UVB for optimal vitamin D levels

The most important source of vitamin D is sunlight. When sunlight hits the skin, the skin produces vitamin D. That is why vitamin D levels are at their highest at the end of summer. According to the study we just mentioned, the average Dutch person has a vitamin D level of only 60 nanomoles/L during the summer months, when vitamin D levels should be at their highest. That is 15 points below the level that specialists consider optimal.

This fact alone is cause for concern. Vitamin D is crucial for strong bones and muscles, healthy blood vessels, an adequate immune system and many other aspects of health. If vitamin D levels do not reach the desired level in summer, what about in winter?

Well, according to the 2015 study, vitamin D levels drop in winter. The average Dutch person has a vitamin D level of around 45 nanomoles/L in winter. That is 30 points below the optimal level.

Fortunately, that average level is still above 30 nanomoles/L. If vitamin D levels fall below that level, doctors sound the alarm. With vitamin D levels below 30 nanomoles/L, the amount of vitamin D in the body is so low that health can be immediately endangered. From a medical point of view, a vitamin D level of 45 nanomoles/L is certainly something that needs to be corrected, but it is not an emergency.

We should note right away that we are talking about averages here. If we look at the figures more closely, 30 percent of Dutch people have vitamin D levels below 30 nanomoles/L in winter. That is almost 1 in 3 Dutch people.

In summer, the situation is slightly less alarming, but even then, 12 percent of Dutch people still have vitamin D levels below the critical threshold of 30 nanomoles/L.

The best way to increase vitamin D levels is to move to a country where the sun always shines and life takes place outdoors all year round. For most of us, that is not an option. For this reason, the Dutch Nutrition Centre advises large groups of Dutch people to take pills with extra vitamin D. However, not everyone feels comfortable with this advice, even though the logic behind it is indisputable.

An alternative to pills is the use of UVB technology: lamps that emit a mild and safe form of artificial sunlight, allowing the skin to produce vitamin D3 naturally. The effectiveness of UVB technology is demonstrated by a study published by researchers at Amsterdam UMC in 2014 in Photodermatology, Photoimmunology & Photomedicine.

Just before the experiment began, summer had just ended. The researchers saw this reflected in the blood of the test subjects. They had relatively high levels of vitamin D in their blood: 73 nanomoles/L. This is significantly more than the average Dutch person has in their blood after the summer, but still not quite the optimal level as determined by the Endocrine Society.

The researchers divided their test subjects into two groups. One group did not receive any treatment with UVB light. This was the control group. Over a period of four months, the vitamin D level in this group dropped by 15 points to 58 nanomoles/L. This was to be expected.

The test subjects in the other group stood in front of a Dermasun Helios for 7 minutes almost every day while showering. Their skin therefore received a mild amount of artificial sunlight every day, and the researchers also saw this reflected in the test subjects' blood. After four months, their vitamin D levels had risen to 93 nanomoles/L. This is well within the optimal range.