As the skin becomes darker, it protects itself from harmful ultraviolet rays. Skin tanning, however, may affect the skin's ability to produce Vitamin D, which is vital in calcium absorption and bone growth.
A team of researchers from the University of Pernambuco Medical School in Brazil found that too much sun exposure could boost pigmentation which blocks vitamin D synthesis and affects the skin's ability to produce more Vitamin D.
In the study presented during ENDO 2016 in Boston, the annual meeting of the Endocrine Society, researchers showed that people living in a tropical region, where most of them are exposed to the sun, had vitamin D levels below the normal (30 nanograms per milliliter).
The study involved nearly 1,000 people between the ages of 13 and 82 years old. All of the participants had high rates of sun exposure since they live in a warm place and they do not use sunscreen for protection or take vitamin D supplements. By assessing each person's skin through the Fitzpatrick skin phototype scale, they will be able to determine the sun index, which is equivalent to the number of hours of exposure to the sun in a week multiplied by the fraction of body surface area exposed.
After measuring the vitamin D levels in the blood of the participants, the researchers compared these with the skin phototype and sun index scores.
As a result, they found that 72 percent of the participants had lower levels of Vitamin D. Their average vitamin D level was only 26.06 ng/ml, which is lower than the recommended normal level.
"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 Dr. Francisco Bandeira, chief of the Division of Endocrinology and Diabetes at the University of Pernambuco.
Vitamin D deficiency has been linked to a wide array of health problems including certain cancers of the breast, colon and prostate. It's also linked to heart disease, weight gain, depression and other illnesses. The most common benefit of vitamin D in the body is its ability to absorb calcium and promote bone health. In some people with lower vitamin D levels, they may suffer from bone health problems like rickets (soft bones) in children and osteomalacia in adults.
Photo: Eve Erin | Flickr
