Multiple Sclerosis and vitamin d link

MSMultiple sclerosis is an immune-mediated inflammatory and neurodegenerative condition of the central nervous system. Its symptoms include weakness, visual problems, and impaired coordination. Although its causes remain unknown, scientists suspect that multiple sclerosis may represent an autoimmune condition. MS is a central nervous system disorder marked by decreased nerve function with initial inflammation of the protective myelin nerve covering and eventual scarring. Symptoms and severity of symptoms vary widely and may progress into episodes of crisis alternating with episodes of remission.

Investigators have established a strong link between multiple sclerosis incidence and geographic location, noting that areas with abundant sun exposure or plentiful dietary fish intake experience reduced risk. Multiple sclerosis occurs more often in people who lived in northern areas of Europe and North America during childhood, and less often in people who live closer to the equator. Individuals appear to retain the level of risk associated with the area in which they lived until age 15, even if they moved to a different area later in life.

In Switzerland, multiple sclerosis rates are higher at low altitudes and lower at high altitudes, where UV light is more intense. In Norway, multiple sclerosis rates are higher inland, but much lower near the coast, where vitamin D3-rich fish is consumed regularly. Vitamin D, obtained through both sun exposure and diet, may be the factor responsible for the link between geography and multiple sclerosis risk.

Evidence suggests that vitamin D  may decrease the lifetime risk of multiple sclerosis in women. Experimental data suggest the white matter of the brain that multiple sclerosis affects contains vitamin D receptors, and inadequate vitamin D during early development may predispose these cells to an early demise.

Researchers have noted that administering the active form of vitamin D-1,25-dihydroxyvitamin D-to animals can completely protect them against an experimentally induced form of multiple sclerosis. According to the investigators, the active form of vitamin D may act as a selective immune system regulator that works to inhibit autoimmune disease.

Later research indicated that 1,25-dihydroxyvitamin D also helped to reduce multiple sclerosis disease activity in mice with an experimentally induced model of the disease. Based on this animal data, Dutch researchers postulated that multiple sclerosis patients may similarly benefit from optimal serum concentrations of vitamin D. Optimal vitamin D levels might not only help achieve immune-mediated suppression of disease activity, but also help decrease complications related to multiple sclerosis, such as muscle weakness, osteoporosis, and bone fractures.

Vitamin D linked to lower MS risk

A study provides the most compelling evidence yet that vitamin D, the so-called sunshine vitamin, may protect against the neurological disease multiple sclerosis (MS). Harvard University researchers who reviewed the medical data of more than seven million US military personnel found the risk of MS fell dramatically as the level of the vitamin circulating in the blood rose. The effect was only seen in Caucasians; the data in the study for African Americans and people of Hispanic descent was inconclusive. The relationship was particularly strong in the under-20 age group, according to the study published today in the Journal of the American Medical Association.

vit DIndividuals who ranked in the top 20% of the sample for vitamin D levels had a 62% lower risk for the chronic autoimmune disease than those in the bottom 20%. The study also found that there was a 41% decrease in risk for MS with every increase of 50 nanomoles per litre of circulating vitamin D.

"The study strongly suggests that vitamin D has a protective effect, and one which could potentially prevent thousands of cases of MS," says co-author Alberto Ascherio, associate professor of nutrition and epidemiology at the Harvard School of Public Health.

The findings add to a growing body of evidence that vitamin D could reduce the incidence of the incurable condition. But Ascherio says it is still insufficient to make the case for an increase in the recommended daily dietary intake of vitamin D. "It's important to establish whether it's a true causal relationship," says Ascherio. He says the question should be urgently addressed by means of a trial that would enrol volunteers and assign them to take the supplement.

MS is a chronic inflammatory disease of the central nervous system that afflicts some two million people worldwide. It is more common among people with northern European ancestry, according to the US National Multiple Sclerosis Society. The illness can be relapsing and remitting or progressive, with symptoms that range from fatigue and slurred speech to tremors, stiffness, poor coordination and in the most severe cases paralysis.

Vitamin D, dubbed the sunshine vitamin because it is naturally produced in skin that is exposed to the Sun's ultraviolet rays, is thought to rein in the overzealous immune system cells that cause the condition.


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