Food carbohydrates and plasma lipids--an update.

An increase in dietary energy from carbohydrates is usually associated with a moderate increase in fasting plasma triglycerides--but not cholesterol--in the first weeks after the change. In the long-term the triglyceride returns to or to near the original concentration. Ordinary intakes of sucrose or fructose do not have any special elevating effect on plasma triglycerides in most normal and diabetic people, provided energy balance is not changed. Although biochemical theory predicts that fructose is more lipogenic than glucose, nearly all the animal reports of elevated plasma lipids with sucrose- or fructose-rich diets were obtained with diets unnaturally high in these sugars, and in rats and not other species. In humans, increased (fasting) triglycerides are observed with very high intakes, > 35% of energy from sucrose or > 20% of energy from fructose, and even then triglyceride elevation is unlikely unless the subjects are male and dietary fat is saturated. In people with hypertriglyceridemia (type IV), reduction of percent dietary carbohydrate is not recommended; this implies a higher percent of energy from fat, which leads to higher daylong triglycerides. However, in a minority of these patients, reduction of refined sucrose (or fructose) may be followed by lower triglycerides. Epidemiologically, high carbohydrate intakes are associated with low plasma cholesterol and variable plasma triglyceride concentrations.