Amino Acids Not Beneficial for Postmenopausal Women

L-isoleucine ineffective for hot flushes; L-isoleucine and L-valine don't reduce serum homocysteine levels

MONDAY, July 14 (HealthDay News) -- In postmenopausal women, treatment with the amino acid L-isoleucine does not reduce hot flushes, and treatment with L-isoleucine and another amino acid -- L-valine -- either alone or in combination, has no effect on fasting serum homocysteine levels, according to research published in the July issue of Obstetrics & Gynecology.

Thomas Guttuso, M.D., of the University at Buffalo, State University of New York, and colleagues randomly assigned 100 postmenopausal women who had at least five moderate to severe hot flushes per day to one of four groups (phase 1/phase 2): placebo/L-valine; placebo/L-valine and L-isoleucine; L-isoleucine/L-valine; and L-isoleucine/L-valine and L-isoleucine. The duration was 12 weeks for phase 1 and 10 weeks for phase 2.

The researchers observed no significant differences between the L-isoleucine and placebo groups for any of the outcome measures in phase 1. At week 12, the mean decrease in the hot flush composite score was actually higher in the placebo group than in the L-isoleucine group (25 percent versus 13.9 percent). In phase 2, they found that neither L-isoleucine nor L-valine was associated with any significant changes in fasting serum homocysteine levels compared to placebo.

"A possible explanation for the lack of effects of the amino acids on serum homocysteine in this study, in contrast to the pilot study, may be the more rigorous processing protocol of the blood samples in this study," the authors write.

Guttuso is the inventor of a patent owned by the University of Rochester, covering the use of gabapentin and related compounds for treating hot flushes.

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