science/articles/2004/12/30/vitamin_d_de\

ficiency_tied_to_host_of_dangers/

A growing body of scientific evidence suggests that the widespread

deficiency of vitamin D among Americans is more harmful than once

believed, increasing their risk of fractures, muscle weakness, and even

cancer as they age. In response, two key scientific panels are

considering how to close the nutrition gap without compromising another

important health campaign: the fight against skin cancer.

More than 40 percent of American adults have low blood levels of vitamin

D, which people can get from foods such as milk and salmon as well as

nutritional supplements. During nonwinter months, however, people can

also get vitamin D from standing in the sun for a few minutes several

times a week. That amount of exposure may seem trivial, but many

dermatologists worry that any sun exposure may increase the risk of skin

cancer and, more significantly, that encouraging some sun exposure will

lead some people to overdo it.

Until recently, public health officials advised people to avoid sun

exposure altogether and regarded vitamin D deficiency as far less

important, believing that the danger of low vitamin D levels was mainly

an increased risk of fractures among the elderly and a rare disease

called rickets among children. But recent research has shown that older

people with adequate vitamin D levels have better muscle control, lower

blood pressure, and fewer ills such as multiple sclerosis and arthritis,

compared with people with lower vitamin levels.

Now, a forthcoming Harvard School of Public Health study is expected to

show that adequate vitamin D levels reduce cancer risk by 30 percent,

increasing pressure on the US Department of Agriculture to raise the

recommended daily consumption of the nutrient. The new data also are

likely to add to the chorus of vitamin D advocates who say it is time to

lighten up on the anti-sun message.

" We absolutely have a huge problem with vitamin D deficiency, " said Dr.

Bess Dawson-, director of the Bone Metabolism Laboratory at Tufts

University, who argues for both more dietary vitamin D and sun exposure

just long enough to trigger the body's vitamin D machinery. " It's hard

for things to be so polarized because a little sunlight goes a very long

way in producing vitamin D. . . . I don't think there's a villain here. "

For most people, she said, 10 minutes a day of sun exposure to the face

and arms without sunblock protection is enough to trigger vitamin D

production in the skin during warm weather. However, from mid-October to

mid-March, the sun's rays in northern cities such as Boston are too weak

to generate vitamin D, causing a regionwide drop-off in blood levels

through the winter.

Vitamin D researchers say the attention to the issue is overdue.

Researchers such as Dr. Holick of Boston University School of

Medicine argue that the anti-skin cancer campaign actually made the

vitamin D deficiency worse by keeping people out of the sun while not at

the same time advocating increased vitamin D consumption in diets. Since

vitamin D is not found in many foods, and many adults are

lactose-intolerant, he believes the sun is the leading source of vitamin

D for most people.

" There hasn't been a balanced conversation about what compromise we can

reach for best protecting people for vitamin D and still protecting

against skin cancer, " said Connie Weaver, director of the Botanical

Center for Age-Related Diseases at Purdue University. " Now [vitamin D]

is getting a lot of attention. The science is driving it. "

Work in Dawson-'s lab, for example, showed that vitamin D is

important for muscle performance in older people, and those who had

higher levels could get up from a chair and walk better than those with

lower levels. As a result, Dawson- suggests that vitamin D, which

helps the body retain calcium, is important for preventing falls and

fractures as people age.

Other studies have suggested that higher vitamin D levels help protect

against colon, prostate, and breast cancer, but a long-term study of

50,000 men by researchers at Harvard School of Public Health suggests

vitamin D may reduce the risk of all cancers. The study, which is still

under review for publication, found that men who consumed higher levels

of vitamin D reduced their overall cancer risk by at least 30 percent,

according to lead author, Ed Giovannucci. The findings were

statistically significant, he said, and a separate study of women is

expected to produce similar results.

Giovannucci, who declined to discuss details of the study before

publication, said cells in general use vitamin D to remain normal,

making them less likely to grow out of control the way a tumor does. If

everyone had adequate vitamin D levels in their bloodstreams, he said,

" It would be equivalent to eliminating a big portion of cancer. "

The American Academy of Dermatology, a leader in the anti-skin cancer

crusade, held a conference last summer on how to respond to the findings

about the risks of vitamin D deficiency. The group's conclusions have

not yet been released, but it is expected to recommend increased vitamin

D consumption, especially for the elderly, but only through food and

vitamins.

Research has shown that sunburns, particularly during childhood,

increase the risk of developing skin cancer. Though the evidence is less

clear for shorter exposures to sunlight, the dermatology group advises

sunscreen and clothing protection for anyone in the sun 20 minutes or

longer. And they fear that any encouragement to go into the sun will

cause people to be unprotected for much longer.

" The public would love to have the message that they should go to the

tanning booths or go to the beach " without sunscreen, but that isn't

safe, said Dr. Barbara Gilchrest, chairwoman of the dermatology

department at Boston University School of Medicine. Gilchrest said

people worried about low vitamin D levels should take a vitamin supplement.

Earlier this month, the scientific panel that advises the USDA on

nutrition met on whether to recommend increasing the daily consumption

of vitamin D. Current guidelines are based on 1997 science, when little

was known about the nutrient's role in muscle strength or cancer protection.

In addition, nutrition specialists were concerned that excessive vitamin

D could also be dangerous, so the USDA approved daily vitamin D

consumption of no more than 600 international units for people over 70

and as little as 200 for those under 50. Today, vitamin D researchers

such as Dr. Finkelstein of Massachusetts General Hospital suggest

people of all ages should get 800 units of vitamin D or more, the

equivalent of eight cups of milk or two vitamin D supplements.

The Food and Nutrition Board of the Institute of Medicine, as the

government advisory panel is known, has not decided whether to open a

formal review of the science of vitamin D, but the board's director,

Meyers said there appeared to be plenty of support among

scientists. Its recommendations would then be used by the USDA to change

its nutritional advice to the country.

can be reached at allen@....

© <http://www.boston.com/help/bostoncom_info/copyright>2004 The New York

Times Company

The material in this post is distributed without profit to those

who have expressed a prior interest in receiving the included

information for research and educational purposes.

For more information go to:

http://www4.law.cornell.edu/uscode/17/107.html

<http://oregon.uoregon.edu/%7Ecsundt/documents.htm>

http://oregon.uoregon.edu/~csundt/documents.htm

<http://oregon.uoregon.edu/%7Ecsundt/documents.htm>

If you wish to use copyrighted material from this email for

purposes that go beyond 'fair use', you must obtain permission

from the copyright owner.