Nutrition

Are tanning beds a safe source of vitamin D?

Sensible sun exposure provides the body with the vitamin D that it needs to help ward off depression, heart disease, stroke, cancer, and osteoporosis. However, many people have trouble incorporating sunshine into their daily routines, especially in winter months when daylight hours are few and outdoor activities scarce. When sunshine is hard to come by, it might be tempting to substitute a trip to the tanning salon for time spent outdoors. Can tanning beds offer the same health benefits as sunshine? Specifically, are tanning booths a safe source of vitamin D? Tanning salons might like you to think so, but don’t be fooled. Indoor tanning is not an advisable source of vitamin D. The reason lies in the characteristics of ultraviolet light rays, and how these rays affect the body.

Both the sun and tanning beds emit two types of ultraviolet light rays, UVA and UVB. The skin absorbs both types, but in different ways. UVA rays have longer wavelengths that penetrate into the deepest layers of the skin, whereas UVB rays’ wavelengths are short and only reach the surface layers of skin. Both types of rays contribute to the health risks associated with excessive sun exposure, such as the risk of developing skin cancers. However, UVB rays also trigger the synthesis of the vitamin D precursor in the skin, and thus are solely responsible for the healthy benefits of sunshine. For most people, exposing one’s arms and face to sunshine for about 20 minutes per day provides the skin with enough UVB rays to eliminate vitamin D deficiencies, without causing long-term damage to the skin.

However, while UVB rays account for the health benefits of sunshine, tanning salons are more interested in UVA rays. This is because overexposure to UVB rays, which affect the surface layers of skin, quickly causes sunburns. On the other hand, UVA rays are responsible for the golden-brown tan sought after by most salon patrons. As a result, most tanning salons calibrate their tanning beds to emit approximately 95 percent UVA rays. This calibration maximizes the tanning effects of the machine and minimizes the risk of burning. Unfortunately, it also minimizes the amount of vitamin D that can be metabolized relative to the exposure to damaging ultraviolet rays.

In theory, a tanning bed can be calibrated to emit a greater percentage of UVB rays. However, it is important to remember that the safety of exposure to either type of ultraviolet rays depends upon its moderation. Most people do not enter tanning beds wearing pants and T-shirts, and exposing too much surface area of the skin can quickly result in excessive absorption of ultraviolet light rays.

That something as simple as being in the sun can have such profound effects on our health is exciting news, but do not disregard the risks of overexposure. Remember, 15–20 minutes of sunshine a day, several times per week, provides sufficient UVB absorption for most Caucasians to optimize their vitamin D levels; however, the darker your skin, the more time you need. In addition, this natural mechanism does not work equally well at all latitudes and seasons and in all people. If you are unsure of the amount of sunshine needed, you can get your vitamin D levels tested and consider supplementing your vitamin D3 intake. Most tanning beds, while they might offer a golden-brown hue, put you at risk of unnecessary, excessive exposure to dangerous UVA rays, and are by no means a substitute for old-fashioned sunshine.

Related to this article:

Is vitamin D deficiency casting a cloud over your health?
Vitamin D testing and treatment guidelines

 

Last Modified Date: 04/20/2011