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Metabolic utilization of linoleic acid from fat emulsion in infants during total parenteral nutrition
J Ghisolfi1, J Garcia, O Couvaras
1Groupe D'Etudes en Nutrition Infantile Faculte de Medecine de Purpan, Universite Paul Sabatier, Toulouse, France.
Insights
Intravenous soybean oil emulsion effectively provides linoleic acid (C18:2w6) for infants, normalizing fatty acid levels and supporting prostaglandin synthesis. This indicates normal metabolic utilization in infants receiving total parenteral nutrition.
Area of Science:
- Biochemistry
- Pediatric Nutrition
- Metabolism
Background:
- Infants receiving long-term total parenteral nutrition (TPN) require essential fatty acids.
- Soybean oil emulsion is a common lipid source in TPN, providing linoleic acid (C18:2w6).
- Understanding linoleic acid metabolism is crucial for optimizing TPN in infants.
Purpose of the Study:
- To investigate the metabolic utilization of intravenous linoleic acid (C18:2w6) in infants.
- To assess the conversion of linoleic acid to higher fatty acid homologues and its role in prostaglandin biosynthesis.
- To evaluate the adequacy of a specific linoleic acid dosage in TPN for infants.
Main Methods:
- Analysis of plasma and erythrocyte phospholipid fatty acids in 21 infants receiving TPN with soybean oil emulsion.
- Comparison of fatty acid profiles with 26 age-matched healthy controls.
- Measurement of 24-hour urinary excretion of prostaglandins PGE1 and PGE2.
Main Results:
- Intravenous linoleic acid supply (350 mg/kg/24h) normalized erythrocyte phospholipid fatty acid distribution, including higher homologues (C18:3w6, C20:3w6, C20:4w6).
- This suggests normal delta 6 and delta 5 desaturation activities in infants on TPN with this linoleic acid dose.
- Urinary prostaglandin levels (PGE1, PGE2) were comparable to healthy children, indicating adequate prostaglandin synthesis.
Conclusions:
- Intravenous linoleic acid from soybean oil emulsion is effectively utilized by infants on TPN.
- The studied dose supports normal fatty acid metabolism and prostaglandin production.
- This dosage appears adequate for maintaining essential fatty acid status in infants requiring long-term TPN.
Abstract:
The metabolic utilization of linoleic acid (C18:2w6) from intravenous (iv) soybean oil emulsion via its conversion to higher homologues and prostaglandin biosynthesis was studied in 21 infants. The infants were of normal birth weight, in good clinical and metabolic condition, and aged from 1-4 months. They all received total parenteral nutrition after birth for more than 1 month; the only lipid was provided by iv Intralipid 20%, at levels approximating 350 mg/kg/24 h of linoleic acid (2.5% of the infants' total daily energy intake). Study of the fatty acids of plasma and erythrocyte phospholipids in these infants, compared to healthy controls of the same age (N = 26), showed that 350 mg/kg/24 hr of C18:2w6 supply resulted in normalization of erythrocyte phospholipid fatty acid distribution. This was particularly true of the higher homologues of C18:2w6 (C18:3w6, C20:3w6, and C20:4w6). This suggested that delta 6 and delta 5 desaturation activities are normal in these conditions with this C18:2w6 supply. These results were confirmed by the study of 24-hr urinary excretion of prostaglandins PGE1 and PGE2. With 350 mg/kg/24 hr of C18:2w6 supply their urinary levels were not significantly different from those observed in normal children of the same age receiving an equivalent oral C18:2w6 intake.