The metabolic effects of two different lipid emulsions used in parenterally fed premature infants--a randomized comparative study.

OBJECTIVE: To compare the effects of two different lipid emulsions, based on soybean oil and olive oil respectively on plasma lipid concentrations and acylcarnitine profile of very low birth weight infants.

DESIGN: Randomized comparative study.

PATIENTS AND METHODS: Forty very low birth weight infants, ≤32 weeks of gestational age and receiving at least 40% of the calorie taken by parenteral nutrition from lipid solution at 14th day of life were evaluated. Group I (n=20) received soybean oil based lipid emulsion (Intralipid®) and Group II (n=20) received olive oil based lipid emulsion (Clinoleic®).

MAIN OUTCOME MEASURES: Plasma lipid concentrations and acylcarnitine profile were assessed.

RESULTS: Triglyceride, cholesterol, high and low density lipoprotein levels, liver function tests were similar between two groups whereas very low density lipoprotein level was statistically lower in Group I (p<0.05). Free carnitine levels were 15.73±10.67 in Group I and 34.25±22.18 μM in Group II (p=0.012) and hexanoyl carnitine levels 2.18±2.10 in Group I and 0.38±0.12 μM in Group II, respectively (p=0.005). Plasma medium chain acylcarnitine levels were significantly higher in Group I.

CONCLUSIONS: Low levels of very low density lipoprotein in Group I may be a way of hemostasis to keep the serum triglyceride within normal levels. Lower free carnitine levels in soybean oil-based group is the result of carnitine need during the mitochondrial transport of long chain fatty acids. In Group I, due to the inefficient transport of medium chain fatty acids into the mitochondria, medium chain acylcarnitines accumulate in plasma. This may be the reason of lower carnitine levels in Group I. We suggest that higher levels of hexanoyl carnitine, reflecting defective mitochondrial transport of hexanoyl which leads immunsupression, may be the cause of higher sepsis risk in Group I.