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Isoflavones such as those from soy have been extensively researched, particularly for their potential use during the menopause. They are a type of plant or ‘phyto’ oestrogen and have chemical and functional similarities to 17-ß oestradiol – the most potent oestrogen we make and levels of which decline during the menopause. This is what makes isoflavones an obvious natural alternative to the more conventional hormone replacement therapy (HRT). They offer a weaker, plant form of oestrogenic support without some of the less desirable side effects of HRT. 

Research has found that isoflavones may be effective during the menopause at reducing the risks of osteoporosis, lowering cholesterol and preventing hot flushes. The main active components of soy isoflavones are daidzein, genistein and glycitein.

What’s particularly interesting however is the effect that friendly bacteria have on their absorption. Whilst many women take isoflavones in supplement form as a natural support during the menopause, few instinctively complement this with a probiotic supplement or pay close attention to their dietary habits to ensure it feeds a healthy intestinal microflora. And yet, scientific research on the subject suggests that beneficial bacteria may have a significant impact on whether isoflavones are likely to be effective or not.

It seems your composition of colonic microflora can significantly influence the biologic effects of isoflavones. Some of their potential health benefits are dependent on your capacity to convert isoflavones into key metabolites during digestion. In particular, some bacteria can convert the isoflavone daidzein into equol, which has even greater oestrogenic activity than daidzein.

Whilst research in this area is still fairly limited, it makes sense to pay close attention to nurturing a healthy balance of friendly bacteria at any time in your life and particularly during the menopause.

If you choose to supplement with isoflavones as a natural menopausal aid, team with a high quality probiotic supplement for fully rounded support.

Setchell KD, Clerici C. Equol: history, chemistry, and formation. J Nutr. 2010;140(7):1355S-1362S.  
Setchell KD, Clerici C, Lephart ED, et al. S-equol, a potent ligand for estrogen receptor beta, is the exclusive enantiomeric form of the soy isoflavone metabolite produced by human intestinal bacterial flora. Am J Clin Nutr. 2005;81(5):1072-1079.  
Setchell KD, Cole SJ. Method of defining equol-producer status and its frequency among vegetarians. J Nutr. 2006;136(8):2188-2193.  
Piazza, C, Privitera M G et al. Influence of inulin on plasma isoflavone concentrations in healthy postmenopausal women.  Am J Clin Nutr. September 2007 vol. 86 no. 3 775-780

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