Switching on spring fever
Everyone knows one function of the sun: it lifts your mood. When the gray, dim days of winter are finally over and spring arrives, most people feel fresh and energized.
Researchers at Washington University School of Medicine showed in a 2006 study that there is a link between dampened mood and vitamin D deficiency. A wintertime vitamin D deficiency can even lead to seasonal depression. Vitamin D is also found in foods such as fish. However, the body covers almost 90 percent of its requirements through its own production in the skin – using sunlight (UVB light). Incidentally, just 15 minutes of warm sunlight on the face and arms is enough to enjoy the positive effects. So you don’t have to spend hours in the sun for the body’s cells to boost vitamin D production.
Diabetes due to lack of sunlight
Various studies indicate that too little vitamin D promotes the development of diabetes mellitus. For example, researchers in Finnish children were able to show that taking vitamin D reduced the risk of type 1 diabetes by 80 percent.
People are also less likely to develop type 2 diabetes if they bathe in the sun from time to time. Researchers at the Public Health Institute in Helsinki, which is not exactly sun-drenched, studied 1,400 men and women over a period of 22 years. A particularly clear correlation was found among the participating men: men with too little vitamin D in their blood were 72 percent more likely to develop type 2 diabetes.
However, scientists warn against taking vitamin D supplements lightly. An oversupply can have harmful consequences. So first talk to your doctor about whether it makes sense for you to take vitamin D, and if so, in what dosage.
Sun strengthens the bones
Calcium makes bones strong. But it does not get into the bone tissue easily. It needs a key to do so, and that key is called vitamin D. Sunlight is therefore also important for the strength of the skeleton and thus protects against osteoporosis. This is understood to mean a pathologically reduced bone mass.
In addition, a severe vitamin D deficiency can also lead to softening of the bones (osteomalacia). In childhood, this clinical picture is called rickets. It was particularly widespread in the past – for example, among children of poor people who grew up in dark alleys and were poorly nourished. External signs of rickets include a sunken chest and bent legs.
AIn the area of the central nervous system, vitamin D can prevent aggressive immune cells from attacking the protective myelin layer of the nerve cells (neurons). This is the case, for example, in the autoimmune disease multiple sclerosis (MS). Researchers at the American John Hopkins University were able to show in mice that vitamin D prevents multiple sclerosis. This is consistent with the observation that in countries with plenty of sunlight, fewer people develop MS.
Even in existing MS, the vitamin still has a positive effect: it slows the progression of the disease.
Radiant blood pressure reducer
Vitamin D against cancer
People who have a lot of vitamin D in their blood are less likely to develop colorectal cancer. This was the result of a metastudy involving 520,000 people. The group of subjects with the highest vitamin level even showed a 40 percent lower cancer risk than the participants with the lowest value.
A high vitamin D level also helps people with skin cancer: the cancer is usually less serious and less likely to be fatal.
Turbo for the immune system
Vitamin D activates the immune system, or more precisely the T cells. These are a special type of lymphocytes. When T cells detect an intruder in the body, they extend a kind of antenna. It is equipped with a receptor that searches for vitamin D. Only when the sunshine vitamin is present do the T cells transform from harmless immune cells into active killer cells that eliminate bacteria or viruses, for example. If vitamin D is missing, on the other hand, the cells remain inactive.
Skin cancer paradox
Scientists suspect that the skin loses its ability to build up natural sun protection if it is not sufficiently accustomed to the sun. This is because with sufficient sun exposure, a fine thickening of the cornea, the so-called light callus, forms in addition to the protective dark skin coloration. However, if you are rarely in the sun and then suddenly expose yourself to it to a high degree (e.g. during extensive sunbathing on Mediterranean beaches), you will quickly get a sunburn. And this in turn increases the risk of skin cancer. The study result is therefore by no means a carte blanche for careless exposure to the sun!
