Monday June 23, 2014 (foodconsumer.org) -- University of Washington researchers reviewed 17 controlled clinical trials of isoflavones and amino acid supplements intended to treat hot flashes and other symptoms including mood, sleep, pain and cognitive function which women commonly experience during the menopausal transition and early post-menopause. The trials were published between 2004 and July 2011.

The review found the following:

Five trials demonstrated that two soy isoflavone preparations, 6 grams of soy germ extract per day and 25 grams of soy protein in soy nuts per day, were effective in decreasing hot flashes, but not other symptoms.  

Among seven trials of other isoflavones, six were found able to significantly reduce hot flashes; additionally, red clover in a dose of 80 mg per day significantly reduced mood symptoms; Rexflavone  at 350mg per day significantly reduced sleep symptoms in women with Kupperman Index>20; isoflavone powder at 90 mg per day and red clover at 80 mg per day were also found to significantly reduce pain.  One trial also showed red clover in a dose of 80 mg per day significantly reduced cognitive symptoms.

In one trial, red clover in a dose of 80 mg per day significantly improved hot flashes, mood, pain and cognitive symptoms.  The magnolia bark extract combination was able to  significantly reduce hot flashes, mood, and sleep symptoms.

Equol dietary supplements in a dose of 30 mg per day were effective in reducing mood symptoms in non-equal producing women.

Amino acids did not seem to provide any benefits for women at menopause or during early postmenopause.

The review concluded "Isoflavone trials yielded significant reductions on hot flashes and co-occurring symptoms during the menopausal transition and postmenopause."

Thomas AJ, Ismail R, Taylor-Swanson L, Cray L, Schnall JG, Mitchell ES, Woods NF.  Effects of isoflavones and amino acid therapies for hot flashes and co-occurring symptoms during the menopausal transition and early postmenopause: A systematic review.   Maturitas. 2014 May 28. pii: S0378-5122(14)00159-5. doi: 10.1016/j.maturitas.2014.05.007.