LEAD: Vitamin A supplements can significantly reduce the risk of death and serious complications in children with severe measles, a new study has found.

With Gleevec, the study said, the supplement speeds up the body's metabolism of the drug, reducing exposure and perhaps giving the leukemia cells more resistance.

Two studies that were designed to find out whether supplements could reduce the risk of cancer seemed to prove the opposite.

"Clinical trials are urgently needed" to test whether dietary supplements of folic acid can reduce the incidence of blood-vessel disease in men and women, they said.

Another British team found a supplement made from prickly pear cactus may reduce the nausea and dry mouth associated with hangovers, but not the dreaded headache.

Studies in the 1990s concluded that dietary supplements with CoQ reduced oxidation of low-density lipoprotein.

She was referring primarily to two large costly studies that sought to determine whether supplements of beta carotene could reduce the risk of cancer.

They say supplements can reduce the risk of chronic disease, for example.

When they looked only at adherent women, or those who took 80 percent of their pills, the supplements reduced hip fractures by 29 percent.

Other studies suggest daily supplements reduce risks of some chronic diseases and help you maintain better health overall.