有痘的人不建议吃牛奶或者奶制品，按理说，酸奶也属于奶制品，虽然一般奶制品指的是牛奶、奶粉、奶酪、奶片、奶油等。

我看到的文献没有特别提及酸奶要不要也被排除在外，故今天中午写信给一位研究痤疮与营养的专家Bill Danby， Adjunct Assistant Professor of Surgery (Dermatology) ，Geisel School of Medicine at Dartmouth，请他给个准信儿，得到他的回复是：

唯一诚实的答案是：我们还不知道。

他有一位40岁的希腊病人，认为希腊酸奶提“安全的” ，她只在吃酸奶三个月后，左脸颊长了一些早期的炎症性痤疮。

关于发酵对牛奶中可促进痤疮的活性成分的影响（即：可提升IGF-1的酪蛋白、可提升胰岛素的乳清蛋白），暂不清楚。这方面的研究也相当缺乏，一方面是研究很费钱，一方面也许是农场主们施加的政治压力导致FDA和农业部一直没有批准此类研究，显然，乳业界对此类研究肯定是不感兴趣的。

目前，他对爱吃酸奶的病人的建议是：吃发酵的植物“酸奶”，也就是发酵豆奶，这在美国很常见，只要找到含糖量较低的就好了。

他的回信写得很认真，我就不逐字翻译了，把通信原文附在后面，有兴趣的童鞋可以自己阅读一下哈：

Dear Professor Danby,

It was nice to read your articles about nutrition and acne, and I'd like to say thanks for the articles. Since you suggested all milk and dairy foods be excluded from acne patients' diet, I'd like to ask for your confirmation if yoghurt should also be excluded?

After fermentation, there may be some changes happened to milk's ability in elevating androgen levels, 5-alpha hydroxy reductase activity and androgen receptor sensitivity. The active factors/proteins may be denatured, degraded or inactivated by lactic acid or some other factors. But I've not read any reports about yoghurt and acne by now.

I found, time by time, in inflammatory oily skin, young girls/ladies bear heavy hair/vellus (mustache) in the area above upper lip. This was unusual when I was in that age. I am not sure if this is related to the tremendous consumption growth of milk and dairy foods in recent 20 years.

Your reply would be highly appreciated. Millions of acne patients in China are expecting for your answer:)

Thanks and best regards!

Sincerely yours, Binghan

The Air Force Clinical College, Anhui Medical University, China

==========以下为回信============

The only accurate and honest answer is that we simply do not know.

I have one Greek woman patient of about 40 who thought that Greek yoghurt was 'safe'.

She developed (after only three months of consumption) early inflammatory acne (on her left chin) after 3 or 4 years with no problem on a zero-dairy diet. Not a large series - only one, but she was impressed!

We need to know the levels of **all** the bioactive substances in yoghurt, indeed we need new assays of all the bioactive substances in all dairy products. I am not aware of any studies that show the impact of fermentation on the components of the casein that increase IGF-I, nor the components of the whey that increase insulin. Likewise, we are ignorant of the impact of fermentation on the steroid hormone profile. This is an area that is wide open for investigation. The problem is that it is expensive. Here in the USA, I have been unable to get the FDA or the US Department of Agriculture to conduct these studies. I strongly suspect that there is political pressure coming from the farming community. Certainly, the dairy industry is not interested in doing this work.

The approach I take with my yogurt loving patients is to recommend that they use non-dairy yogurt. Soy-based yogurt is fairly common here in the USA. It comes in many flavors. Then the problem becomes finding one that is not heavily dosed with sugar. That usually stimulates a concern (driven by the Internet) about phytoestrogens. I explain to patients that all plants have phytoestrogens - just like all humans have estrogens, but humans have been eating plants for millions of years, and there doesn't seem to be a problem.

Your observation about the fine hair on the upper lip is valid, I think. Here in the USA, we are growing much heavier individuals, bulkier and more muscled, in both sexes. I think this is a general expression of stimulation from dairy hormones. If you have not read the work by Melnik, please let me know and I will send along some PDFs.

I know this response provides more questions than answers, and I encourage you help find the answers.

Thank you for writing.

PS my book "Acne: Causes and Practical Management" is due to launch in January. My editors tell me there will be a Mandarin addition, but I won't be proofreading that one. And I don't know when it comes out.

Bill Danby

F W Danby, MD FRCPC

President, Hidradenitis Suppurativa Foundation, Inc

Adjunct Assistant Professor of Surgery (Dermatology)

Geisel School of Medicine at Dartmouth

Private Practice, Manchester, NH