We studied the effect of 2 mg micronized 17 beta-estradiol replacement therapy, administered orally during 6 weeks, on postprandial lipid and retinyl palmitate (RP) metabolism. In the human postprandial state, atherogenic chylomicron remnant particles are produced. RP is incorporated into the core of newly synthesized chylomicrons and can be used as a marker of chylomicrons and chylomicron remnants. Six normolipidemic (plasma cholesterol, 5.63 +/- 0.83 mmol/L; plasma triglycerides, 1.47 +/- 0.69 mmol/L) postmenopausal women (amenorrhea > 1 yr; aged 55.5 +/- 4.0 yr) received an oral fat load (50 g/m2 fat as cream, with 60,000 IU RP/m2) before and after 6 weeks of 17 beta-estradiol treatment. Plasma RP areas under the curve decreased significantly from 27.1 +/- 15.9 to 16.6 +/- 13.2 mg/h.L-1 (P = 0.01). Fasting cholesterol concentrations in intermediate density lipoproteins decreased significantly. Fasting and postprandial plasma triglyceride levels did not change. These findings indicated that 17 beta-estradiol improved the postprandial elimination of potentially atherogenic lipoprotein remnants.