Acne as a Potential New Target for Soy Isoflavones

While the pathophysiology of acne vulgaris is, at a minimum, complex (and that’s putting it lightly), it is generally accepted that androgens such as dihydrotestosterone (DHT) can play a prominent role, especially in adult women with acne. Although it is not approved by the US Food and Drug Administration, the utilization of antiandrogens such as spironolactone (see my discussion of spironolactone use in adult females in the October issue of Cutis) has become standard practice for many US dermatologists who treat this patient population. Joined only by combined oral contraceptives, antihormonal therapies for acne are somewhat limited. Therefore, effective as well as safe additions are needed.

In a study published online on July 20 in Dermato-Endocrinology, Riyanto et al evaluated the potential of orally administered soy isoflavones for treatment of acne in adult women based on both lesion count over time and corresponding changes in DHT levels. Soy isoflavones such as genistein, daidzein, and glycitein have established effects on androgen metabolism through inhibition of 3β-hydroxysteroid dehydrogenase, 17β-hydroxysteroid dehydrogenase, and the 5α-reductases. The study was double-blinded and conducted over 12 weeks, and various confounders were accounted for, including body mass index and menstrual irregularities; however, the sample size was relatively small (N=40), with participants equally randomized to treatment with either a placebo or the soybean isoflavone (160 mg daily). The results were determined to be significant (P<.05) based on the statistical analysis, which found that the isoflavone group had a lower lesion count after 12 weeks as well as a drop in serum DHT levels. Baseline lesion counts and serum DHT levels were not statistically significant when compared to the placebo group.

What’s the Issue?

Am I saying you should recommend to all of your adult female acne patients that they should run out and buy soy isoflavone supplements? Probably not. Forgetting even the study limitations, we face a daily struggle with reproducibility when it comes to over-the-counter supplements given these products are not regulated with the same scrutiny as prescription products or devices. Unfortunately, the degree of variability between 1 manufacturer to another can be broad, with shelf life stability often being the greatest issue. Are all soy isoflavone supplements created equal? I don’t know, and I can assure you that most regulatory bodies don’t know either. Walking down the vitamin aisle with countless versions of the same product can be acne inducing in itself.

The data is certainly interesting and novel for this disease state. A larger study certainly is warranted, although as we increase the number of studies, I wonder if we will receive mixed data as witnessed with the breast cancer prevention studies with soy; some showed intake was advantageous, other did not (see suggested readings below if interested in learning more). To end on a positive note, the way I see it is that soy isoflavones could possibly become a cheaper addition to—not a replacement for—our vast yet active ingredient–lacking armament of acne treatments. Time will hopefully tell. How do you think these study results will impact the treatment of acne?

We want to know your views! Tell us what you think.

Suggested Readings

• Travis RC, Allen NE, Appleby PN, et al. A prospective study of vegetarianism and isoflavone intake in relation to breast cancer risk in British women. Int J Cancer. 2008;122:705-710.
• Key TJ, Sharp GB, Appleby PN, et al. Soya foods and breast cancer risk: a prospective study in Hiroshima and Nagasaki, Japan. Br J Cancer. 1999;81:1248-1256.
• Zaineddin AK, Buck K, Vrieling A, et al. The association between dietary lignans, phytoestrogen-rich foods, and fiber intake and postmenopausal breast cancer risk: a German case-control study. Nutr Cancer. 2012;64:652-665.