The connection between vitamin D and multiple sclerosis (MS) has to do with sunshine and the proper functioning of the immune system. The sunshine connection comes from studies that have shown a high rate of MS in regions with minimal sunlight and the fact that vitamin D comes from the sun. The immune system connection stems from the effects of vitamin D deficiency on the body's immune responses and MS being an autoimmune disease.
Simple geography led to one of the most common connections between vitamin D and multiple sclerosis. Several circumstances can lead to vitamin D deficiency, but the most common is a lack of proper sun exposure. One study found that people who live far from the equator during childhood have a higher rate of MS than those who grow up closer to the equator. Scientists theorized that low levels of vitamin D caused by diminished sunshine exposure might be responsible for the high instances of MS in the northern hemisphere. Subsequent research found that supplementation with vitamin D3 completely wiped out the development of MS in lab mice.
Another study connecting vitamin D and multiple sclerosis discovered that babies born during the spring are more likely to develop MS later in life. Research has shown that vitamin D levels are lowest during the spring. This might be because there is less sunlight during the fall and winter months. The correlation is that babies whose mothers have low levels of vitamin D are at greater risk for MS.
In another link between vitamin D and multiple sclerosis, research has shown that vitamin D deficiency leads to poor immune system function. Multiple sclerosis is an autoimmune illness in which an impaired immune system attacks and damages the brain and spinal cord. Some researchers believe that preventing vitamin D deficiency with sun exposure or vitamin D supplements can reduce the risk of acquiring MS.
There also is a connection between vitamin D and multiple sclerosis in the areas of treatment and prevention. Research has shown that vitamin D supplements for MS treatment reduced lesion damage on the spinal cord when taken in dosages of up to 10,000 international units (IU) daily. Patients undergoing this treatment also had fewer symptom flare-ups.
Vitamin D also might help in the area of MS prevention. One study showed that women who took at least 400 IU of vitamin D daily lowered their chances for developing MS. In the absence of regular sun exposure, research suggests that one of the benefits of vitamin D supplements, including those found in multivitamins, might be reduction in the chances of MS developing, even in people who are genetically predisposed to contracting the disease.