News Story - Vitamin D may help curb breast cancer, study finds

Vitamin D may help curb breast cancer, study finds

Breast cancer patients with low levels of vitamin D were much more
likely to die of the disease or have it spread than patients getting
enough of the nutrient, a study found — adding to evidence the
"sunshine vitamin" has anti-cancer benefits. The results are sure to
renew arguments about whether a little more sunshine is a good thing.

The skin makes vitamin D from ultraviolet light. Too much sunlight can
raise the risk of skin cancer, but small amounts — 15 minutes or so a
few times a week without sunscreen — may be beneficial, many doctors
believe.

While the vitamin is found in certain foods and supplements, most
don't contain the best form, D-3, and have only a modest effect on
blood levels of the nutrient. That's what matters, the Canadian study
found.

Only 24 percent of women in the study had sufficient blood levels of D
at the time they were first diagnosed with breast cancer. Those who
were deficient were nearly twice as likely to have their cancer recur
or spread over the next 10 years, and 73 percent more likely to die of
the disease.

"These are pretty big differences," said study leader Dr. Pamela
Goodwin of Mount Sinai Hospital in Toronto. "It's the first time that
vitamin D has been linked to breast cancer progression."

But people shouldn't start downing supplements, she warned. Experts
don't agree on how much vitamin D people need or the best way to get
it, and too much can be harmful. They also don't know whether getting
more vitamin D can help when someone already has cancer.

"We have no idea whether correcting a vitamin D deficiency will in any
way alter these outcomes," said Dr. Julie Gralow, a cancer specialist
at the University of Washington in Seattle.

The study was released Thursday by the American Society of Clinical
Oncology and will be presented at the group's annual meeting later
this month.

Lots of earlier research suggests vitamin D may help prevent prostate,
breast and especially colon cancer. In lab and animal tests, vitamin D
stifles abnormal cell growth, curbs formation of blood vessels that
feed tumors and has many other anti-cancer effects.

Other evidence: People who live in northern regions of the world have
higher cancer rates than those living closer to the equator, possibly
because of less sunshine and vitamin D.

The Canadian researchers wanted to see whether it made a difference in
survival. They took blood from 512 women at three University of
Toronto hospitals between 1989 and 1995, when the women were first
diagnosed with early-stage breast cancer.

A decade later, 83 percent of those who had had adequate vitamin D
blood levels were alive without extensive spread of their cancer,
versus 79 percent of those whose vitamin D levels were insufficient
and 69 percent of those who were deficient, as defined by widely used
medical standards for measuring intake.

One red flag: The few women with the very highest levels of vitamin D
seemed to have worse survival.

Though the study was too small and those results were not conclusive,
"there may be an optimal level of vitamin D in women with breast
cancer and it may be possible to take too much," Goodwin said.

The federal government says up to 2,000 international units of vitamin
D a day seems OK. Taking 800 units per day will, on average, raise
blood levels to the middle of the range that seems best for bone and
general health, Goodwin said.

Vitamin D is in salmon and other oily fish, and milk is routinely
fortified with it, but dietary sources account for little of the
amount of D circulating in the blood, experts say.

"It's very hard to make a recommendation" because how much difference
a supplement makes depends on someone's baseline level, which also can
be affected by sunlight, skin type and time of year, she explained.

Doctors do suggest breast cancer patients get their vitamin D levels
checked to see whether they are deficient. The simple blood test is
available in many hospitals and labs for about $25, Goodwin said.

Dr. Nancy Davidson, a Johns Hopkins University cancer specialist who
is president of the oncology society, said those tests are growing in
popularity, even in ordinary medical care.

"Rightly or wrongly, I'm increasingly seeing physicians who are
measuring this," she said.

The Canadian study was paid for by the Breast Cancer Research
Foundation in New York, established by cosmetics magnate Evelyn
Lauder.

"It's a very provocative paper. It's confirmatory of a tremendous
amount of evidence that vitamin D is an important component of
health," said Dr. Larry Norton, chief of breast cancer programs at
Memorial Sloan-Kettering Cancer Center in New York and a medical
adviser to the foundation.

Breast cancer is the most common cancer in women. About 184,450 cases
and 40,930 deaths from the disease are expected in the United States
this year.

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On the Net:

Government vitamin information:

http://ods.od.nih.gov/factsheets/vitamind.asp

Cancer conference: http://www.asco.org