OBJECTIVE To assess the effect of metformin on the metabolism of intestinally derived lipoproteins in nondiabetic individuals who were mildly overweight and glucose intolerant.

RESEARCH DESIGN AND METHODS A total of nine subjects with a BMI ≥ 25 kg/m² and fasting serum glucose ≤ 6.1 mmol/l and who were glucose intolerant were studied. The subjects underwent a vitamin A fat-loading test before and after a 3-month treatment with 850 mg metformin twice a day. The metabolic behavior of the postprandial lipoproteins was compared with that found in a group of 19 healthy normolipidemic individuals who participated in a previous study.

RESULTS Mean total plasma, chylomicron fraction, and nonchylomicron fraction retinyl palmitate (RP) pretreatment levels were 3.4-fold, 3.59-fold, and 3-fold higher, respectively, in the study group than in the normolipidemic group and were reduced by 50, 56, and 32%, respectively, after 3 months of metformin treatment. The decrease of chylomicron levels after treatment was positively correlated to the fasting triglyceride values before treatment (r = 0.73, P = 0.039) and to the serum insulin level at 120 min of standard glucose loading before treatment (r = 0.91, P = 0.002).

CONCLUSIONS Metformin was shown to be beneficial in the clearance of postprandial lipoproteins in nondiabetic individuals who were mildly overweight and glucose intolerant.