A little more sunshine might help you live longer, according to a study suggesting that for some people health benefits from the sun outweigh the risk of skin cancer.

Sunlight spurs the body to produce vitamin D but fear of skin cancer is keeping many people in the shade and depriving them of an important protection from a range of diseases, researchers said.

"The skin cancer risk is there but the health benefits from some sun exposure is far larger than the risk," said Johan Moan, a researcher at the Institute for Cancer Research in Oslo, who led the study. "What we find is modest sun exposure gives enormous vitamin D benefits."

A number of studies have found protective effects from higher vitamin D intake for some cancers and ailments such as rickets, osteoporosis and diabetes, Moan said. Certain foods contain vitamin D but the body's main source comes from the sun.

The researchers calculated that given the same amount of time spent outside, people living just below the equator in Australia produced 3.4 times more vitamin D than people in Britain and 4.8 times more than Scandinavians.

This means even though rates of internal cancers such as colon cancer, lung cancer, breast cancer and prostate cancer rise from north to south, people in the sunnier latitudes were less likely to die from the diseases, the researchers said.

"The current data provide a further indication of the beneficial role of sun-induced vitamin D for cancer prognosis," said Richard Setlow of the US Department of Energy's Brookhaven National Laboratory, who worked on the study.

Getting more vitamin D – which helps the body's immune system work properly – is also critical for people living in places like Scandinavia where long winters and short days during the year limit sun exposure, Moan added.

In Norway, Moan estimated that doubling the sun exposure for the general population would also double the number of annual skin cancer deaths to about 300 but that 3,000 fewer people would die from other cancers.

"The benefits could be significant for people in other countries as well," he said in a telephone interview. "I would be surprised if they were different."

Moan, whose findings were published in the Proceedings of the National Academy of Sciences, recommended daily sun exposure for about half the time it takes a person to get sunburn.

Another way to get more vitamin D could be designing sunscreen that blocks long ultraviolet wavelengths that trigger the deadliest forms of skin cancer while letting through short ultraviolet wavelengths that produce the vitamin, the researchers said.

多晒太阳可以帮助你活更长时间，根据一项研究表明，一些人从日照得到的好处胜于得皮肤癌的危险。

研究人员说，阳光能促使身体产生维他命D,但是恐惧得皮肤癌使许多人躲在黑暗里，这种恐惧剥夺了一系列疾病的重要保护。

"得皮肤癌的危险是存在的，但是从日照得到的益处远远大于得癌的危险"奥斯陆癌症研究中心的研究员Johan Moan说"我们发现适当日照产生大量维他命D"

Moan 说，大量研究发现服用高浓度的维他命D对某些癌症和疾病有保护效果，如软骨病，骨质疏松及糖尿病。 某些食物也含维他命D但人体所需维他命D主要来自日照。

研究人员计算出同等时间户外活动的情况下，生活在赤道的澳大利的人产生的维他命D是英国人的3.4倍，斯堪的纳维亚人的4.8倍。

研究人员说，这就意味着即使得体内癌症如结肠癌肺癌乳腺癌及前列腺癌的几率从北向南上升，生活在日照多的地区的人死于这些疾病的可能性小的多。

当前数据阳光产生维他命D为癌症预测提供了进一步的征象。进行这项研究的美国能源部Brookhaven国家实验室的 Richard Setlow 说。

Moan补充道，获得更多的维他命D有益于身体免疫系统适当工作，同时对生活在像斯堪的纳维亚那样冬天长白天短一年日照有限的地方来说是至关重要的。

在norway,moan估计双倍晒太阳的人得皮肤癌的几率也是双倍，大约有300人，但是死于得其他癌症的要少3000.

晒太阳的益处对其他国家的人们同样重要。moan在电话采访中谈到。"如果他们有什么不同我将很惊奇"

moan,他的研究成功发表在国家科学的公报上，他指出每天晒半天太阳容易晒伤。

研究人员说，另一种获得维他命D方法可能为设计一种防晒霜，她阻挡致癌的长波紫外线，但能获得产生维他命D的短波紫外线。