VITAMIN D AND AUTOIMMUNITY

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In recent years vitamin D deficiency has become like an epidemic all over the world. Besides autoimmunity, low vitamin D is associated with many diseases like heart disease, diabetes, cancer, hypothyroidism and many more. In fact, almost every cell in your body has vitamin D receptors.

There are 2 forms of vitamin D3 that you need to keep in mind. The one that is usually tested by most practitioners is Vitamin D3. Your body has to convert Vitamin D3 to the active form 1,25 Dihydroxyvitamin D3[1,25(OH)2 D3]. Most of you are familiar with the action of vitamin D in protecting your bones and maintaining blood calcium levels—the “classical” actions of vitamin However, scientific studies in the last several years have shown that vitamin D has several other actions as well—the “non-classical” actions. These are the actions of vitamin D on bone marrow, immune system, breasts, prostate, heart, muscles and intestine. With respect to autoimmune disease, the immunomodulatory (affecting your immune system) actions of Vitamin D are very important.

Vitamin D has the effect of increasing the activity of the innate immune system while restraining the activity of the adaptive immune system. (Chapter 9). This is the reason why adequate vitamin D3 levels are important for treating and perhaps preventing autoimmune diseases. A substantial number of studies have shown an association between low vitamin D and increased incidence of autoimmune diseases like Rheumatoid Arthritis(RA), Multiple Sclerosis(MS), Psoriasis, Inflammatory Bowel Disease (IBD), Type 1 Diabetes, Sjogrens, Lupus and many more. One example that is often cited is the increasing incidence of MS as one moves away from the equator. This is thought to be related to lesser sun exposure at higher latitudes than at the equator.

1,25 DIHYDROXYVITAMIN D3.

In autoimmune conditions sometimes measuring only vitamin D3 levels may not be enough. A few scientific studies have shown that some people with autoimmune disease have high levels of 1,25 Dihydroxyvitamin D3. This is why sometimes we need to measure both the forms of vitamin D. I remember quite a few occasions when my patients (In India) have called me to say that the lab technician has informed them that “no doctor advises this (1,25 OH)2 D) test” so it is unnecessary!

WHY DO PEOPLE BECOME VITAMIN D DEFICIENT?

Humans obtain vitamin D from either food (fortified), supplements or sunlight exposure. Your blood vitamin D levels depend on several factors.

Air quality: Excessive carbon particles in air from burning of fossil fuels may reduce the amount of vitamin D producing UVB rays from reaching your exposed skin.

Skin color: People with dark skin require about 10 fold more exposure to sunlight to produce the same amount of vitamin D as people with lighter skin color.

How much of your skin is exposed? The more bare skin the bigger the surface area of absorption of sunlight.

Use of sunscreens: Though theoretically use of sun screens can block the UVB rays, rarely do people use adequate quantities of sunscreen to bar all UVB from reaching their skin.

Gut Health: If you have unhealthy gut or you have inflammatory bowel disease (IBD), your absorption of vitamin D from supplements is poor.

Liver and Kidney Health: Some types of liver disease may affect bile production. This can affect vitamin D function. In chronic kidney disease (CKD) the vital step of conversion of vitamin D to its active form is affected and this can lead to severe vitamin D deficiency. This is why patients with CKD have their 1,25 Dihydroxyvitamin D3 measured regularly.

Vitamin D receptor (VDR): If you have a genetic variation in VDR you may need a higher dose of vitamin D supplementation.

How much vitamin D3 you take will decide your blood levels of the vitamin. Very low or very high doses, may both be detrimental unless you monitor regularly.

HOW MUCH VITAMIN D SHOULD YOU TAKE AS A SUPPLEMENT?

How much supplementation of vitamin D you need depends on what your blood reports show. It may not be the same dose for everyone because of individual variations. However, it is a much better idea to take a smaller dose (4000-5000 IU) every day rather than a very high dose once a week or once a month. Sometimes a larger dose may be necessary for a short period of time until your blood levels are in the optimal range.

Ideally you should get your vitamin D from sensible sun exposure AND supplementation.

 WHAT IS MOST IMPORTANT ABOUT VITAMIN D AND AUTOIMMUNE CONDITIONS?

Low vitamin D levels have been associated with many autoimmune conditions like

Rheumatoid Arthritis (RA), Multiple Sclerosis(MS), Psoriasis, Inflammatory Bowel Disease (IBD), Type 1 Diabetes, Sjogrens, Lupus and many more. This is because vitamin D affects your immune system function.

Maintaining adequate vitamin D levels may be a major way to prevent developing autoimmune disease. In fact, studies have shown that maintaining adequate vitamin D levels during childhood can prevent the development of Type 1 Diabetes by 29%! This is true for several other autoimmune conditions as well.

If you already have an autoimmune condition maintaining adequate vitamin D levels will make a major difference to how you heal the disease.

Some of you  may need to measure both vitamin D3 and 1,25 Dihydroxyvitamin D3.