防晒霜会导致维生素D缺乏吗?答案是肯定的

防晒霜会导致维生素D缺乏吗?答案是肯定的

Exposing skin to sunlight is a convenient way to meet our vitamin D needs, which is crucial for bone health. That might make you wonder: Does wearing sunscreen interfere with vitamin D levels and potentially cause vitamin D deficiency?

将皮肤暴露在阳光下是满足我们对维生素D的需求的一种方便的方式，这对骨骼健康至关重要。这可能会让你怀疑:涂防晒霜会干扰维生素D的水平，并可能导致维生素D缺乏吗?

The answer is yes. But before you toss your SPF 30, dermatologists say the relationship between sunscreen and vitamin D is much more nuanced than that.

答案是肯定的。但皮肤科医生说，在扔掉防晒系数30之前，防晒霜和维生素D的关系要微妙得多。

According to Dr. Henry, former president of the American Academy of Dermatology, if sunscreen is supplied in a thick layer it "can effectively block sunlight and cause a lack of vitamin D in skin," He said. A thick layer is defined as roughly equivalent to about 1 ounce.

美国皮肤病学会前主席亨利博士说，如果涂厚厚的一层防晒霜，它“可以有效地阻挡阳光，导致皮肤缺乏维生素D，”他说。厚厚的一层大约相当于一盎司。

"However, in the real world ... most people apply less than this amount," Henry added.

“然而，在现实世界中…大多数人涂的量少于这个量，”亨利补充道。

So, you may not have to worry about vitamin D deficiency if you're not putting enough sunscreen on in the first place.

所以，如果你一开始就没有涂足够量的防晒霜，你可能就不用担心缺乏维生素D。

"For the vast majority of the public, there should be no concern with vitamin D levels, but for those who practice rigorous protection, namely, wearing photoprotective clothing, hats, staying in the shade when outdoors, and applying sunscreen -- they do have a higher risk," Henry said.

亨利说:“对于绝大多数公众来说，不必担心维生素D的含量，但是对于那些采取严格保护措施的人来说，比如穿防晒服，戴帽子，在户外时呆在阴凉处，涂防晒霜，他们确实有更高的风险。”

Vitamin D deficiency versus skin cancer risk

缺乏维生素D与皮肤癌风险的关系

Vitamin D is synthesized in skin when it's exposed to UVB wavelengths from the sun.

维生素D是当皮肤暴露在太阳的紫外线波长下合成的。

So if 15% to 20% of one's body surface is exposed to sunlight, unprotected, for 15 to 20 minutes, two to three times per week, one could achieve adequate vitamin D levels.

因此，如果一个人身体表面的15%到20%暴露在阳光下，不加保护，每周两到三次，每次15到20分钟，就可以达到足够的维生素D水平。

"When the skin tans, there is DNA damage, and so with repeated low exposure, the DNA damage could accumulate and potentially increase the risk of skin cancer and photoaging," Henry said. Squamous cell and basal cell carcinoma are the most common skin cancers in humans, and are correlated with the degree of one's sun exposure, while melanoma, the deadliest form of skin cancer is often the result of more intermittent, intense sun exposure, Henry explained.

亨利说:“当皮肤被晒成古铜色时，就会有DNA损伤，因此，反复低强度接触，DNA损伤就会累积，并可能增加皮肤癌和光老化的风险。”亨利解释说，鳞状细胞癌和基底细胞癌是人类最常见的皮肤癌，它们与人暴露在阳光下的程度有关，而黑色素瘤是皮肤癌中最致命的一种，它通常是间歇性、高强度阳光照射的结果。

"Patients need to use sun protection to minimize their risk for skin cancer, and yes it does impede the body's ability to make vitamin D. I tell patients if we found out cigarette smoking increased vitamin D levels, we wouldn't tell patients to smoke," said Dr. Patricia Farris, a dermatologist and fellow of the American Academy of Dermatology. "In other words, you can't recommend exposing patients to a known carcinogen (UV light) just to raise their vitamin D levels."

皮肤科医生、美国皮肤病学会研究员帕特里夏·法里斯说，“患者需要使用防晒物，以将患皮肤癌的风险降到最低，是的，它确实会阻碍身体合成维生素D的能力。我告诉患者，如果我们发现吸烟增加了维生素D水平，我们不会告诉患者去吸烟。”“换句话说，你不能建议患者暴露在已知的致癌物(紫外线)下，只是为了提高他们的维生素D水平。”

To reduce the risk of skin cancer and skin aging, dermatologists recommend practicing sensible photoprotection. That means wearing wide-brimmed hats, sunglasses, and sun protective clothing. Photoprotective clothing, which is labeled "UPF," is tightly weaved, and so "the amount of UV radiation that would penetrate is quite low," Henry said.

为了减少皮肤癌和皮肤老化的风险，皮肤科医生建议进行合理的光防护。这意味着要戴宽边帽子、太阳镜和防晒服。亨利说，标有“UPF”的光防护服编织紧密，因此“能够穿透的紫外线辐射量非常低，”亨利说。

"To achieve adequate vitamin D levels, it is best to take a multivitamin each day rather than relying on sun exposure. The former is simple and inexpensive, and at the same time prevents the development of skin cancer and skin aging," Henry said.

“为了达到足够的维生素D水平，最好每天服用多种维生素片，而不是依赖于晒太阳。”前者既简单又便宜，同时还能预防皮肤癌和皮肤老化。”亨利说。

Vitamin D supplements can also help, and are very effective for those who have low vitamin D levels, Farris added.

补充维生素D也有帮助，对维生素D水平低的人非常有效，法里斯补充说。

In addition to vitamin D supplements, the American Academy of Dermatology recommends getting vitamin D from a healthy diet that includes foods naturally rich in vitamin D, such as salmon, tuna, sardines, cod liver oil, and egg yolks, or foods and beverages fortified with vitamin D, such as cereals, yogurt, milk and orange juice.

除了维生素D补充剂，美国皮肤病学会建议从健康饮食中摄取维生素D，其中包括天然富含维生素D的食物，如三文鱼、金枪鱼、沙丁鱼、鳕鱼肝油和蛋黄，或富含维生素D的食物和饮料，如谷类、酸奶、牛奶和橙汁。