Sun Tanning May Lower Necessary Vitamin D Levels In The Body

Sunlight is supposed to be good for producing Vitamin D by the skin, however it seems there can be too much of a good thing. According to a recent research, excessive exposure to sunlight can lower the body's ability to produce the vital nutrient.

Researchers in Brazil found that though tanned skin provides coverage against harmful UV rays of the sun, the increase in pigmentation interferes with Vitamin D synthesis in the body, leading to its decrease. "Our findings suggest that skin tanning, which is a natural protection against the harmful effects of UV irradiation, limits the progressive rise in serum vitamin D towards optimal concentrations," said study author Dr. Francisco Bandeira.

The research involved nearly 1,000 males and females in the 13 to 82 years age group, all of whom had a significant amount of daily exposure to sunlight, but do not take Vitamin D supplements or use sunscreen regularly. Researchers examined the response of the different skin types to UV light with the Fitzpatrick skin phototype scale, used by dermatologists to find out the numerical measure of skin type and color.

A higher score on the scale denotes darker skin hues and their tendency to tan.  In addition, the number of hours spent under the sun on a weekly basis was also taken into account to calculate the volunteers' sun index.

After comparing the participants' skin types and sun index scores with the levels of Vitamin D in their blood, it was found out that those who had higher exposure to sunlight had lower levels of the nutrient. Furthermore, the research found that 72 percent of the volunteers had Vitamin D deficiency, in particular those who belonged to older age brackets and had lower sun index rates. The results of the study were presented at the annual Endocrine Society meet in Boston.