1. Introduction
oxidant damage
SKIN
These authors contributed equally to this work.Preliminary findings from multiple studies indicate that dietary intake of soy-derived isoflavones exert beneficial effects on the skin including defense against oxidant damage, stimulation of collagen synthesis, and increased hydration. This study aims to investigate how oral supplementation of a soy protein isolate with added isoflavones (SPII) affects components of photoaging such as facial wrinkles and dyspigmentation, and skin biophysical measures such as skin hydration and sebum excretion in postmenopausal women. This 6-month prospective, randomized double-blind controlled study was conducted on 44 postmenopausal women with Fitzpatrick skin types I, II, and III who were randomized to receive either casein protein or SPII. A high-resolution facial photography system was used to measure wrinkle severity and pigmentation at 0, 8, 16, and 24 weeks. Skin biophysical measurements included skin hydration and sebum production. The average wrinkle severity was decreased in the SPII intervention group at week 16 and week 24 by 5.9% and 7.1%, respectively, compared to the baseline. Compared to the casein group, average wrinkle severity was significantly decreased at week 16 (Plant-derived isoflavones are naturally occurring nonsteroidal compounds that resemble estrogens and are commonly classified as phytoestrogens [The main dietary sources of isoflavones for humans are soybean and soy-derived products, which primarily contain daidzein and genistein [Isoflavones may modulate women’s health through multiple modalities. Supplementation has been shown to mitigate multiple symptoms of perimenopausal and postmenopausal women [Postmenopausal women are more susceptible to facial aging due to a shift in hormonal balance and decrease in collagen synthesis [Food-based interventions have previously demonstrated modulatory effects on skin aging [Foods rich in antioxidants such as vitamin E (alpha-tocopherol) have also been implicated in facial wrinkles and pigmentation. Almonds are one example of a food that contains alpha-tocopherol. Two studies demonstrated that daily consumption of almonds in postmenopausal women with Fitzpatrick skin types 1–3 for either 16 or 24 weeks resulted in a significant decrease in wrinkle severity and facial pigment intensity [Soy isoflavones have garnered interest for a range of functions including their antioxidant, phytoestrogenic, and anti-inflammatory properties [As a result of these findings with soy isoflavones and soy protein, there has been growing interest to assess the intake and supplementation of soy-based products for skin health. A previous study assessing postmenopausal women with Fitzpatrick skin types 1–3 who were supplemented with a mixture of soy isoflavones, lycopene, vitamin C, vitamin E, and fish oil for 14 weeks showed a reduction in wrinkle depth [The current study builds on all of these preliminary studies to comparatively study soy protein containing isoflavones (SPII) against a calorie-matched casein protein without added isoflavones. Specifically, this study investigates how supplementation with SPII shifts skin health including the appearances of wrinkles and pigmentation as well as skin biomechanical properties such as hydration and sebum production. 