Abstract 3273: Meta-Analysis Confirms Soy Protein’s Cholesterol Lowering Efficacy
In 1999, the U.S. Food and Drug Administration (FDA) approved a health claim for soy protein and coronary heart disease (CHD) risk reduction. Recently, the FDA announced its intention to re-evaluate the health claim and existing data on the relationship between CHD and soy protein as a result of recent reviews that have questioned the efficacy of soy protein in cholesterol lowering. We identified 152 studies from Medline, recent reviews and meta-analyses between 1977 and 2008 on the relationship of soy protein and cholesterol reduction. Using the Food and Drug Administration’s 2007 guidance for “Evidence-Based Review System for the Scientific Evaluation of Health Claims”, studies were evaluated and ranked, and low quality studies were excluded for the meta-analysis. Changes in total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) (95% confidence intervals) were calculated using a random-effects model. Compared to control subjects, consumption of soy protein was associated with significant mean reductions in TC levels of 9.54 mg/dL (7.03 to 12.05 mg/dL) and LDL-C levels of 7.12 mg/dL (5.80 to 8.45 mg/dL). Subgroup analyses were performed separately for normocholesterolem-ics and hypercholesterolemics. Soy protein consumption reduced TC levels by 11.05 mg/dL (8.00 to 14.11 mg/dL) in hypercholesterolemics and by 4.24 mg/dL (0.99 to 7.49 mg/dL) in normocholesterolemics. The reduction in LDL-C levels in hypercholesterolemics was 8.71 mg/dL (6.99 to 10.43 mg/dL) and in normocholesterolemics was 5.10 mg/dL (2.95 to 7.26 mg/dL). All analyses showed statistically significant lowering of both TC and LDL-C with soy protein consumption. The stability and robustness of these estimates were confirmed by sensitivity analyses. In conclusion, the results of this meta-analysis continue to support a meaningful and statistically significant cholesterol reduction with the consumption of soy protein. This new body of evidence also strongly justifies maintaining the currently approved health claim for soy protein and CHD risk reduction.