Effect of milk fat-based infant formulae on stool fatty acid soaps and calcium excretion in healthy term infants: two double-blind randomised cross-over trials

Abstract

Background Palmitic acid (PA) is predominantly esterified at the SN-2 position of triacylglycerols in human milk. PA at the SN-2 position is more efficiently absorbed and results in reduced formation of PA soaps, as well as reduced fatty acid (FA) and calcium malabsorption. Bovine milk fat (MF), a natural source of SN-2-palmitate, was used in the fat blend of infant formulae (IF) in the current study to investigate its effect on stool fatty acid soaps, calcium excretion and stool characteristics. Methods Two double-blind, randomised cross-over trials (CS1, CS2) were conducted in parallel with healthy term, formula-fed infants aged 9–14 weeks. After a two-week run-in period, infants in CS1 (n = 17) were randomly allocated to receive either a 50% MF-based formula (50MF) or a 100% vegetable fat (VF) formula; in CS2 (n = 18), infants received either a 20% MF-based formula (20MF) or the VF formula, in a 2 × 2-week cross-over design. At the end of each two-week intervention period, stool samples were collected for FA, FA soaps and calcium excretion analysis and stool consistency was assessed according to the Amsterdam Infant Stool Scale (AISS). Results MF-based groups showed no significant difference in PA in stools compared to VF group, although reduced stool PA soaps (CS1: 111.28 ± 18.33 vs. 220.25 ± 29.35 mg/g dry weight, p < 0.0001; CS2: 216.24 ± 25.16 vs. 233.94 ± 35.12 mg/g dry weight, p = 0.0023), total FA soaps and calcium excretion (CS1: 46.40 ± 5.27 vs. 49.88 ± 4.77 mg/g dry weight, p = 0.0041; CS2: 46.20 ± 4.26 vs. 50.47 ± 6.71 mg/g dry weight, p = 0.0067) were observed. Furthermore, the 50MF group showed a favourable lower mean stool consistency score compared to the VF group (1.64 ± 0.49 vs. 2.03 ± 0.19, p = 0.0008). Conclusions While the use of bovine MF in IF did not affect PA concentrations in stool, lower excretion of palmitate soaps, total FA soaps and calcium was seen in healthy term infants. 50MF formula also showed improved stool consistency. The use of MF in IF could be an interesting approach to improve gut comfort and stool characteristics in infants, warranting further research. Trial registration Netherlands Trial Registry Identifier: NTR6702. Date registered: December 01, 2017.

Development of the digestive system in early infancy and nutritional management of digestive problems in breastfed and formula-fed infants

“…In addition, there are infant formulas, including formulas with bovine cream or anhydrous milk fat and whole goat milk formulas, that contain milk fat blended with vegetable oils to provide total and sn -2 palmitic acid without the use of palm oil or structured triglycerides. 46,77 Manios et al 78 found that infants fed a formula with up to 50% of its lipids as milk fat had lower excretion of palmitate soaps, total fatty acid soaps and calcium compared to infants fed a control vegetable oil-based formula.…”

“…48 In addition, whole goat milk formulas and cow milk-based formula including milk fat mixed with vegetable oils have also been proven to improve stool characteristics (Table 2). 77,78…”

Effect of Bovine Milk Fat-based Infant Formulae on Microbiota, Metabolites and Stool Parameters in Healthy Term Infants in A Randomized, Crossover, Placebo-controlled Trial

“…Parents collected stool samples of ~30 g during the last three days (days 12-14) of the run-in period and each of the two intervention periods following a previously described procedure (5). The frozen samples were shipped in dry ice to Euro ns Laboratories, Madison, Wisconsin, USA, to analyse the fat composition and calcium concentration as described previously (5).…”

“…Recently, the similarity index has been developed as a tool to design the optimal composition of fat blends (4). Indeed, an infant formula with a mixed fat blend of selected vegetable oils and bovine milk fat (50%) reduced faecal soap formation and improved stool consistency compared to a standard IF with 100% vegetable fat in a recent clinical study (5). In addition to an effect on stool consistency, faecal soaps might also in uence gut microbiota composition and activity.…”

The effect of calcium palmitate on bacteria associated with infant gut microbiota

“…However, palmitic acids at the sn‐1 and sn‐3 position are released into the gut and can then bind minerals like calcium to form insoluble soaps, especially calcium palmitate (CP). Such soaps can cause a hard stool, and lower the calcium and fatty acids absorption (Manios et al, 2020; Havlicekova et al, 2015). Changed stool consistency suggests that CP formation might influence the gut microbiota.…”