BETHESDA, MD: Turns out that beta carotene, a popular vitamin supplement that has been touted as a cancer and heart disease preventative, not only does no good, it may actually increase the risk of those diseases among people who smoke or work with asbestos. The National Cancer Institute, which sponsored two newly concluded studies reaching that result, found the findings so important that it called a press conference today to make the news public. NCI said a study involving smokers was halted 21 months early because the damage was so marked. "The message here is, basically, eat your fruits and vegetables," says TIME's Christine Gorman. "You can't get around it." Gorman points out that because laboratory tests had shown that beta carotene slowed the growth of malignant tumors, millions of people began using it as a vitamin supplement. "It took a while to test that hypothesis. And now we know. You can't fool Mother Nature. You have to eat your peas and carrots."