Multiple sclerosis affects the central nervous system and usually occurs in early adult life. The disease, which was first diagnosed in 1849, typically affects people between the ages of 20 and 40, with women at twice the rate of men. Symptoms rarely show up before age 15 or after age 60 and for reasons not clearly understood. MS is five times more prevalent in temperate climates, such as the northern U.S., Canada, and northern Europe.
Normally, nerve fibers are surrounded by a layer of insulation called myelin. MS results when the nerve fibers of the central nervous system develop multiple patches of demyelination (removal of the myelin sheath). What seems to happen in MS is that the immune system attacks the myelin sheath, following a pattern of inflammation occurring as randomly distributed plaques in the central nervous system. The damage to the myelin sheath impairs nerve transmission, either slowing down or stopping impulses from the brain directing muscles to move. The multiple nerve sheaths that have lost their myelin covering become scarred and hardened, called sclerosis.
Multiple sclerosis is most common in Western countries where people consume large amounts of meat, dairy products, and processed foods—all foods low in essential fatty acids—and is least common in countries where diets are high in unsaturated fats, including seed oils, olive oil, oily fish, fresh fruits, and vegetables—all foods high in essential fatty acids