Vitamin D inhibits inflammation
- which is involved in asthma, rheumatoid arthritis and most chronic diseases
This time of year, many people suffer from asthma, aching joints, or an exacerbation of other chronic diseases that involve inflammation. This is often because they lack vitamin D, as the sun sits too low in the sky for us humans to be able to synthesize the vitamin. Also, the diet and normal vitamin pills only provide minimal amounts vitamin D. It has been known for a long time that vitamin D counteracts inflammation. Now, a large systematic study is planned to investigate how supplementing with large quantities of vitamin D can affect the molecular mechanisms that counteract inflammation.
The summer sun is our primary source of vitamin D at this latitude. Lack of vitamin D is a growing problem that affects millions of people all over the world – all year round – because of factors like too much time spent indoors and exaggerated use of sun factor cream to prevent skin cancer. Vitamin D is primarily known for its role in bone health, but vitamin D actual influences most cells in the body. Now, researchers are showing increasing interest in the molecular mechanisms involved in several chronic inflammatory conditions such as rheumatoid arthritis, Crohn’s disease (inflamed intestine), thyroid disorders (Hashimoto’s and Graves disease), multiple sclerosis, insulin resistance, type-2 diabetes, obesity, cardiovascular ailments, and cancer.
The more vitamin D, the less inflammation
Researchers from National Jewish Health in Denver, the United States, discovered earlier how vitamin D affects the immune system and inhibits inflammatory processes by means of molecular mechanisms. It is vital that the white blood cells of the immune system are able to fight infection and repair cellular damage. However, it is also important that the immune defense does not overreact, because chronic inflammation may cause local symptoms and tissue damage.
In addition, chronic inflammation bombards the body with free radicals that are extremely harmful.
In their in-vitro study, the researchers supplied white blood cells with different levels of vitamin D from solutions that corresponded with vitamin D blood levels of 0-50 ng/ml. Afterwards, the white blood cells were exposed to a molecule called LPS (lipopolysaccharide) that is attached to the cell wall of bacteria and normally trigger an intense inflammatory reaction.
The white blood cells that had not been given any vitamin D or just a solution that was the equivalent of having 15 ng/ml of vitamin D in the blood, produced high levels of cytokines, IL-6 and TNF-alpha, which are the key players involved in inflammation. The white blood cells that were given a solution that corresponded to 30-50 ng/ml of vitamin D in the blood showed a significantly lower response to LPS, and the response was the lowest in those white blood cells that had been given the most vitamin D.
In a series of experiments the researchers identified new sites where the cells’ vitamin D receptors (VDR) react directly with cellular DNA and activate a gene (MKP-1) that shuts down undesirable inflammatory processes. The study showed that vitamin D’s ability to inhibit inflammation depends on blood levels of the vitamin, and the best results are seen when levels are above 50 ng/ml.
Global vitamin D deficiency
The optimal level of vitamin D in the blood, according to official recommendations, is when it is above 50 ng/ml. It is therefore worrying that 20-60% of the British population lacks vitamin D, and that vitamin D deficiencies are also widespread in the United States and Europe. Despite their sunny climate, 50% of Australian women and 31% of Australian men lack vitamin D.
The new systematic study
Professor Barbora de Courteen and her team of researchers plan on conducting a larger systematic study to demonstrate how vitamin D supplements inhibit inflammation in a large group of people. The reason why they want to investigate this is that vitamin D deficiencies have become a global problem of epidemic proportions, but it is also because lack of vitamin D is involved in an array of different diseases that impair quality of life and cost millions of lost lives.
Several human and animal studies have shown that vitamin D inhibits inflammation. However, the studies are often limited to individual population groups such as children or people with specific inflammatory diseases in their joints, airways, or digestive systems. We still need to find out what effect supplements of vitamin D have on inflammation in larger groups, and this is what the new study intends to clarify. Also, the study will show the effect of vitamin D supplementation in the treatment of inflammation compared with placebo and regular medical therapy, and it will show how vitamin D compares with other medical and non-medical therapies.
Why vitamin D is so important for the immune system
Vitamin D is synthesized from cholesterol and functions as a steroid hormone in the body. Most cells have vitamin D receptors (VDR). The white blood cells of the immune system have particularly many vitamin D receptors, including dendrite cells, macrophages, and T and B lymphocytes.
First of all, vitamin D is able to activate the different types of white blood cells in the immune system, which is vital for the body’s ability to prevent and fight infection. Secondly, vitamin D prevents the immune system from causing havoc by regulating and limiting the release of different cytokines from white cells. Cytokines are chemical messengers that initiate inflammatory response.
|If we lack vitamin D, it increases our risk of infections and undesirable inflammation, both of which are characteristic of most chronic ailments.|
Aya Mousa et al. Effect of vitamin D supplementation on inflammation: protocol for a systematic review. BMJ Open 2016
National Jewish Health. How vitamin D inhibits inflammation. ScienceDaily 2012
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