Fermented soy milk is more than good for you!
Daily consumption of soy milk is beneficial to the skin of premenopausal women, but it has to be fermented by lactobacilli (special lactic bacteria) to improve the balance of the intestinal microbiota, according to a Japanese study.
Soy milk contains vegetable substances (isoflavones) which are believed to provide a lot of health benefits. They are similar to female hormones (estrogens) and could prevent breast cancer, limit menopause and osteoporosis symptoms and improve skin condition. However, to be useful, isoflavones must be absorbed by the body. A Japanese team demonstrated that a single intake of soy milk fermented by lactobacilli and enriched with isoflavones increased the impact of the isoflavones’ active substance.
What about a therapeutic purpose?
To know if fermented soy milk has more beneficial properties for the skin and the intestinal flora than regular soy milk, researchers recruited 52 premenopausal women. Every day for a period of eight weeks, some of them had to drink soy milk fermented by lactobacilli and enriched with isoflavones while the others had to drink unprocessed soy milk. The impact of both kinds of milk was analyzed thanks to a questionnaire submitted to the participants regarding their skin quality (elasticity, dryness, fineness...) and several medical exams (skin examination, urine and stool analysis).
Few differences between the two groups
In both groups, the same isoflavone level fluctuation and the same satisfaction regarding skin quality were observed, and the latter improvement was confirmed through a skin examination. According to the researchers, a positive link was established between isoflavone level and skin quality. They found a single difference: the composition of the microbiota of the women who drank fermented soy milk improved to include more “good” bacteria. The authors concluded that, if consumed regularly, soy milk improves skin condition by increasing the beneficial effect of isoflavones; and that fermented soy milk has, as an additional benefit, a positive impact on the intestinal microbiota.
T. Nagino et al. Effects of fermented soymilk with Lactobacillus casei Shirota on skin condition and the gut microbiota: a randomised clinical pilot trial. Beneficail Microbes, 2017, online.