Lee Swanson Research Update

Soy Isoflavones Lower Total and LDL Cholesterol in Humans

April 2007

Soy isoflavones can significantly reduce serum total and LDL cholesterol, according to a meta-analysis published in the American Journal of Clinical Nutrition. LDL is often referred to as the "bad" cholesterol.

Researchers in Tokyo, Japan noted: "Clinical trials have reported the cholesterol-lowering effects of soy protein intake, but the components responsible are not known. This meta-analysis was primarily conducted to evaluate the precise effects of soy isoflavones on lipid profiles. The effect of soy protein that contains enriched and depleted isoflavones was also examined."

The team searched for English-language reports of randomized controlled trials published from 1990 to 2006 that described the effects of soy protein intake in humans. Eleven studies were selected for the meta-analysis.

Results showed that soy isoflavones "significantly decreased serum total cholesterol by 0.10.mmol/L and LDL cholesterol by 0.13 mmol/L. No significant changes in HDL cholesterol and triacylglycerol were found.

The largest reductions in LDL cholesterol were noted in people with high cholesterol levels, compared to those with normal levels.

American Journal of Clinical Nutrition 85(4):1148-1156, 2007

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