Some Seek Guidelines to Reflect Vitamin D's Benefits

[Guest guest]

By Rob Stein

Washington Post Staff Writer

Friday, July 4, 2008; Page A01

A flurry of recent research indicating that Vitamin D may have a dizzying

array of health benefits has reignited an intense debate over whether

federal guidelines for the " sunshine vitamin " are outdated, leaving millions

unnecessarily vulnerable to cancer, heart disease, diabetes and other

ailments.

The studies have produced evidence that low levels of Vitamin D make men

more likely to have heart attacks, breast and colon cancer victims less

likely to survive, kidney disease victims more likely to die, and children

more likely to develop diabetes. Two other studies suggested that higher

Vitamin D levels reduce the risk of dying prematurely from any cause.

In response to these and earlier findings, several medical societies are

considering new recommendations for a minimum daily Vitamin D intake, the

American Medical Association recently called for the government to update

its guidelines, and federal officials are planning to launch that effort.

But many leading experts caution that it remains premature for people to

start taking large doses of Vitamin D. While the new research is

provocative, experts argue that the benefits remain far from proven. Vitamin

D can be toxic at high doses, and some studies suggest it could increase the

risk for some health problems, experts say. No one knows what consequences

might emerge from exposing millions of people to megadoses of the vitamin

for long periods.

" The data are intriguing and serve as, no pun intended, food for further

fruitful research, " said Frances Picciano, at the Office of Dietary

Supplements of the National Institutes of Health. " But beyond that, the data

are just not solid enough to make any new recommendations. We have to be

cautious. "

The current clash is the latest in a long, often unusually bitter debate.

Some skeptics question whether funding by the tanning, milk and vitamin

industries is biasing some advocates. Frustrated proponents accuse skeptics

of clinging to outdated medical dogma.

" It feels kind of ridiculous working in this field sometimes, " said Reinhold

Vieth, a professor of nutritional sciences and pathobiology at the

University of Toronto. " Every week, I get interviewed about the next

important publication about Vitamin D. But this field remains mired in the

muck. "

Vieth is one of a small but vocal cadre of researchers pushing doctors and

patients to stop waiting for new official guidelines. Physicians should

routinely test their patients for Vitamin D deficiencies, and more people --

especially African Americans -- should take supplements and increase their

exposure to the sun, they say.

" The bottom line is we now recognize that Vitamin D is important for health

for both children and adults and may help prevent many serious chronic

diseases, " said F. Holick, a professor of medicine, physiology and

biophysics at Boston University.

Scientists have long known that Vitamin D is a vital nutrient the skin

produces when hit by ultraviolet light from sunlight and other sources. The

amount of Vitamin D produced varies, depending on where the person lives,

skin pigment, age and other factors. African Americans and other

dark-skinned people, and anyone living in northern latitudes, make far less

than other groups.

With people spending more time indoors surfing the Web, watching television,

working at desk jobs, and covering up and using sunblock when they do

venture outdoors, the amount of Vitamin D that people create in their bodies

has been falling. Milk and a few other foods are fortified with Vitamin D,

and it occurs naturally in others, such as fatty fish, but most people get

very little through their diets.

" Humans evolved in equatorial Africa wearing no clothes, " said P.

Heaney, a leading Vitamin D researcher at Creighton University in Omaha.

" Now we get much less direct sunlight, and so we don't make nearly as much

Vitamin D. "

A number of studies have found that deficiencies may be common, with perhaps

half of adults and children having what some consider inadequate levels.

Federal guidelines call for people to get 200 to 600 international units a

day, depending on age and other factors. But those recommendations were last

updated in 1997 and were aimed primarily at preventing bone diseases, such

as rickets in children and osteoporosis in the elderly.

Since then, studies have indicated that Vitamin D offers a plethora of

health benefits, possibly protecting against heart disease, many forms of

cancer, immune system disorders such as multiple sclerosis and rheumatoid

arthritis, infectious diseases such as tuberculosis and the flu, and perhaps

mental illnesses including schizophrenia and depression.

" Vitamin D has a global effect on many systems, " said Bruce Hollis, a

professor of pediatrics, biochemistry and molecular biology at the Medical

University of South Carolina.

The Canadian Cancer Society upped its recommendation to 1,000 units a day

last year. Hollis and others believe Americans should routinely consume at

least 2,000 international units a day.

" The first thing we'd see is a reduction by 80 percent in the incidence of

Type 1 diabetes, " said Cedric Garland, a professor of family and preventive

medicine at the University of California at San Diego. " The next thing we'd

see is a reduction by about 75 percent of all invasive cancers combined, as

well as similar reductions in colon cancer and breast cancer, and probably

about a 25 percent reduction in ovarian cancer. "

Holick urges people to take 1,000 international units a day along with a

multivitamin with 400 international units, as well as exposing their arms

and legs to the sun for about 15 minutes several times a week.

But others have reservations. Dermatologists worry that encouraging people

to get unprotected sun exposure or use tanning salons may increase the rate

of skin cancer.

" We're in the middle of a skin cancer epidemic, " said C. Hanke,

president of the American Academy of Dermatology. " Tanning is risky and

dangerous behavior. Ultraviolet light is classified as a carcinogen. We need

to protect our skin. "

Studies of other nutrients, such as Vitamin E, beta carotene and folate,

have previously produced similarly promising findings only to turn out to be

ineffective or even possibly dangerous, others say.

" We've gotten very excited in the past, " said Alice Lichtenstein, a

professor of nutrition at Tufts University who is a spokeswoman for the

American Heart Association.

" It seems like an easy answer: We don't have to worry about losing weight or

exercising. While I know the literature on Vitamin D is exploding, I think

we have to be cautious until we've done the proper studies, " Lichtenstein

said.

Other skeptics go further, saying the Vitamin D already added to foods may

be fueling increases in chronic diseases, such as diabetes and obesity.

" We call it a vitamin, but it's really a steroid, " said Trevor G. Marshall,

a molecular biologist at Murdoch University in Australia. " It's not

something we should be playing with. "

While still cautious, another skeptic, Leonard Lichtenfeld, deputy chief

medical officer at the American Cancer Society, acknowledges that the

evidence for Vitamin D is getting harder to ignore.

" I had a fair degree of skepticism. But now, while not a full-blown

proponent, I believe it's definitely an area that needs more attention, "

Lichtenfeld said.

The National Academies' Institute of Medicine is negotiating with NIH and

the Agriculture Department to make Vitamin D the first nutrient to be

reassessed under a new system of evaluating nutritional requirements.

" Within the last four or five months, it's become a much more intensive

dialogue, " said of the institute's Food and Nutrition

Board. She cautioned, however, that the review, which could begin as early

as the fall and take more than year, might leave the current recommendation

unchanged.

" Some would argue there are significant new data about Vitamin D, "

said. " That doesn't mean that would change the requirement. But it implies a

timely review is in order. "