I'm Gwen Outen with the VOA Special English Health Report.
Too much sun can cause skin cancer. Too much vitamin D can also make you sick. Yet a study suggests that sunlight and vitamin D may help some people with lung cancer live longer.
Vitamin D helps build strong teeth and bones. Foods such as oily fish and egg yolks are high in vitamin D. But not many foods naturally are. So extra vitamin D is often added to milk products. Some people get more with vitamin products.
Another way is with the sun. Vitamin D is known as the "sunshine vitamin." The body produces it through the skin from the ultraviolet radiation of the sun.
Researchers from Harvard University led a study of four hundred fifty-six people. These men and women had been treated for lung cancer in Boston, Massachusetts. The cancers had been found early. Doctors operated to remove them. The average age of the patients was sixty-nine. Forty percent were smokers.
Researchers asked the people what they ate, what vitamins they took and what time of year their operations had taken place.
Some had high levels of vitamin D intake and had their operations during summertime, when there is lots of sun. Others had low levels, and were operated on in winter.
The researchers found that thirty percent of the people in this second group were alive five years after their operation. Forty-six percent were disease-free.
But patients with the highest vitamin D intake and summer operations had higher survival rates. Seventy-two percent were still alive after five years. And eighty-three percent were disease-free.
The findings were presented at a meeting of the American Association for Cancer Research. Other studies are needed to confirm them.
Harvard researcher Wei Zhou says studies on animals have shown that vitamin D may be able to act against some cancers. He says the new study does not suggest that people should try to time their cancer surgery for a particular season. But he says increasing the use of vitamin D before such treatment could help.
Lung cancer is the most common cancer around the world, with more than one million new cases each year. And it kills more people than any other cancer. About sixty percent of those who get lung cancer die within a year. The major preventable cause is the use of tobacco.
This VOA Special English Health Report was written by Cynthia Kirk. Our reports are online at WWW.51VOA.COM. I'm Gwen Outen.