The fatty acid composition of banked human milk and infant formulas: the choices of milk for feeding preterm infants

The Nutritional Composition and Energy Content of Donor Human Milk: A Systematic Review

The American Academy of Pediatrics recommends donor human milk (DHM) as the preferred feeding strategy for preterm infants when the milk of the mother is unavailable, based on conclusive evidence of lower rates of necrotizing enterocolitis with DHM feedings compared with preterm infant formula. The nutritional composition of DHM may differ from maternal milk for many reasons including differences in maternal characteristics, milk collection methods, and the impact of donor milk banking practices. The purpose of this systematic review is to examine the literature regarding research on the fat, protein, carbohydrate, vitamin, and mineral composition of DHM obtained through nonprofit milk banks or commercial entities. PubMed, CINAHL, and Scopus databases were searched for articles published between 1985 and 30 April, 2019. In total, 164 abstracts were screened independently by 2 investigators, and 14 studies met all inclusion criteria. Studies were predominantly small (<50 samples) and measured macronutrients. Few studies assessed vitamins and minerals. Information bias was prevalent due to the use of a variety of analytical methods which influence accuracy and cross-study comparisons. Other sources of information bias included missing information regarding methods for protein and calorie assessment. Despite these limitations, existing research suggests the potential for 2-fold and greater differences in the fat, protein, and energy composition of DHM, with mean values for energy and fat often below clinical reference values expected for human milk. Further research is warranted regarding the nutritional composition of DHM, with a prioritization on measuring macronutrients and micronutrients using established reference methods.

Temporal Progression of Fatty Acids in Preterm and Term Human Milk of Mothers from Switzerland

We longitudinally compared fatty acids (FA) from human milk (HM) of mothers delivering term and preterm infants. HM was collected for 4 months postpartum at 12 time points for preterm and for 2 months postpartum at 8 time points for term group. Samples were collected from the first feed of the morning, and single breast was fully expressed. FA were analyzed by gas chromatography coupled with flame ionization detector. Oleic, palmitic and linoleic acids were the most abundant FA across lactation and in both groups. Preterm colostrum contained significantly (p < 0.05) higher 8:0, 10:0, 12:0, sum medium chain fatty acids (MCFA), 18:3 n-3 FA compared to term counterparts. Preterm mature milk contained significantly higher 12:0, 14:0, 18:2 n-6, sum saturated fatty acids (SFA), and sum MCFA. We did not observe any significant differences between the preterm and term groups for docosahexaenoic acid, arachidonic acid and eicosapentaenoic acid at any stage of lactation. Overall, preterm milk was higher for SFA with a major contribution from MCFA and higher in 18:2 n-6. These observational differences needs to be studied further for their implications on preterm developmental outcomes and on fortification strategies of either mothers’ own milk or donor human milk.

Lipid needs of preterm infants: updated recommendations

Long-chain polyunsaturated fatty acids (LCPUFAs) are of nutritional interest because they are crucial for normal development of the central nervous system and have potential long-lasting effects that extend beyond the period of dietary insufficiency. Here we review the recent literature and current recommendations regarding LCPUFAs as they pertain to preterm infant nutrition. In particular, findings that relate to fetal accretion, LCPUFA absorption and metabolism, effects on development, and current practices and recommendations have been used to update recommendations for health care providers. The amounts of long-chain polyunsaturated fatty acids (LCPUFAs) used in early studies were chosen to produce the same concentrations as in term breast milk. This might not be a wise approach for preterm infants, however, particularly for very and extremely preterm infants, whose requirements for LCPUFAs and other nutrients exceed what is normally provided in the small volumes that they are able to tolerate. Recent studies have reported outcome data in preterm infants fed milk with a docosahexaenoic acid (DHA) content 2-3 times higher than the current concentration in infant formulas. Overall, these studies show that providing larger amounts of DHA supplements, especially to the smallest infants, is associated with better neurologic outcomes in early life. We emphasize that current nutritional management might not provide sufficient amounts of preformed DHA during the parenteral and enteral nutrition periods and in very preterm/very low birth weight infants until their due date, and that greater amounts than used routinely likely will be needed to compensate for intestinal malabsorption, DHA oxidation, and early deficit. Research should continue to address the gaps in knowledge and further refine adequate intake for each group of preterm infants.

Nursing of malnourished children with emphasis on polyunsaturated fatty acids

Omega-3 (Omega-3) and omega-6 (Omega-6) fatty acids (FAs) are essential FAs needed for brain and retina development and maintenance of red blood cell (RBC) membranes. This study investigated the association between the profile of FAs in the membranes of RBCs and malnutrition in children. Demographic, anthropometric, and breast-feeding data and blood samples for analysis of FAs were obtained from malnourished and well-nourished children. The results indicate significant between-group differences in the profile of FAs. These findings support the need for adequate intake of Omega-3 FAs in promoting optimal growth and development processes and emphasize the role of nurses as providers of nutritional and anticipatory guidance for parents and caretakers.

Docosahexaenoic and arachidonic acid concentrations in human breast milk worldwide

Concentrations of the long-chain polyunsaturated fatty acids (LCPUFAs) docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6) in human breast milk are important indicators of infant formula DHA and AA concentrations, and recent evidence suggests that neural maturation of breastfed infants is linked to breast-milk LCPUFA concentrations. We report a descriptive meta-analysis that considered 106 studies of human breast milk culled to include only studies that used modern analysis methods capable of making accurate estimates of fatty acid (FA) profiles and criteria related to the completeness of reporting. The final analysis included 65 studies of 2474 women. The mean (+/-SD) concentration of DHA in breast milk (by wt) is 0.32 +/- 0.22% (range: 0.06-1.4%) and that of AA is 0.47 +/- 0.13% (range: 0.24-1.0%), which indicates that the DHA concentration in breast milk is lower than and more variable than that of AA. The highest DHA concentrations were primarily in coastal populations and were associated with marine food consumption. The correlation between breast-milk DHA and AA concentrations was significant but low (r = 0.25, P = 0.02), which indicates that the mean ratio of DHA to AA in regional breast milk varies widely. This comprehensive analysis of breast-milk DHA and AA indicates a broad range of these nutrients worldwide and serves as a guide for infant feeding.

Lipids in human milk

I have reviewed recent (March 1995-December 1997) papers on human milk lipids including many on fatty acid (FA) composition. The effects of maternal diets on the profiles are apparent. However, more data on the composition of milk lipids are needed. It is noteworthy that so few papers on milk FA composition have reported analyses using high-resolution gas-liquid chromatography columns. Two of these were on milk from women in North America. The diets in North America are varied and the number of analyses few. We do not have a reliable data base showing the ranges of biologically important acids. Except for the gangliosides, few new data on the other lipids appeared during this period.

Impact of solid food on plasma arachidonic and docosahexaenoic acid status of term infants at 8 months of age

We studied healthy term infants at 6 and 8 months of age to assess the effect of fat-containing solid foods (mashed veal, chicken, and pork provided in ready-to-feed cans) on plasma long-chain polyunsaturated fatty acid (LCP) status. Twenty-one infants were breast-fed and 49 were formula-fed. The fat of the formula contained 16.2% linoleic acid and 2.3% alpha-linolenic acid but no LCPs. The solid-food intake was assessed with a 7-day dietary record. Blood samples were obtained at 6 and 8 months of age, and the fatty acid composition of plasma cholesteryl esters (CE) and phospholipids (PL) were analyzed with capillary gas liquid chromatography. The solid food-derived fat intake was higher in the formula-fed than in the breast-fed group at 6 months, and it increased significantly in both groups (from 0.15 to 0.39 g/kg/day and from 0.24 to 0.43 g/kg/day in breast-fed and formula-fed groups, respectively). The relative plasma concentrations of arachidonic acid (20:4n-6) and docosahexaenoic acid (22:6n-3) were significantly lower in the formula-fed than in the breast-fed group at both 6 and 8 months. In the formula-fed group at 8 months, the proportion of solid food-derived fat correlated positively with plasma 20:4n-6, and the mean percentage of PL-20:4n-6 were 8.0% (95% confidence interval, 7.4-8.5) and 9.0% (8.3-9.7) in its lowest and highest quartiles, respectively. In the breast-fed group, solid food-derived fat intake had no effect on plasma 20:4n-6. The two groups were similar in that solid-food fat had no effect on plasma PL- or CE-22:6n-3. In conclusion, the introduction of meat containing solid foods to formula-fed infants increases their plasma 20:4n-6, but not to levels found in breast-fed infants. Further studies are needed to establish an optimal fatty acid composition of solid foods during weaning.