Metabolic effects of infusion of a structured-triglyceride emulsion in healthy subjects

Structured-triglyceride (STG) emulsions may have beneficial effects compared with traditional emulsions. We infused equimolar doses of STG and long-chain fatty acid triglyceride (LCT; Intralipid 20%) emulsions for 6 h into eight healthy subjects. Six subjects were also infused with either a low or a high dose of the STG emulsion. Blood concentrations of triglycerides and glycerol increased dose-dependently. In seven of the eight subjects the increase in serum triglyceride concentrations was greater during LCT infusion than during STG infusion. The molar ratio of medium- to long-chain fatty acids in the plasma after infusions of STG at medium and high rates was close to the compositional molar ratio of this emulsion (1:1), indicating that medium- and long-chain fatty acids were released at similar rates. During fat infusion there was a small but significant decrease in plasma glucose and a modest increase in serum beta-hydroxybutyrate concentrations but no hypoglycemia. Serum phospholipids increased significantly in all groups except the one receiving the low dose of STG. Plasma insulin, serum lactate, and serum cholesterol concentrations did not change. In conclusion, the capacity of healthy subjects to hydrolyze STG was at least as high as that to hydrolyze LCT. Plasma fatty acid profiles during fat infusions were similar to the fatty acid compositions of the infused emulsions.