Alpha linolenic acid in cholesterol esters: a marker of alphalinolenic acid intake in newborns

Objective: To evaluate a-linolenic acid (ALA) (18:3 n-3) and linolenic acid (LA) (18:2 n-6) in cholesterol esters (CE) as markers of ALA and LA dietary intakes in preterm infants. Subjects: Forty-five preterm infants: two groups fed different formulas, the third fed human milk. Design: ALA and LA dietary intakes were precisely recorded in each infant to accurately determine the cumulative amount of ingested ALA and LA during two intervals: (i) between the second day after the first significant formula intake (DO) and the fifteenth day (D15); and (ii) between DO and the first day of the 37th week of post-conception age (W37). The corresponding amounts of ingested ALA and LA were related to ALA and LA levels determined by capillary column gas-liquid chromatography in plasma cholesterol esters at D15 and W37, respectively. Results: ALA in CE was very significantly correlated to D0-D15 and D0-W37 ALA intakes (0.66; P= 0.0001 and 0.70; P= 0.0001), respectively. LA in CE was weakly correlated to D0-D15 LA intakes (0.03; P = 0.01) and whatever the group (human milk or enriched formula) the correlation was lost at W37. Conclusion: In preterm infants, ALA in CE can be considered as representative of ALA dietary intakes, whereas LA in CE appears as a poor marker of LA intakes.