Long-chain polyunsaturated fatty acid nutrition in breastfed and complementary fed South African infants
Introduction: Adequate intake of essential fatty acids (EFAs) and long-chain polyunsaturated FAs (LCPUFAs) during infancy are important for optimal growth and development. During the first six months of life, the growing infant receives LCPUFAs through breast milk or LCPUFA-supplemented infant formula. Therefore, lactating women should consume adequate amounts of preformed LCPUFAs to ensure adequate transfer of LCPUFAs to the infant through breast milk. However, the introduction of LCPUFA-poor complementary foods at the age of six months may lead to a reduction in blood LCPUFA levels. It is estimated that nearly 22 million infants in low- and middle-income countries are at risk of insufficient intake of LCPUFA. Particularly, LCPUFA intakes from breast milk and complementary foods in South Africa were estimated to be below the recommended intakes. Furthermore, studying different fatty acid (FA) patterns instead of individual FAs considers the different interactions and interrelations that may exist. Thus, in addition to determining the plasma phospholipid FA patterns of infants, the main objective of this study was to assess LCPUFA nutrition of South African infants during breastfeeding and the complementary feeding period. Methods: In a randomised controlled trial, six-month-old infants from a peri-urban township were randomly selected to receive daily, a small-quantity lipid-based nutrient supplement (SQ-LNS) containing EFAs linoleic acid (LA) and alpha-linolenic acid (ALA) (SQ-LNS); daily SQ-LNS with both EFAs and the LCPUFAs docosahexaenoic acid (DHA) and arachidonic acid (AA) (SQ-LNS-plus), or a control group receiving no supplement. The SQ-LNSs additionally contained micronutrients. Plasma total phospholipid FA composition (% of total FAs) was measured at baseline (n=353) and at 12 months (n=293) (infants with FA data at 6 and 12 months, n=148). Baseline characteristics were assessed to determine associations of total plasma phospholipid FA patterns with feeding practices, growth and psychomotor development. Feeding practices and dietary intakes were assessed using a structured questionnaire and unquantified food frequency questionnaire, respectively. Psychomotor development was assessed using the Kilifi Developmental Inventory (KDI) and anthropometric measurements were measured in all infants. In a cross-sectional study, red blood cell (RBC) total phospholipids as well as fore-, mid-feed and hind-milk samples of lactating mothers (n=100) of 2-4-month-old infants living in a peri-urban township were assessed. RBC total phospholipid and breast milk FAs were analysed by using quadrupole gas chromatography -electron impact-tandem mass spectrometry (GCMS/MS). Results: In six-month-old South African infants, infants who received formula milk had higher scores, while breastfed infants had lower scores for the ‘high EFAs with low DHA and AA’ and ‘high MUFA and nervonic acid' patterns. Infants who received breast milk, semi-solid foods or cow's milk but not infant formula milk, had higher scores, while formula-fed infants had lower scores for the ‘high n-6 LCPUFA’ pattern. Infants who received breast milk and semi-solids had higher scores for the 'trans-FA pattern'. The ‘high MUFA and nervonic acid’ and ‘trans-FA’ patterns were positively associated with psychomotor development, while no associations were found with growth. Results from the intervention study showed the geometric mean (95% CI) plasma total phospholipid DHA and AA contents of 4.1 (4.0-4.3) and 11.5 (11.2-11.8) % respectively. Breastfed infants had significantly higher plasma DHA and AA than their non-breastfed counterparts. Infants receiving the SQ-LNS-plus had significantly higher plasma DHA (4.52 [4.3-4.9]) at 12 months than the infants in the control group (3.8 [3.6-4.0]). The effect size was higher in infants who no longer received breast milk (? = 1.148 [95% CI= 0.597, 1.699]) than in infants who were still receiving breast milk (? = 0.544 [95% CI= 0.179, 0.909]). The two SQ-LNSs had no effect on plasma AA. Breast milk DHA and AA levels of 100 lactating women were (geometric mean [95% CI]) 0.25 (0.24, 3.71) and 0.81 (0.79, 0.83) %, respectively. Breast milk LA and ALA contents were 19.7 (19.1, 20.1) and 0.81 (0.77, 0.88) % respectively. Breast milk ALA and DHA levels were higher in mid-feed milk than in fore-milk while AA levels did not change during a feeding session. Breast milk DHA positively correlated with maternal RBC DHA. The association between breast milk DHA and maternal RBC DHA was stronger in fore-milk and became weaker in mid-feed and hind-milk. Fish consumption was positively associated with higher RBC EPA composition. Conclusion: The results from this research suggest breast milk is a predominant source of n-6 LCPUFAs at the age of six months, however, South African infants receiving infant formula milk may be at risk of inadequate LCPUFA intake. Furthermore, continued breastfeeding and consumption of LCPUFA-enriched SQ-LNS improved plasma DHA status of infants at 12 months. Infants who no longer receive breast milk, particularly, may benefit most from a SQ-LNS enriched with LCPUFAs. The results from this research further indicate that during breast milk EFA and LCPUFA composition may change within a feed. Also, breast milk DHA was associated with maternal RBC DHA status which confirms that DHA is selectively transferred to the breastfeeding infant within-feed. However, the high content of LA observed in the breast milk of women in this population seemingly reflects a high dietary intake of LA. Thus, it is plausible that lactating women living in a peri-urban township in South Africa may not be consuming adequate dietary sources for n-3 LCPUFAs.
- Health Sciences