A systematic review and meta-analysis of the omega-3 and omega-6 long-chain polyunsaturated fatty acid composition of donor human milk for preterm infants

Background: Donor human milk (DHM) is commonly used to supplement feeds for preterm and sick infants with insufficient breastmilk. It is unclear whether DHM provides the same amounts of omega-3 and omega-6 long-chain polyunsaturated fatty acids (LCPUFA), particularly docosahexaenoic acid (DHA) and arachidonic acid (AA), as maternal breastmilk. Objective: To conduct a systematic review summarizing the evidence on the LCPUFA composition of DHM. Methods: PubMed was searched up to January 2026 to identify studies reporting DHA and AA profiles of DHM. Where possible, potential influences of DHM LCPUFA composition such as milk collection methods and pasteurization were summarized. We performed meta-analyses sub-grouped on the fatty acid expression modes (molar% or weight%). Results: Twenty studies were included in this systematic review; sixteen were eligible for meta-analysis. Sample sizes ranged from three to 168 DHM samples per study and LCPUFAs were generally reported as relative rather than absolute concentrations. Pooled means were 0.25% DHA (95% CI 0.19, 0.31) and 0.50% AA (95% CI 0.41, 0.58). Higher DHA proportions were associated with omnivorous diets and earlier lactation stages. Compared to preterm colostrum and transitional (7–14 days postpartum) milk, DHM contained lower relative levels of DHA and AA. Pasteurization had little effect on relative LCPUFA levels. Conclusions: DHM has an LCPUFA profile similar to mature breastmilk but has lower proportions of DHA and AA than preterm colostrum or transitional breastmilk. Due to limitations in reporting of LCPUFA composition, absolute amounts delivered to infants given DHM are unclear, but it is likely preterm infants require supplemental DHA and AA. Registration: This review was registered on Open Science Framework (DOI: 10.17605/OSF.IO/HMX2F).