Sugar in the Diet Can Lead to Acne

Any link between sugar and acne has long been dismissed. But now scientists are taking another look.

In recent years, studies have shown that what matters may not be sugar itself but a food's glycemic index, or the speed and extent to which it raises blood glucose levels. Foods that have a high glycemic index - and as a result raise glucose levels rapidly - cause the body to release a flood of insulin and other hormones, which some scientists suspect can stimulate oil production and inflame the skin.

To test the theory, scientists recruited 50 men and boys ages 15 to 25, all of them with acne, and followed their progress for 12 weeks. Some subjects stuck to a typical diet that included high-glycemic foods like white bread, sweetened cereals and pasta, and the others were given foods higher in protein and lower on the glycemic scale, like fish, whole-grain breads and fruit.

At the end of the study, published in 2007, the subjects on the low-glycemic diet had far greater reductions in skin lesions and other symptoms of acne than the control group. They also showed reductions in their levels of free, circulating androgens, the male hormones known to cause acne, suggesting that hormones played a role.

Other studies have found similar connections between high-glycemic foods and acne, though scientists say more research is needed.

日常饮食中的糖类可能导致长粉刺

在很长一段时间内，糖类和粉刺之间的关系一直被忽略。不过，现在科学家们对两者的关系有了另外的看法。

近几年，一些研究表明，真正引起血液中葡萄糖升高的原因或许不是糖类本身，而是食物的血糖指数、血糖的扩散速度和扩散范围。高血糖指数的食物能使葡萄糖快速增加，引起体内释放大量胰岛素和其他荷尔蒙，科学家们认为这些激素刺激了油脂的分泌和皮肤发炎。

为了证明这个理论，科学家们征募了50个15~20岁的成年男子和男孩，他们都长粉刺。在接下来的12个星期，他们中有的人按典型的饮食习惯一直吃高血糖指数的食物，如白面包、甜谷物类和甜面条等，其他人吃高蛋白和低血糖指数的食物，如鱼，全麦面包和水果。

研究结果在2007年发表，坚持低血糖饮食的被试者皮肤明显变好，脸上的粉刺比另一组被试者少得多。同时，他们的男性荷尔蒙释放量和循环量也明显减少。男性荷尔蒙是引起粉刺的其中一个原因。

在高血糖指数食物与粉刺关系的其他研究中，有类似的发现，尽管科学家们认为这方面的更多研究是必须的。