Extremely preterm infants receiving standard care receive very low levels of arachidonic and docosahexaenoic acids

Abstract

Background & aims: Adequate supply of arachidonic (ARA) and docosahexaenoic (DHA) acids is essential for brain development, and extremely preterm infants may be at risk of deficiency. Current levels of ARA and DHA given to extremely preterm infants and the amounts available for accretion have not been established, although recent evidence suggests DHA intake is at a level likely to lead to severe deficits. This study quantified the omega-6 and omega-3 polyunsaturated fatty acid (PUFA) intakes from all sources in the first six weeks of life of preterm infants in standard care. In addition, the relationship between blood levels of circulating cytokines and PUFAs was explored.

Methods: Single centre longitudinal study with omega-6 and omega-3 PUFA intake data analysed from all sources for 17 infants born <28 weeks gestation. At six weeks of age the infants' whole-blood fatty acid levels were measured along with a range of cytokines and chemokines analysed by Luminex^® multiplex array.

Results: ARA intake was significantly below international recommendations in weeks 1-5 (all p < 0.05), and DHA intake was significantly below recommendations in week 1 (p < 0.0001). The amounts of ARA and DHA available for accretion were significantly below estimated accretion rates in all weeks (all p < 0.001). Mean ARA and DHA intakes were correlated with their respective blood levels (r = 0.568, p = 0.017 and r = 0.704, p = 0.002). There were significant relationships between MIP-1β and blood DHA levels (rs = 0.559, p = 0.02) and between RANTES and omega-6:omega-3 PUFA ratio (rs = -0.498, p = 0.042).

Conclusions: This study establishes that extremely preterm infants receive insufficient intakes of ARA and DHA. Moreover, blood fatty acid levels may provide a useful measure of intake, where establishing sufficient consumption could have clinical importance. There may also be important interactions between long-chain PUFA status and markers of inflammation, which requires further study.

Keywords: Arachidonic acid; Breast milk; Docosahexaenoic acid; Inflammation; Preterm infants.