Impact of medium- and long-chain triacylglycerols and sn-2 palmitate on temperament development in term infants: potential role of gut Bifidobacterium.

The intervention group receiving formula supplemented with MLCTs and sn-2 palmitate showed significant improvements in multiple temperament scores compared to the control group after two months.

• Significant improvements were observed in activity (p = 0.039), mood (p = 0.023), persistence (p = 0.001), and distractibility (p = 0.006) compared to the control group.
• Temperament was assessed using the Early Infancy Temperament Questionnaire at baseline (1 month postpartum) and endpoint (3 months postpartum).
• The intervention group (IG, n = 65) showed temperament changes similar to the breastfed group (BG, n = 66), suggesting the supplemented formula approximated breastfeeding outcomes.
• The control group received formula without MLCTs and sn-2 palmitate (CG, n = 48).

The relative abundance of Bifidobacterium in the intervention group was significantly increased compared to the control group and was comparable to the breastfed group.

• Bifidobacterium relative abundance was significantly higher in the IG compared to the CG (p = 0.011).
• Bifidobacterium levels in the IG were not significantly different from those in the BG (p = 0.759).
• Gut microbiome analysis was conducted via 16S rRNA amplicon sequencing on stool samples collected at baseline and endpoint.
• These findings suggest that MLCTs and sn-2 palmitate supplementation may shift the formula-fed infant gut microbiome toward a breastfed-like profile.

The decrease in relative abundance of Blautia was significantly more pronounced in the intervention group than in both the control and breastfed groups.

• The reduction in Blautia relative abundance in the IG was significantly greater than in the CG (p = 0.002).
• The reduction in Blautia relative abundance in the IG was also significantly greater than in the BG (p = 0.048).
• This finding suggests a distinct effect of MLCTs and sn-2 palmitate supplementation on Blautia compared to both conventional formula and breastfeeding.

A positive correlation was observed between changes in activity temperament scores and the relative abundance of Bifidobacterium.

• The correlation between changes in activity scores and relative abundance of Bifidobacterium was r = 0.25, p = 0.002.
• Temperament characteristics more broadly were associated with microbiome genera in early infancy.
• This association supports a potential gut-brain axis mechanism by which Bifidobacterium may mediate temperament development.

This study was a prospective, parallel, open-label controlled trial with infants divided into three feeding groups at 4 weeks postpartum.

• The three groups were: intervention group receiving formula with MLCTs and sn-2 palmitate (IG, n = 65), control group receiving formula without these lipids (CG, n = 48), and breastfed group (BG, n = 66).
• MLCTs and sn-2 palmitate constitute 70-80% of human breast milk lipids.
• The trial is registered under NCT05295030.
• The authors' previous work showed that this formula supplementation promoted adequate weight gain, but effects on neuropsychological development and gut microbiome were previously unclear.