Evidence for impaired lipolysis in abdominally obese men: postprandial study of apolipoprotein B-48- and B-100-containing lipoproteins.

BACKGROUND

Abdominal obesity has been associated with postprandial hypertriglyceridemia. The contribution of intestinally and hepatically derived lipoproteins to this exaggerated postprandial lipemic response is not known.

OBJECTIVE

We examined the associations between body fatness, fat distribution, and postprandial apolipoprotein (apo) B-48 and apo B-100 concentrations measured in triacylglycerol-rich lipoproteins (TRLs).

DESIGN

Dietary fat tolerance was investigated in 50 men aged 28-67 y. The subjects were given a test meal containing 60 g fat/m(2) body surface area and providing 64% of energy from fat, 18% from carbohydrates, and 18% from protein. The meal provided 7524-9196 kJ, depending on body surface area. Blood samples were collected every 2 h over an 8-h period.

RESULTS

The increase in plasma triacylglycerol after the meal resulted from increases in both apo B-48- and apo B-100-containing lipoproteins. The apo B-100 concentration was the strongest contributor (R(2) = 69.6%, P = 0.0001) to postprandial triacylglycerol in total TRLs; the postprandial increase in triacylglycerol was best predicted by the apo B-48 concentration (R(2) = 32.7%, P = 0.0001). Visceral abdominal fat was significantly associated with high postprandial TRL apo B-48 and apo B-100 concentrations (r = 0.30-0.44, P < 0.05). After the meal, the apo B-100 concentration in small TRLs decreased in 12 subjects. These men showed features of the insulin resistance-dyslipidemic syndrome, including more visceral fat (P = 0.07) and an altered fasting metabolic profile.

CONCLUSION

A lower lipolytic capacity may contribute to the exaggerated and prolonged postprandial lipemia among abdominally obese men.