Neonatal fat digestion and lingual lipase

Lingual lipase (LL) activity, pH, and products of fat hydrolysis were determined in gastric aspirates from preterm infants who received formula milk feeds by a nasogastric tube. In 1-hourly (n=9), 2-hourly (n=8) and 3-hourly (n=9) fed infants LL activity increased to reach its maximum value at 60, 90, and 120 min respectively after the feeds, and gastric pH levels fell from about 6.0 to <3.5. There was a reduction in triglyceride content to 50% of the initial value, measured immediately after a feed, and the products of hydrolysis were mainly diglycerides and FFA. In a subsequent study 3-hourly fed infants (n=8) had a feed followed by a bottle feed, and then a bottle feed followed by a tube feed on successive days (cross-over). The LL activity observed after a bottle feed (mean maximal value 23.8 μmol FFA/ml/h) was significantly higher than after a tube feed (19.1 μmol FFA/ml/h). It is suggested that substantial triglyceride hydrolysis takes place in the stomach due to lingual lipase, and sucking seems to enhance enzyme production.