Alpha-carotene & cancer.Call it the beta-carotene quandary. Researchers are scrambling to figure out why foods rich in beta-carotene seem to reduce the risk of lung cancer lung cancer, cancer that originates in the tissues of the lungs. Lung cancer is the leading cause of cancer death in the United States in both men and women. Like other cancers, lung cancer occurs after repeated insults to the genetic material of the cell. while high doses of beta-carotene supplements seem to Increase the risk. One theory--that massive doses of betacarotene keep people from absorbing other substances in fruits and vegetables that may be the real protectors--now has new support from a study from the National Cancer Institute in Bethesda, Maryland Bethesda is an urbanized, but unincorporated, area in southern Montgomery County, Maryland, just Northwest of Washington, D.C. It takes its name from a church located there, the Bethesda Presbyterian Church, built in 1820 and rebuilt in 1850, which in turn took its name from . Regina Ziegler and co-workers analyzed the diets that 763 men recalled eating before they were diagnosed with lung cancer. She compared the diets to those of 564 similar men with no cancer. The results: Lung cancer was more closely associated with a low intake of alpha-carotene than with a low intake of beta-carotene. Among the men who were current or recent smokers, a diet poor in beta-carotene increased the risk of lung cancer by 60 percent, while a diet poor in alpha-carotene roughly doubled the risk. Alpha- and beta-carotene usually occur in the same foods. Only seven of the men had frequently eaten foods that are especially rich in beta-carotene (like spinach spinach, annual plant (Spinacia oleracea) of the family Chenopodiaceae (goosefoot family), probably of Persian origin and known to have been introduced into Europe in the 15th cent. and other leafy leaf·y adj. leaf·i·er, leaf·i·est 1. Covered with or having leaves. 2. Consisting of leaves: Spinach is a leafy green vegetable. 3. Similar to or resembling a leaf. greens) and had infrequently in·fre·quent adj. 1. Not occurring regularly; occasional or rare: an infrequent guest. 2. eaten foods that are rich in both carotenes (like carrots and sweet potatoes sweet potato, trailing perennial plant (Ipomoea batatas) of the family Convolvulaceae (morning glory family), native to the New World tropics. Cultivated from ancient times by the Aztecs for its edible tubers, it was introduced into Europe in the 16th cent. ). All seven got lung cancer. "It is premature to conclude that alphacarotene is protective in humans," says Ziegler. "The most rational way to reduce lung cancer risk is to eat a variety of vegetables and fruits and, most important, to not smoke." Journal of the National Cancer Institute 88: 612, 1996. |
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