Health

Soya and health: emerging research areas

date
24.11.2015

Nutrition experts from around the world recently descended upon Berlin to attend Europe’s largest nutrition congress organized by the Federation of the European Nutrition Societies (FENS 2015, October 20-23).

Exciting new research on the benefits of soya on skin health and mental health was presented during a satellite symposium by Professor Mark Messina, from Loma Linda University (USA). He explained the proposed effects are likely due to the isoflavones naturally found in soya. Isoflavones have a similar chemical structure to estrogen and as such are able to bind to estrogen receptors (ER). However they are very different to the hormone estrogen. A more accurate description of isoflavones is SERMs (selective estrogen receptor modulators), preferentially binding to ERβ rather than ERα. For this reason isoflavones will have tissue specific effects.

Reducing wrinkles: The predominate ER in skin is ERβ and it’s been suggested ERβ maybe a novel target for skin health. As such, initial findings from clinical studies using soya isoflavones are showing promising results. A number of studies, from 3 to 6 months in duration, have shown isoflavones, with or without other bioactives, reduce wrinkles and increase collagen. The most impressive study, published last year, included 159 healthy postmenopausal women who were randomly assigned to one of 3 groups – placebo group, a treatment group receiving a daily supplement of 25mg of isoflavones with other bioactives (lycopene, Vitamin C, Vitamin E and omega-3 fatty acids) and a treatment group receiving 43mg of isoflavones with the same bioactives [i]. After 14 weeks the treatment groups observed a 10% reduction in crow’s feet wrinkle depth as a result of increased collagen synthesis. It’s likely this effect is due solely to the isoflavones as none of the other bioactives have been shown to increase collagen. Another unpublished study of 101 healthy postmenopausal women, this time receiving a dose of 100mg isoflavones a day along with similar bioactives, also demonstrated an improvement in crow’s feet wrinkles compared to baseline after 14 weeks.

Anti-depressant effects: Depression effects twice as many women as men which suggests reproductive hormones maybe involved in its aetiology. Estrogen therapy has been found to be beneficial in reducing depressive symptoms in menopausal women, but what about isoflavones? A large Italian study of 262 postmenopausal women found a significant reduction in depressive symptoms in those who took 54mg of genistein (the predominant isoflavone in soya) a day compared to a placebo after 2 years [ii]. Another study, involving 90 healthy Japanese postmenopausal women, found a significant reduction in depressive symptoms after taking 25mg of isoflavones a day for 8 weeks compared to a placebo [iii]. Finally in a small pilot study, 100mg of isoflavones a day was as effective as sertraline (an anti-depressant drug) in reducing symptoms of depression in depressed menopausal women. The benefits were even greater when a combination of isoflavones and sertraline were used compared to the individual treatments [iv].

[i] Jenkins G, et al. (2014) Int J Cosmet Sci. 36(1): 22–31

[ii] Atteritano M, et al (2014) Osteoporos Int 25:1123-1129

[iii] Hirose A, et al (2015) Arch Gynecol Obstet epub ahead of print

[iv] Estrella RE, et al (2014) Acta Pol Pharm 71(2):323-7.

author
- Lynne Garton

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