Anaheim, Calif. — Getting enough vitamin D may be a matter of life or death
– a provocative new study suggests that it plays an important role in surviving
People can obtain the nutrient from their food, vitamin pills or being out
in the sunshine. Researchers found that the lung-cancer patients with high intake
who had surgery during the summer were more than twice as likely to be alive
five years later than those with low levels who had operations in winter.
It is one of several recent studies to show the benefits of the “sunshine
vitamin” against cancer.
“There are a lot of data emerging from various areas suggesting it is
important,” said Dr. Edward Giovannucci, professor of nutrition and epidemiology
at the Harvard School of Public Health.
He helped conduct what is believed to be the first human study to look at
vitamin D and lung cancer survival. The results were reported Tuesday at an
American Association for Cancer Research conference in Anaheim.
“This is a very interesting study. It's a new trend – looking at
dietary factors as they relate to survival,” not just the risk of getting
a certain cancer, said Dr. Michael Thun, chief epidemiologist at the American
Cancer Society, who had no role in the research.
Vitamin D is made by the skin from sunlight. Getting enough from diet alone
is tough – fish and fortified milk are the main sources. Supplements are
controversial, because too much D can cause medical problems, but many scientists
think the recommended daily level of 400 international units is too low.
The nutrient has many features that could explain its possible benefit against
cancer, such as stifling cell growth. Doctors had seen evidence suggesting that
it prevents some cancers, and they wanted to know if it also affected survival.
Led by Harvard University's Dr. David Christiani, they studied 456 consecutive
patients with early-stage lung cancer at Massachusetts General Hospital, Brigham
and Women's Hospital and Dana-Farber Cancer Institute. Patients were interviewed
about diet, supplements and timing of their cancer surgery, which was thought
to be another indicator of their vitamin D levels.
Those who had high vitamin D levels and summer operations fared the best: five-year
survival was 72 per cent versus 29 per cent for those who had the lowest levels
of the nutrient and winter surgery.
This does not mean that people should delay or try to time operations, but
taking vitamin D supplements about the time of surgery might be a good idea,
said Wei Zhou, a Harvard researcher who presented the study results.
If verified by larger experiments, “this would be considered an important
gain,” said Dr. Thun of the cancer society. “A benefit of this size
is important for this highly lethal disease.”
Lung cancer is the world's top cancer killer. About 172,500 new cases and 163,510
deaths are expected this year in the United States, and more than 1.3 million
cases and nearly 1.2 million deaths worldwide