Carbohydrate-induced hypertriacylglycerolemia: historical perspective and review of biological mechanisms

Current trends in health promotion emphasize the importance of reducing die tary fat intake. However, as dietary fat is reduced, the dietary carbohydra te content typically rises and the desired reduction in plasma cholesterol concentrations is frequently accompanied by an elevation of plasma triacylg lycerol. We review the phenomenon of carbohydrate-induced hypertriacylglyce rolemia, the health effects of which are among the most controversial and i mportant issues in public health nutrition today. We first focus on how sem inal observations made in the late 1950s and early 1960s became the basis f or subsequent important research questions and areas of scientific study. T he second focus of this paper is on the current knowledge of biological mec hanisms that contribute to carbohydrate-induced hypertriacylglycerolemia. T he clinical rationale behind mechanistic studies is this: if carbohydrate-i nduced hypertriacylglycerolemia shares a metabolic basis with endogenous hy pertriacylglycerolemia (that observed in subjects consuming high-fat diets) , then a similar atherogenic risk may be more likely than if the underlying metabolic mechanisms differ. The third focus of the paper is on both the p ositive metabolic changes that occur when high-carbohydrate diets are consu med and the potentially negative health effects of such diets. The review c oncludes with a summary of some important research questions that remain to be addressed. These issues include the level of dietary carbohydrate that induces carbohydrate-induced hypertriacylglycerolemia, whether the phenomen on is transient or can be avoided, whether de novo lipogenesis contributes to the phenomenon, and what magnitude of triacylglycerol elevation represen ts an increase in disease risk.