Fatty acid absorption in preterms on formulas with and without long-chain polyunsaturated fatty acids and in terms on formulas without these added

Abstract

Background/objective: Long chain polyunsaturated fatty acids have beneficial effects in preterm neurophysiological development and are semi-essential. Their levels and variation in plasma and red cells in term and preterms are better known than their intestinal absorption. In this paper the absorption of supplemented arachidonic acid (AA) and docosahexaenoic acid (DHA) is evaluated in a preterm group. Design: Four newborn randomized groups were studied. Group T comprised 11 terms on regular formula. Preterms: group P (n = 9) was on a classic preterm formula. Intervention: groups PA (n = 9) and PB (n = 13) were on the same formula but PB contained AA and DHA in similar proportion to breast milk. At 20 days a 3 day metabolic balance was taken for Ca, Pi, Mg, Mg, total fat and individual fatty acids (C8-C24, saturated unsaturated). Results: Calcium absorption was (mean ± s.d.) 51 ± 13% in terms. In preterms it was respectively 45 ± 18, 38 ± 11 and 37 ± 21%. Total fat absorption was 92.0±8.0% in terms, and from 95.0±2.0 to 91.0±8.0% in preterms. Absorption of 8:0, 10:0 and 12:0 showed a very high and constant rate despite significant intake differences (715-33 mg/kg/day). Linoleic acid and α-linolenic acid were absorbed in the three groups at around 94% regardless of a greater LA intake in group P. Details of absorption (mg/kg/day) were: for AA, intake 17±7, fecal excretion 5±4, net retention 12±5 (75.0±18%); for DHA, intake 10±3, fecal excretion 3±2, net retention 6±4 (62.3±30%). Conclusion: Intestinal absorption of fatty acids is high and is comparable in terms and preterms as regards the studied acids. Longer acids were less well absorbed. The supplemented amounts of AA and DHA were less well absorbed and probably not impairing calcium absorption.