The Effects of Vitamins on Cancer
Reported November 01, 2007
(Ivanhoe Newswire) — What effects — if any — do vitamins have on cancer?
Two new studies have some answers. The first one from researchers at the University of Texas M.D. Anderson Cancer Center in Houston shows a derivative of vitamin A, called retinoic acid, can reduce the growth of lung cells in a group of former heavy smokers.
Even after smokers quit, they are still at an increased risk for lung cancer. One theory for this is lung cells damaged during years of smoking may keep growing and evolve into cancer even after a person quits smoking. Previous studies have suggested retinoids may prevent lung cancer in former smokers. They have also been shown to slow the growth of cancer cells in lab experiments.
In a second study, researchers report they found no relationship between levels of vitamin D and the overall risk of dying from cancer. They did show, however, vitamin D levels are associated with a decreased risk of dying from colorectal cancer.
Researchers from the National Cancer Institute in Bethesda, Md., analyzed data from 16,818 participants aged 17 and older to look at the relationship between levels of circulating vitamin D in the blood and cancer mortality. After 10 years, 536 of the participants had died, and researchers could find no evidence those who died had lower vitamin D than those who survived. Study participants with colorectal cancer and high levels of vitamin D, however, were 72-percent less likely to die than patients with the same cancer and lower vitamin D levels.
An accompanying editorial from researchers from the National Institutes of Health discusses the complicated relationship between nutrients and cancer. These findings must be put into the context of total diet and lifestyle. There are many risk factors other than diet for colorectal cancer, and there are many possible dietary risk factors other than vitamin D that have been linked to cancer risk, the editorialists write.
SOURCE: Journal of the National Cancer Institute, 2007;99: 1563-1565, 1565-1567, 1594-1602, 1603-1612
