What Are The Benefits Of Vitamin D For Autoimmune Diseases?

The phrase "autoimmune disease" encompasses a wide array of conditions, including rheumatoid and psoriatic arthritis, lupus, inflammatory bowel diseases, Sjögren's syndrome, Hashimoto's thyroiditis, Grave's disease, pernicious anemia, scleroderma, Type 1 diabetes and other disorders. The common thread in all autoimmune disorders is the presence of antibodies made by your immune cells, which attack your own tissues, leading to inflammation and tissue damage. Environmental, infectious, genetic and nutritional factors have been implicated as possible triggers for autoimmune diseases.

Vitamin D

Vitamin D, or calciferol, is a fat-soluble vitamin found in egg yolks, butter, liver, oily fish and fortified dairy products. Your skin synthesizes cholecalciferol, or vitamin D3, when you are exposed to ultraviolet light. According to "The Merck Manual of Diagnosis and Therapy," vitamin D3 is the form that becomes biologically active in your body through a series of conversions in your liver and kidneys. Vitamin D performs more like a hormone than a traditional vitamin in your tissues, in that many of its effects are mediated by its interactions with receptors on your cells. Maintaining adequate vitamin D levels may help to prevent autoimmune diseases.

Receptors

According to a January 2011 "Experimental Dermatology" review, vitamin D receptors, or VDRs, have been identified on nearly all human cells, including immune cells. The specific functions of VDRs in many of your tissues have not been fully defined, but some scientists believe they regulate the movement of calcium into your cells, a basic function that is essential for their proper function. The presence of VDRs on immune cells implies a role for vitamin D in the normal immune response, but vitamin D supplementation may not lessen the symptoms of autoimmune conditions.

Vitamin D and Autoimmunity

A 2011 article published in "Vitamins and Hormones" cites the epidemiologic evidence linking vitamin D deficiency to autoimmune diseases. Lower blood levels of vitamin D have been documented in individuals with systemic lupus erythematosus, Type 1 diabetes, undifferentiated connective tissue disease -- also known as mixed connective tissue disease -- and rheumatoid arthritis. The review's authors suggest that novel treatments for these and other autoimmune diseases could exploit the relationship between vitamin D and VDRs on immune cells. However, it is not clear if vitamin D supplementation is useful for treating autoimmune diseases.

Considerations

There is controversy surrounding the optimal vitamin D doses needed to support your bones, immune system and other organ systems. The Food and Nutrition Board of the American Institute of Medicine has set a tolerable upper limit for vitamin D at 2,000 IU daily. However, some experts, such as Dr. Reinhold Vieth of Mount Sinai Hospital in Toronto, believe the upper limit should be increased to at least 10,000 IU daily.

Recommendation

Current vitamin D recommendations for patients with autoimmune disorders are the same as those for healthy individuals, unless you have had a blood test which shows that you are vitamin D deficient. Daily requirements for healthy people are based on age: for children and adults to age 50, 200 IU; for adults aged 50 to 70, 400 IU; for adults over age 70, 600 IU. Ask your doctor if you need additional vitamin D.