防曬霜或干擾皮膚防禦紫外線

Suncream may actually block the body's natural defence against harmful UV rays, a surprising new study has found.

Scientists from Brown University have discovered that human skin contains sensors that detect radiation from the sun.

These light receptors - which are also found in the retina of the eye - immediately prompt the release of melanin, the body's own form of sun protection.

This is likely to provide rapid protection against UV damage, long before the skin starts to tan.

Researchers now believe that full sunscreen blockage is not necessarily good in sun creams because they block certain wavelengths of light needed to trigger the body's natural defences.

Elena Oancea, lead researcher at the university in Providence, Rhode Island, said: “There was no prior evidence that those receptors can function in skin.”

“Our work shows that a dedicated UV receptor allows skin cells to immediately detect and respond to UV light.”

She added: “This protective capacity should be taken into consideration in the design and use of broad-spectrum sunscreens.”據英國《每日郵報》11月4日報道，一項令人驚奇的新研究發現防曬霜實際上可能會阻礙人體對紫外線的自我防禦。

布朗大學的科學家們發現了在人的皮膚中包含一種感光物質。

在視網膜中也能發現這些感光物質。它們能迅速刺激皮膚黑色素的生成，保護人體不受太陽光線的傷害。

在皮膚開始變黑之前，黑色素就有可能提供最及時的紫外線防護。

研究人員們現在認爲全面防護型的防曬霜未必是好的防曬產品，因爲它們阻擋了某些能夠激發人體自動防禦功能的光波。

普羅維斯登斯(位於羅得島)大學的首席研究員艾琳娜-翁西亞說：“先前沒有證據可以證明這些感光物質能作用於皮膚。”

“我們的研究工作顯示，專門的紫外線感光物質能使皮膚細胞迅速甄別紫外光線並作出反應。”

她補充道：“這種防護能力應當考慮在廣譜防曬霜的研發和使用中加以利用。”