Positive Health Online

Abstract

ALLEN and co-workers, Johns Hopkins University School of Nursing, Baltimore, MD 21205, USA, jallen@son.jhmi.edu, have investigated the effect of soy isoflavones on the blood lipid profile in postmenopausal women.

Background

Some clinical trials have demonstrated a beneficial effect of dietary soy protein on improving lipoproteins. Research also has documented that serum lipoproteins and some lipoprotein subclasses are altered as a consequence of menopause, resulting in a more atherogenic lipid profile. The aim of this study was to determine the effects of isolated soy protein-containing isoflavones on lipoproteins and lipoprotein subclasses in postmenopausal women with borderline to moderate low-density lipoprotein cholesterol elevations.

Methodology

This was a randomized, double-blind, controlled clinical trial including 216 postmenopausal women. After a 4-week run-in period with a casein protein-based supplement, participants were randomly assigned to continue the casein placebo or receive soy protein-containing isoflavones for a period of 12 weeks.

Results

In the soy group, the total cholesterol, low-density lipoprotein cholesterol, and low-density lipoprotein particle number decreased significantly as compared with the placebo group at 6 weeks. Although this decrease continued at 12 weeks in the soy group, the difference from the placebo group was attenuated for total cholesterol and low-density lipoprotein particle number. Multivariate analyses controlling for age, race, change in weight, change in dietary fat intake, and change in kilocalorie energy expenditure, revealed that treatment remained a significant independent predictor of change in total cholesterol (p = 0.01), low-density lipoprotein cholesterol (p = 0.02), and low-density lipoprotein particle number (p = 0.002) after 6 weeks of dietary soy.

Conclusion

Increased consumption of soy protein replacing animal protein that is high in fat may help improve atherogenic lipid profiles.

References

Allen JK, Becker DM, Kwiterovich PO, Lindenstruth KA, Curtis C. Effect of soy protein-containing isoflavones on lipoproteins in postmenopausal women. Menopause 14 (1): 106-114, Jan-Feb 2007.