Effect of reduced dietary fat on estradiol, adiponectin, and IGF-1 levels in postmenopausal women with breast cancer

INTRODUCTION In recent years, epidemiological studies have strongly related obesity with an increased risk of developing postmenopausal breast cancer. The aromatization of fatty tissue increases the levels of estradiol and adiponectin, which is correlated with the body mass index (BMI). It is of interest to investigate the effect of reducing BMI on estradiol, adiponectin, and IGF-1, as reducing BMI could be a new strategy to limit the risk of recurrence during the adjuvant treatment of breast cancer. OBJECTIVE The aim of this study is to investigate the effect of reduced dietary fat on the levels of serum estradiol, adiponectin, and IGF-1 among postmenopausal Mexican women with breast cancer. METHODS In this controlled clinical trial, 100 female patients were randomly divided into two groups and followed for six months. Group 1 (n = 50) was subjected to reduced dietary fat, whereas Group 2 (n = 50) was subjected to a control diet. The levels of serum estradiol and testosterone were determined using an enzyme-linked immunosorbent assay, whereas the concentrations of adiponectin and IGF-1 were determined using a radioimmunoassay. RESULTS The patients subjected to reduced dietary fat showed a significant difference in BMI (27.93 ± 4.45 vs 26.05 ± 2.65; p = 0.01) and waist circumference (99.92 vs 91.59 cm; p = 0.0001) after the treatment. Moreover, a significant decrease in serum estradiol was observed (21.23 ± 14.32 vs 16.05 ± 10.25 ng/mL; p < 0.001). The adiponectin concentration also decreased significantly (47.53 ± 12.19 vs 42.52 ± 12.34 µg/mL; p = 0.004), while IGF-1 and testosterone did not show significant changes (p > 0.05). In addition, BMI had a relationship with serum adiponectin (r = -0.27; p = 0.02) and estradiol (r = 0.37; p = 0.001). CONCLUSION The current study shows that reducing BMI decreases serum estradiol and adiponectin. Large clinical trials are needed to investigate the role of adiponectin in breast cancer development in obese women.