Addition of inulin to a moderately high-carbohydrate diet reduces hepatic lipogenesis and plasma triacylglycerol concentrations in humans

BACKGROUND: A high-carbohydrate, low-fat diet is recommended for the prevention of atherosclerosis, because it reduces plasma cholesterol concentrations. However, such a diet can increase plasma triacylglycerol concentrations--an undesirable side effect. The addition of nondigestible carbohydrate could reduce the risk of elevated triacylglycerol concentrations. OBJECTIVE: The objective was to determine whether the addition of a moderate dose of inulin to a moderately high-carbohydrate diet would decrease hepatic lipogenesis and plasma triacylglycerol concentrations and have a cholesterol-lowering action. DESIGN: Eight healthy subjects were studied twice in a double-blind, randomized, placebo-controlled crossover study after consuming for 3 wk a moderately high-carbohydrate, low-fat diet (55% of total energy) plus an oral placebo or 10 g high-performance inulin/d. Hepatic lipogenesis and cholesterol synthesis (deuterated water method), plasma lipid concentrations, fatty acid synthase, acetyl-CoA carboxylase 1, and sterol responsive element binding protein 1c messenger RNA concentrations were measured in adipose tissue at the end of the 2 diet periods. RESULTS: Plasma triacylglycerol concentrations and hepatic lipogenesis were lower after inulin than after placebo ingestion (P < 0.05), but cholesterol synthesis and plasma cholesterol concentrations were not significantly different between the 2 groups. None of the adipose tissue messenger RNA concentrations changed significantly after inulin ingestion. CONCLUSIONS: The addition of high-performance inulin to a moderately high-carbohydrate, low-fat diet has a beneficial effect on plasma lipids by decreasing hepatic lipogenesis and plasma triacylglycerol concentrations. These results support the use of nondigestible carbohydrate for reducing risk factors for atherosclerosis.