Changes in plasma lipoprotein concentrations and composition in response to a low-fat, high-fiber diet are associated with changes in serum estrogen concentrations in premenopausal women

Abstract

We have investigated the effects of a low-fat, high-fiber diet on plasma lipid and lipoprotein levels and serum sex hormone concentrations in 22 normal premenopausal women (mean age, 25.8 ± 3.8 years). Participants consumed a baseline diet for 4 weeks (40% of calories as fat, 16% as saturated fatty acids, 8% as polyunsaturated fatty acids, 400 mg/d cholesterol, and 12 g/d dietary fiber) and then a low-fat, high-fiber diet for 8 to 10 weeks (16% to 18% of calories as fat, 4% as saturated fatty acids, 4% as polyunsaturated fatty acids, 150 mg/d cholesterol, and 40 g/d fiber). Blood samples for determination of plasma lipids and serum hormones were obtained during the follicular and luteal phases of the menstrual cycle during both diets. Compared with the baseline diet, the low-fat, high-fiber diet resulted in significant decreases in total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol concentrations during both the follicular and luteal phases (TC, −14% and −16%; LDL cholesterol, −14% and −17%; and HDL cholesterol, −15% and −18%, respectively). During the follicular phase but not the luteal phase on the low-fat, high-fiber diet, women exhibited significant increases in plasma triglyceride ([TG] 22%) and very-low-density lipoprotein (VLDL)-TG (36%) concentrations. During the follicular phase, serum estrone sulfate concentrations decreased by 25% ( P < .0001) when subjects were fed the low-fat, high-fiber diet. During this phase of the low-fat, high-fiber diet relative to the baseline diet, changes in HDL cholesterol levels were significantly and positively associated with changes in estrone levels ( r = .49, P < .02), and the ratio of TC to HDL cholesterol was inversely associated with the changes in estradiol and free estradiol levels ( r = −.47 and r = −.43, P < .05, respectively). Our data are consistent with the concept that in premenopausal women, low-fat, high-fiber diets reduce estrone sulfate levels and both LDL cholesterol and HDL cholesterol levels without affecting the TC to HDL cholesterol ratio. Moreover, changes in estrone and estradiol levels are associated with changes in HDL cholesterol and HDL-TG levels.