The Effect of Reduced Dietary Fat and Soy Supplementation on Circulating Adipocytokines in Postmenopausal Women: A Randomized Controlled 2-Month Trial

ABSTRACT

The reduced risk of breast cancer observed in Asia has been linked with diets rich in soy foods, and observational studies suggest that regular soy food intake is related to lower circulating levels of some inflammatory markers which have been implicated in breast cancer risk. However, short-term intervention studies with soy-based diets in small numbers of women have shown few significant changes in adipocytokine levels. This 8-wk dietary intervention study in 57 healthy postmenopausal women investigated whether soy food supplementation (50 mg isoflavones or 15 g soy protein in the form of tofu) or a very low-fat diet (11.3% of total energy), similar to the traditional Asian diet, is associated with beneficial effects on serum levels of the following adipocytokines: TNF-α, IL-6, adiponectin, and resistin. We found no statistically significant changes in the levels of these adipocytokines in association with the very low-fat diet or soy supplementation. Only the change in TNF-α levels between the very low-fat and control diet groups had borderline statistical significance. We conclude that ingestion of a very low-fat diet or a soy food supplemented diet for 8 wk does not significantly alter important circulating adipocytokines.

Acknowledgments

This study was supported by the Susan G. Komen Breast Cancer Foundation (BASIC99-00327, BCTR00-000709) and the University of Southern California/Norris Comprehensive Cancer Center Core Grant (5P03ES007048). The authors wish to thank the study subjects and staff of the GCRC, and Margaret Groves, M.Phil., ELS for her help in preparation of the manuscript.