It is no coincidence that sclerosis is more prevalent at the northern latitudes. A major factor is lack of vitamin D, a nutrient that we only synthesize from sunlight during the summer. A new study published in the scientific journal Neurology shows that the risk increases even more if people are overweight, and children are particularly vulnerable. As part of the strategy for preventing sclerosis, we must pay more attention to weight management and make sure to get plenty of vitamin D all year round and throughout life. Furthermore, various campaigns that warn against sun exposure and recommend the use of sunscreen should at the same time advise children and adults how to get enough vitamin D from other sources.
Sclerosis – also called multiple sclerosis (MS) or disseminated sclerosis – is a chronic, progressive, autoimmune disease. The reason why sclerosis is so disabling is that the immune system attacks the protective myelin sheaths that surround the axons of the nerve cells. Sclerosis is characterized by repetitive attacks from different parts of the central nervous system, and symptoms can vary tremendously. Some people have very few problems, while others are incapacitated by leg paralysis, involuntary urination, speech difficulty, and possibly even dementia.
New knowledge: Overweight, vitamin D-deficient children are more exposed
According to a new study of 569 children with sclerosis and 16,251 healthy controls, the sclerosis sufferers were even more likely to have developed their disease if they were overweight and lacked vitamin D. We already know that overweight and lack of vitamin D increases the risk of sclerosis in adulthood, but it is new to science that children are more exposed.
The study, which is published in the scientific journal Neurology, was conducted by scientists from the University of California, San Francisco and Berkeley, and involved children from the United States and Sweden.
The researchers developed what they called a genetic risk score, which enabled them to analyze how overweight and lack of vitamin D influenced the risk of developing sclerosis. The score for vitamin D was based on the presence or absence of three genetic variations that affect blood levels of vitamin D. The score for overweight was based on 97 variations. The researchers also took other factors into account such as sex and hereditary factors.
The study is not the first to reveal a link between overweight, lack of vitamin D, and sclerosis. The researchers have already pointed out that overweight alone may result in a vitamin D deficiency that increases the risk of sclerosis. However, according to their new study, both overweight and lack of vitamin D have an independent effect on the disease risk. Their study even showed how hereditary and environmental factors can interact and increase the risk of getting sclerosis. Nonetheless, vitamin D plays a key role in regulating the immune system. The question is: What happens in the brain?
Sclerosis causes misinformation of the immune defense
The immune defense, our main source of protection against infections, consists of different white blood cells that are referred to as T and B lymphocytes. When sclerosis develops, the T lymphocytes, which under normal circumstances target and attack microbes aggressively, are misinformed by the body’s lymph nodes. When the T lymphocytes are dispatched in the bloodstream, they find and destroy the myelin sheaths of the nerve cells. Depending on which nerve cells that are destroyed, this may lead to blurry vision, chronic fatigue, muscle weakness, numbness, and other sclerosis symptoms.
Vitamin D regulates the T lymphocytes
Researchers from Johns Hopkins University School of Medicine assume that vitamin D works by preventing T lymphocytes from entering the brain. In studies where mice with sclerosis have been supplemented with large doses of vitamin D, researchers have found a large number of T lymphocytes in the blood of the affected mice, while only few T lymphocytes are present in their brains and spinal cord.
In contrast, scientists have observed that there are very low concentrations of vitamin D in the blood of humans with sclerosis, which is associated with an increased disease activity and disabilities.
How much vitamin D do we need?
The dietary reference intake level (RI) for vitamin D for adults is 10 micrograms, but many researchers believe that the actual need for vitamin D is much higher. They recommend between 30 to 100 micrograms per day. It is easy to produce that amount on a nice sunny day during summer, but in the winter period, we need to take a supplement, as a normal healthy diet only provides limited amounts of the nutrient. It is also important to remember that sunscreen with a sun factor higher than 8 blocks vitamin D synthesis in the skin. A good way to avoid this problem is to get 20-30 minutes of unprotected sun exposure before applying sunscreen, so the skin is able to produce enough vitamin D.
Vitamin D, supplements, and absorption
Vitamin D is a lipid-soluble nutrient. We utilize it best by taking capsules with vitamin D that is dissolved in some kind of vegetable oil. Daily supplementation with vitamin D in the range of 30-80 micrograms is considered to be safe.
Other causes and possible connections
Two to three times more women than men are affected by sclerosis, so hormone imbalances appear to increase the risk. Smoking alone increases the risk of getting sclerosis by 40-80 percent. Virus, environmental toxins like mercury, and certain types of tissue types may also increase the risk. It is very likely that certain infections and poisonings burden the immune defense, causing it to overreact more easily and attack the myelin sheaths, especially if vitamin D is lacking at the same time.
Magdalena Kegel. Obesity and Poor Vitamin D Levels Tied to Risk of Childhood MS in Study. 2017
Milena A et al. Evidence for causal relationship between low vitamin D, high BMI and pediatric – onset Ms. Neurology 2017
Sotirchos et al. Safety and immunologic effects of high- vs low-dose cholecalciferol in multiple sclerosis. Neurology 2016
Alberto Ascherio et al. Vitamin D as an Early Predictor of Multiple Sclerosis Activity and progression. Jama Neurology 2014
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