Summary: Reduced crying and favourable stool characteristics in Chinese infants fed milk fat-based formula

This summary has been adapted from “Reduced crying and favourable stool characteristics in Chinese infants fed milk fat-based formula, Asia Pac J Clin Nutr. (2020).”

Human breast milk is the optimal food to meet all the nutritional needs of a newborn child. However, some mothers cannot or choose not to breastfeed their young. In these situations, a substitute of infant formula must be used to help the infant reach their energy and nutritional needs. One of the most important nutritional aspects of human milk is the fat content. The fat in human breast milk not only helps with the energy levels of the infant, but also helps support digestive gut health and comfort (1). Fat found in human breast milk is mainly composed of triglycerides, which contains glycerol backbone and three fatty acids which are attached to the sn-1, sn-2 and sn-3 position, respectively. 

In human breast milk the most common triglycerides found are long chain saturated fatty acids (LCSFA) (2). Long chain refers to a fatty acid with 12 or  more carbon atoms, and ‘saturated’ refers to fatty acids that do not contain double bonds along the fatty acid chain. It is reported that half of the LCSFA in human breast milk is palmitic acid and of that 70-88% of the palmitic acid in human breast milk is attached at the sn-2 position (3). Unsaturated fatty acids in human breast milk are found predominantly on the sn-1 and sn-3 position. Many infant formulas on the market today make up for the fat content by utilising vegetable oils. The differences between these vegetable oil triglycerides structures is that they have different length compositions, for example LCSFA is not the predominant structure in vegetable oils and the attachment site for palmitic acids in vegetable oils is not in the sn-2 position. This slight change in positioning is responsible for gut irritation in infants as the digestive enzymes (lipases) are only able to hydrolyse the fatty acids at the sn-1 and sn-3 position. When palmitic acid and other vegetable oil fatty acids are liberated from the glycerol backbone they are generally not readily absorbed by the gut like those in the sn-2 position. As a result, these free fatty acids have a tendency to cross react with calcium ions to form hard soap particles in the infant gut (4). The result is problems with excretion of faeces, low absorption ability for fats and minerals and increased intestinal discomfort (5). In order to determine if vegetable oil based infant formulas have any impact on infant digestive health, a study was conducted by the Shanghai Institute for Paediatric Research, where babies were divided into four groups , IF1, IF2, IF3, IF4.  All groups were given different formulas for the study. IF1 was an infant formula with milk fat and vegetable fat, IF2 and IF4 were formulas containing exclusive vegetable oil blends and IF3 was a vegetable oil infant formula with a palm oil free fat-blend. Faecal samples were collected and analysed and questionnaires were given to parents in order to assess sleep patterns, stool colour and stool consistency. The results of this study showed that the infants IF1 had softer stools compared to the other groups. In addition, IF1 babies had different stool colours than the infant formulas that contained exclusive vegetable oil formula blends. The questionnaire revealed that IF1 fed babies had less incidences of  abdominal distension, burping, flatulence, diarrhoea and constipation. Fussiness and lengths of time of distress (as measured by crying) in  infants was shorter in infants in group IF1 during the night. The faecal analysis showed that infants fed IF1 had less fatty acid calcium soaps in their faeces. From this data it appears that the milk fat mixed with vegetable oil blends is better suited for the needs of the infant compared to infant formulas containing only vegetable fats (6). Kendamil believes in a science and evidence based approach to formula development which is why we include the use of full fat bovine milk in our formula over exclusive use of vegetable oil blends. 

References:

1.  Sheng XY, Buthmanaban V, Vonk MM, Feitsma AL, Parikh P. Reduced crying and favourable stool characteristics in Chinese infants fed milk fat-based formula. Asia Pac J Clin Nutr. 2020;29(1):144-151. doi: 10.6133/apjcn.202003_29(1).0019. PMID: 32229453.
2. Hageman JHJ, Danielsen M, Nieuwenhuizen AG, FeitsmaAL, Dalsgaard TK. Comparison of bovine milk fat and vegetable fat for infant formula: Implications for infant health. Int Dairy J. 2019;92:37-49. doi: 10.1016/j.idairyj.2019.01.005.
3. Straarup EM, Lauritzen L, Faerk J, Høy C-E, Michaelsen KF. The stereospecific triacylglycerol structures and Fatty Acid profiles of human milk and infant formulas. J Pediatr Gastroenterol Nutr. 2006;42:293-9. doi: 10.1097/01.mpg.0000214155.51036.4f.
4. Yao M, Lien EL, Capeding MRZ, Fitzgerald M, Ramanujam K, Yuhas R, Northington R, Lebumfacil J, Wang L, DeRusso PA. Effects of term infant formulas containing high sn-2 palmitate with and without oligofructose on stool composition, stool characteristics, and bifidogenic city. J Pediatr Gastroenterol Nutr. 2014;59:440-8. doi: 10.1097/ MPG.0000000000000443.
5. Quinlan PT, Lockton S, Irwin J, Lucas AL. The relationship between stool hardness and stool composition in breast- and formula-fed infants. J Pediatr Gastroenterol Nutr. 1995; 20: 81-90. 10.1097/00005176-199501000-00014
6. Sheng XY, Buthmanaban V, Vonk MM, Feitsma AL, Parikh P. Reduced crying and favourable stool characteristics in Chinese infants fed milk fat-based formula. Asia Pac J Clin Nutr. 2020;29(1):144-151. doi: 10.6133/apjcn.202003_29(1).0019. PMID: 32229453.