High versus low medium chain triglyceride content of formula for promoting short-term growth of preterm infants

Most very low birth weight infants grow slowly in hospital after delivery. This causes concern because poor growth can link to neurodevelopmental impairments including decreased cognitive ability (IQ), speech, and reading skills when school-aged. Fat provides about half of the energy source (calories) in human breast milk, mostly as long-chain fatty acid triglycerides (LCT). As a way of improving growth, fat can be added to formula used to feed preterm infants. Fats in formula can contain triglycerides with long chain fatty acids or shorter medium chain fatty acids (MCT). MCT are more easily absorbed by the newborn infant with an immature digestive system. LCT are still important in the development of visual acuity and development of cell membranes and the brain. The review authors searched the medical literature. They found eight small controlled randomized studies looking at short-term growth (weight, length, and head circumference gain) in preterm infants fed with varying amounts of medium chain fats. The pattern of growth in infants fed exclusively with high MCT or low MCT formula for at least one week did not differ (five studies with 182 infants). These infants had a mean gestational age between 29 and 32 weeks, mean birth weights between 1 kg and 1.5 kg, and were aged one to six weeks. One study found a high degree of gastrointestinal intolerance with high MCT content and another did not. Development of necrotizing enterocolitis was not different. No studies addressed long-term growth or neurodevelopmental outcomes.