Vitamin D 'can fight MS' by blocking path of destructive cells to the brain Disease is most common far from the equator, Baltimore researchers found Tests on mice suppressed amounts of T-cells found near brain and spine Scientists warn care needs to be taken as Vitamin D is a hormone Breakthrough? Scientists at Baltimore University found MS is rare near the equator Vitamin D may be able to combat multiple sclerosis, researchers said yesterday. They discovered that it can block the migration of destructive cells to the brain, which causes the condition. This could help explain anecdotal reports that the "sunshine vitamin" prevents or eases symptoms. MS is most commonly found far from the equator, where there is less sunshine to trigger production of vitamin D in the skin. The disease is caused by the body's own immune defences damaging myelin, a fatty insulating sheath that surrounds nerve fibres and is vital to the proper transmission of nerve signals. Destruction of myelin leads to symptoms ranging from numbness to blurred vision and paralysis. Researchers simultaneously gave mice the rodent form of MS and a high dose of vitamin D. They found symptoms of the disease were suppressed. "Vitamin D might be working not by altering the function of damaging immune cells but by preventing their journey into the brain," said lead scientist Anne Gocke, of Johns Hopkins University in Baltimore. In a person with MS, immune system cells called T-cells are primed to travel out from the lymph nodes and seek and destroy myelin in the central nervous system. While large numbers of T-cells were found in the bloodstreams of the mice, very few were detected in their brains and spinal cords. 'Vitamin D doesn't seem to cause global immunosuppression,' said Dr Gocke. 'What's interesting is that the T-cells are primed, but they are being kept away from the places in the body where they can do the most damage.' Tests: Researchers found Vitamin D suppressed symptoms of blurred visions and mobility issues in mice The vitamin may slow production of a sticky substance that allows the T-cells to attach onto blood vessel walls, she added. This may help to keep them in circulation and prevent their migration to the brain. Once vitamin D was withdrawn from the mice, MS flare-ups occurred very quickly, said the researchers, whose findings appear in the journal Proceedings of the National Academy of Science. Peter Calabresi, a professor of neurology at Johns Hopkins and co-author of the study, said: 'Vitamin D may be a very safe therapy, but we still have to be careful with it. It's not just a vitamin. It's actually a hormone.' A clinical trial testing the effect of vitamin D supplements on patients with MS is currently under way at Johns Hopkins University.