Variation in [U-13C] alpha linolenic acid absorption, beta-oxidation and conversion to docosahexaenoic acid in the pre-term infant fed a DHA-enriched formula.

Docosahexaenoic acid (DHA) is an integral component of neural cell membranes and is critical to the development and function of the CNS. A premature delivery interrupts normal placental supply of DHA such that the infant is dependent on the nature of the nutritional support offered. The most abundant omega-3 fatty acid in pre-term formulas is alpha linolenic acid (ALNA), the precursor of DHA. This project studied the absorption, beta-oxidation and conversion of ALNA to DHA by pre-term infants ranging from 30-37 wk of corrected gestation. [U-(13)C] ALNA was administered emulsified with a pre-term formula to 20 well pre-term infants on full enteral feeds. Enrichment of (13)C in stool and as (13)CO(2) in breath was used to estimate absorption across the gut and partitioning toward beta-oxidation respectively. Excretion of the administered dose of (13)C in stool ranged from 2.0 to 26.2%; excretion decreased with increasing birth gestation. Appearance as (13)CO(2) on breath ranged from 7.6 to 19.0%. All infants synthesised eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and DHA with the least mature having the highest cumulative plasma DHA. These results show considerable variation suggesting that the worst absorption of ALNA and the greatest production of DHA occur in infants born at the earliest gestation.