Fat emulsions are more than energy suppliers.

The type of triglycerides in exogenous fat emulsions as well as the phospholipid: triglyceride ratio influences the plasma clearance. The plasma clearance cannot be used for indicating the utilization of fat emulsions as energy substrate. Introducing exogenous fat in replacement of part of the calories provided by glucose reduces a series of complications associated with large glucose intake. There are exchanges of triglycerides, esterified cholesterol, phospholipids and apoproteins between exogenous lipids and endogenous lipoproteins, depending on the composition of exogenous lipid emulsions. These interactions can significantly modify the composition of both, exogenous particles and endogenous lipoproteins. In future it will become essential to determine the removal site of 'exogenous remnants'. Future progress will allow a better understanding of the influence of these modifications on the metabolism of endogenous lipoproteins and the utilization of exogenous fat emulsions.