Sun exposure and vitamin D in the childhood protect against multiple sclerosis
It is common knowledge that too much sun exposure can cause skin cancer. On the other hand, lack of sunlight is also a problem. If you expose yourself to plenty of sunlight during your childhood years it lowers your risk of developing multiple sclerosis later in life, according to a study from University of California and Australian National University. The reason why sunlight protects against multiple sclerosis and a number of other illnesses is that the sun is our most important source of vitamin D, a nutrient with multiple functions in the body. Therefore, it is essential to get plenty of sun as long as you avoid getting a sunburn. For people living at northern latitudes, it’s important to follow the official guidelines for vitamin D supplementation to make sure that we have enough vitamin D in our body at all times.
Multiple sclerosis (MS) is an autoimmune disease that can result in considerable disability, even in young people. The disease is characterized by repetitive attacks on the central nervous system (brain and spinal cord) that produce a number of widely different symptoms, depending on what part of the central nervous system is attacked. In 10-15 percent of cases, the symptoms appear gradually without such attacks.
Multiple sclerosis is characterized by inflammation that destroys the protective myelin sheaths that surrounds the neurons, leading to loss of nerve fibers different places in the brain and spinal cord. This eventually affects the nerve transmission.
Multiple sclerosis typically starts at the age of 20-40 years but can even begin in childhood. The condition affects twice as many women and men and it is caused by a combination of genetic and environmental factors. Epstein-Barr-virus (mononucleosis), smoking, and obesity are known to increase the risk. It has also been observed that multiple sclerosis is more common in northern, tempered zones such as Denmark, compared to subtropical and tropical regions. This is because there is more sun in the southern hemisphere and that makes it easier to synthesize vitamin D. This relation is confirmed by the new study.
More sunshine and vitamin D - less risk of developing multiple sclerosis
The study, which is published in Neurology, includes 332 children and teenagers who had had multiple sclerosis for seven months on average. The patients were compared to a group of 534 healthy controls that were matched for age and gender. All participants in both groups were asked to fill out questionnaires (with or without help from their parents) to determine how much sun they had been exposed to the previous summer. It turned out that 19 percent of the MS patients had spent less than 30 minutes daily in the sun, whereas this was only the case with six percent of those without MS.
After the scientists had adjusted for risk factors such as smoking and gender, they found that the participants who had spent 30 minutes or more in the sun every day were 52 percent less likely to develop multiple sclerosis, compared with those who spent less than half an hour daily on average in the sun.
The researchers also observed that people living in sunny Florida had a 21 percent lower risk of getting multiple sclerosis compared with people living in New York. Their general observation was that the more sun youngsters exposed themselves to, the lower the risk they had of getting multiple sclerosis.
The scientists explain that vitamin D helps regulate the immune defense and controls inflammatory processes that are even seen in other types of autoimmune diseases. It is therefore essential for young people to get enough sunshine (without burning) because it helps to reduce their risk of multiple sclerosis. People who don’t get enough sun exposure should take a supplement.
Vitamin D recommendations in Denmark - and the safe upper intake level
The Danish Veterinary and Food Administration recommends that all people take a vitamin D supplement during the winter period. Those who do not get enough sunshine should supplement all year round. All-year supplementation is also recommended for children under the age of four years and vulnerable groups in the population.
The need for vitamin D varies from person to person. A blood sample can easily reveal if you need more. Also, remember that blood levels of vitamin D drop if you don’t take a supplement. Vitamin D can even be overdosed. For that reason, EU’s Scientific Committee on Food has established the following safe daily upper intake levels for vitamin D:
- 25 micrograms for infants (0 to six months of age)
- 50 micrograms for children aged six months to 10 years
- 100 micrograms for children older than 11 years and adults (including pregnant and breastfeeding women)
The safe upper limits do not exceed the amount of vitamin D that the majority of fair-skinned people is able to synthesize in the skin on a sunny summer’s day.
Vitamin D is lipid-soluble. For that reason, it is easiest for the body to absorb and utilize the nutrient if we take it in capsules filled with oil.
Prince Sebastian et al. Association between Time Spent Outdoors and Risk of Multiple Sclerosis. Neurology December 8, 2021
University of California – San Fransisco. Sunshine may shield children, young adults from MS. ScienceDaily December 8, 2021
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