Dietary lipid droplet size and phospholipids modulate lipid digestion and absorption in early life nutrition, an in vitro study

Lipid droplet structure differs in infant nutrition and may impact lipid digestion and absorption. Human milk (HM) contains large milk fat globule membrane (MFGM) coated lipid droplets, while standard infant formula (sIF) and sIF with added MFGM (sIFM) contains small protein coated droplets. Concept infant formula (cIF, Nuturis®) mimics HM's structure. Digestion of the infant formulae (IFs) and HM was simulated under infant conditions. Digests were sampled in time and free fatty acids (FFA) were analyzed to determine lipolysis rates. Lipid absorption was tested by digest incubation on Caco2-TC7 transwells for 6 and 16 h. sIF and sIFM had higher lipolysis rates than cIF and HM. FFA release patterns differed between the IFs and HM. sIFM showed increased triglyceride secretion and larger intracellular lipid droplets compared to sIF. The sIF and sIFM had higher lipolysis rates, while cIF was closer to breast milk in lipolysis and absorption rate. • • Lipolysis and absorption of IFs with small or large droplets vs HM was tested. • • Small droplets (sIF and sIF + MFGM) showed faster lipolysis rates vs large (cIF and HM). • • HM lipolysis resulted in more unsaturated FFA (OA, LA) and less free PA vs IFs. • • MFGM added to sIF increased TG secretion, cIF and HM secretion was not different. • • Lipid structure affects lipid availability; cIF is more similar to HM than sIF.