防晒霜或干扰皮肤防御紫外线

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.”据英国《每日邮报》11月4日报道，一项令人惊奇的新研究发现防晒霜实际上可能会阻碍人体对紫外线的自我防御。

布朗大学的科学家们发现了在人的皮肤中包含一种感光物质。

在视网膜中也能发现这些感光物质。它们能迅速刺激皮肤黑色素的生成，保护人体不受太阳光线的伤害。

在皮肤开始变黑之前，黑色素就有可能提供最及时的紫外线防护。

研究人员们现在认为全面防护型的防晒霜未必是好的防晒产品，因为它们阻挡了某些能够激发人体自动防御功能的光波。

普罗维斯登斯(位于罗得岛)大学的首席研究员艾琳娜-翁西亚说：“先前没有证据可以证明这些感光物质能作用于皮肤。”

“我们的研究工作显示，专门的紫外线感光物质能使皮肤细胞迅速甄别紫外光线并作出反应。”

她补充道：“这种防护能力应当考虑在广谱防晒霜的研发和使用中加以利用。”