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---------------------------------------------------------------------- Getting Vitamin C on the Brain ---------------------------------------------------------------------- NEW YORK (Reuters) -- Vitamin C levels are 10 times higher in the brain than they are elsewhere in the body, and now researchers think they know the reason why. A particular chemical form of vitamin C -- called dehydroascorbic acid -- can slip past the blood brain barrier, resulting in higher concentrations of the antioxidant in the central nervous system. "Our findings in this study suggest that vitamin C concentrations in the brain could be increased by increasing the blood concentration of dehydroascorbic acid," reported lead author Dr. David Agus, an oncologist at the Memorial Sloan-Kettering Cancer Center in New York. Manipulating vitamin C levels in the brain may turn out to be helpful in combating Alzheimer's disease or other neurological disorders. Vitamin C tends to mop up free radicals, damaging particles that might contribute to neurological damage, according to the report in the Journal of Clinical Investigation. "We now know how to get large amounts of an antioxidant into the brain," said Agus. Ascorbic acid, the form of vitamin C absorbed from the intestines, is unable to cross the blood brain barrier. The barrier is a network of capillaries that prevents most chemicals from gaining access to the sensitive central nervous system. However, Agus and colleagues found that when ascorbic acid was converted to dehydroascorbic acid it could be ferried across the blood brain barrier by a transporter molecule. Such transporters are found on cells lining the blood brain barrier, and can transport compounds into the brain and spinal cord. In the case of dehydroascorbic acid it was the GLUT1, which normally transports glucose, that moved the vitamin. Once inside the brain dehydroascorbic acid is converted back into ascorbic acid -- thus explaining the mystery of high vitamin C concentrations in the brain. By Theresa Tamkins SOURCE: Journal of Clinical Investigation (1997;100) 1997 Reuters Health eLine <http://www.medscape.com/reuters/tue/t1201-1f.html> ---------------------------------------------------------------------- janet [log in to unmask]