Sclerosis, rheumatoid arthritis, certain gastrointestinal infections, and a host of other diseases are so-called autoimmune diseases that occur as a result of the immune defense overreacting and attacking the body’s own tissues. Scientists from the University of Edinburgh in Scotland have now mapped out exactly how vitamin D regulates the immune system. In fact, vitamin D may have a positive effect on autoimmune diseases such as sclerosis. But at our latitude, this provides that we get enough vitamin D from the sun in the summertime and take vitamin D supplements in the winter period. Besides, it is a problem that being overweight both increases the risk of vitamin D deficiency and sclerosis, while lack of magnesium makes it difficult for the body to activate vitamin D.
It is hardly a surprise that sclerosis is a lot more common at northern latitudes: The main reason why we lack vitamin D in this part of the world is that we are only able to produce vitamin D during the summer period, where the sun sits sufficiently high in the sky. Too much indoor activity only adds to the risk. It is commonly known that vitamin D is essential for bone health, but we must not forget that all our cells have vitamin D receptors and the nutrient controls a host of genes and biochemical processes. Therefore, although the official recommendations – or RI (reference intake) level – may be able to prevent bone loss (osteoporosis), it appears that our need for vitamin D is a lot greater, if we aim at preventing different diseases, including the autoimmune diseases.
Vitamin D affects the dendrite cells and T cells of the immune defense
Scientists at the University of Edinburgh focused on how vitamin D affects the body’s immune system – more specifically the dendrite cells. These are specialized white blood cells that are located on the skin and the inner surfaces of the nose, lungs, stomach, and intestines. Dendrite cells are the outposts of the immune defense and present antigens from bacteria and other foreign compounds to the immune system’s T cells, which are the special troops.
T cells also play a major role in fighting infections in healthy individuals. However, T cells are particularly aggressive white blood cells that should be kept on a tight leash. In people with sclerosis and other autoimmune diseases, T cells overreact, resulting in chronic inflammation and tissue damage.
Vitamin D hampers the overactive immune defense in autoimmune diseases
By studying white blood cells from mice and humans, scientists have found that vitamin D steps up the production of the molecule CD31 in the surface of the dendrite cells. CD31 is the molecule that inhibits or controls the activation of T cells. The researchers specifically saw how CD31 prevented the two cell types from staying in contact, and this helps slow down the overactive immune defense.
According to the researchers, this discovery sheds new light on how vitamin D controls the immune defense. Based on their observations, vitamin D has a positive influence in prevention and as part of the treatment of autoimmune diseases such as sclerosis. Still, it requires that we get enough vitamin D on a daily basis, and it also requires that the body is able to activate the vitamin.
Their research is published in the science journal Frontiers of Immunology.
Vitamin D deficiency and overweight increase the risk of sclerosis – especially in children
The risk of contracting sclerosis is increased by overweight, and children are particularly vulnerable, according to an earlier study published in the science journal Neurology. One should therefore focus more on weight management for preventing sclerosis and make sure to get plenty of vitamin D at all times. At the same time, sun awareness campaigns that warn against sun exposure and recommend the use of sunscreen should provide children and adults with guidelines for getting enough vitamin D from other sources.
Did you know that overweight increases your need for vitamin D?
Official recommendations for vitamin D and our actual need
The reference intake (RI) level for vitamin D (in Denmark) is 10 micrograms, but many scientists believe that the actual need for vitamin D is substantially higher, and their recommendations lie in the range between 30 and 100 micrograms daily. This is an amount, which one can easily synthesize on a sunny summer’s day. However, the production of vitamin D is lower in dark-skinned people or individuals with thin and old skin. In addition, overweight individuals and diabetics have difficulty with producing and utilizing the vitamin.
During the winter period, we all need to take a supplement because the diet only provides limited quantities of the nutrient. Vitamin D is a lipid-soluble vitamin and is therefore absorbed and utilized best in an oil-based formula in capsules.
Our ability to utilize vitamin D depends on our age and magnesium status
As mentioned, vitamin D is synthesized in the skin when we expose ourselves to sunlight. What we humans produce, however, is a precursor of vitamin D called cholecalciferol (which is also available in supplement form). The ability to process and utilize the vitamin from that point on hinges on several factors. First, vitamin D must be converted into 25-hydroxyvitamin D3 in the liver. This is the form of the vitamin that is measured in the blood. Next, it is converted into an active form in the kidneys. The different enzyme processes needed for the vitamin conversion require the presence magnesium.
Lack of magnesium can also make it difficult for the body to utilize vitamin D from the sun or from supplements. In other words, if you have too little magnesium, you may have too little active vitamin D in your blood, even if you get plenty of sunlight.
Louise Saul et al. 1,25-Dihydroxyvitamin D3 Restrains CD4 T Cell Priming Ability of CD11c Dendritic Cells by Upregulations Expression of CD31. Frontiers of immunology.
University of Edinburgh. Vitamin D study sheds light on immune system effects. ScienceDaily. 2019
Magdalena Kegel. Obesity and Poor Vitamin D Levels Tied to Risk of Childhood MS in Study. 2017
Gerry K. Schwalfenberg and Stephen J. Genuis. The Importance of Magnesium in Clinical Healthcare. Scientifica (Carro) 2017
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