Researchers at Lund University have discovered how the skin shields us against the harmful ultraviolet rays of the sun.
The study team examined skin pigment and its building blocks and found that the pigment protects the body from harmful ultraviolet rays by converting these radiations into heat through a rapid chemical reaction that releases protons from the molecules of the pigment.
The findings can help in better treatment against skin cancer.
Researchers explained that pigment in both the skin and hair constitute two different types of melanin: eumelanin and pheomelanin. Eumelanin helps develop a suntan and gives color to brown and black hair while people with red hair and pale skin have high levels of pheomelanin.
For long eumelanin is known for its shielding properties against UV radiation while pheomelanin is known to cause skin cancer in some way. This explains why people with red hair are prone to develop malignant melanoma.
"We found that eumelanin converts harmful UV radiation into heat with almost 100 per cent efficiency. The chemical reaction is incredibly quick, taking less than a thousandth of a billionth of a second," said Villy Sundstrom, Professor of Chemistry at Lund University.
According to the researchers, a hydrogen ion - proton - is released from the pigment at the same time as the UV light reaches the pigment molecule. The chain of events is similar to the melanin getting rid of the energy of the UV light by very quickly shooting a proton.
This proton projectile in turn gives off energy to the surrounding membrane tissue in the form of heat. It converts dangerous UV energy into harmless heat. "In this way, the pigment disarms the energy in the UV light and prevents it causing harmful chemical reactions," said Sundstrom.
"By understanding how the body naturally protects itself against UV light, we can develop better sun protection products based on the same principles. This would provide better protection against skin cancer," said Sundstrom.