WASHINGTON Vitamin D may extend the lives of people with colon and rectal cancer, according to a study published on Wednesday suggesting another health benefit from the so-called sunshine vitamin.
Previous research has indicated that people with higher levels of vitamin D may be less likely to develop colon and rectal cancer, also called colorectal cancer.
The new study led by Dr. Kimmie Ng of Dana-Farber Cancer Institute in Boston involved 304 men and women diagnosed with colorectal cancer from 1991 to 2002, to see if higher levels of vitamin D in the patients affected their survival chances.
In fact, that turned out to be the case.
The researchers in the study, published in the Journal of Clinical Oncology, used blood samples to determine vitamin D levels of the patients, and they were tracked for an average of about 6-1/2 years.
Those in the highest 25 percent of vitamin D levels were about 50 percent less likely to die during the study from their cancer or any other cause compared to the patients in the lowest 25 percent of vitamin D levels.
During the study, 123 of the patients died, 96 of them from colorectal cancer.
"It's probably premature to say that we should be recommending this as treatment for colon cancer, but vitamin D should definitely be studied in the setting of a clinical trial to see if it has any benefit to treating colorectal cancer," Ng said in a telephone interview.
Ng said a clinical study is being planned to test vitamin D as part of colorectal cancer treatment. It would involve patients who already have gotten their cancer surgically removed, with some getting chemotherapy with vitamin D after surgery and the others getting just the standard chemotherapy.
"Definitive evidence of a benefit of vitamin D in treating colon cancer would have to come from a clinical trial," Ng said.
The body makes vitamin D when the skin is exposed to sunlight, thus earning its nickname the "sunshine vitamin." Milk commonly is fortified with it, and it is found in fatty fish like salmon. But many people do not get enough of it.
Vitamin D helps the body absorb calcium and is considered important for bone health. In adults, vitamin D deficiency can lead to osteoporosis, and it can lead to rickets in children.
A number of recent studies have indicated vitamin D also may offer a variety of other health benefits, including protecting against types of cancer such as breast cancer, peripheral artery disease and tuberculosis.
According to the American Cancer Society, about 1.2 million new cases of colorectal cancer are diagnosed a year, and the disease kills about 630,000 people a year, accounting for 8 percent of all cancer deaths.
In addition, a study published on June 9 in the journal Archives of Internal Medicine found that men with low levels of vitamin D had an elevated risk for a heart attack.
The American Medical Association, the largest U.S. doctors group, voted this week to urge the Food and Drug Administration to re-examine recommendations for vitamin D intake in light of new scientific findings showing its benefits.