Immunonutrition for Preterm Infants

Abstract

Care and outcomes for very preterm infants continue to improve, but important causes of mortality and acute and long-term morbidity associated with prolonged hospitalisation remain. Necrotising enterocolitis (NEC) and late-onset infection have emerged as the major causes of death beyond the early neonatal period and of neurodisability in very preterm infants. Although the pathogenesis of these conditions is incompletely understood, it appears to be related to the content and mode of delivery of the enteral diet, particularly the impact of immunonutrients from human breast milk on the microbial and metabolic balance within the immature intestine. Evidence exists to support investment in measures to help mothers to express breast milk as the primary source of nutrition for their very preterm infants. In the absence of maternal milk, pasteurised donor breast milk provides protection against NEC, but its nutritive adequacy is not clear and its cost-effectiveness is uncertain. Supplementation with individual immunonutrients, including immunoglobulins and lactoferrin, has not been shown to be effective in preventing NEC or infection in randomised controlled trials. The evidence base for prebiotics and probiotics is stronger, but concerns exist about the choice, safety and availability of formulations. Other strategies – including avoidance of drugs such as gastric acid suppressants that compromise innate immunity, as well as evidence-based progressive feeding strategies that reduce exposure to invasive interventions – are emerging as key components of care packages to reduce the burden of NEC, infection and associated growth and developmental faltering for very preterm infants.

Nutrition in Necrotizing Enterocolitis and Following Intestinal Resection

“…The specific mechanisms by which breast milk is protective continue to be studied. However, several non-nutrient components have been found to contribute to the immune functions of the gastrointestinal tract and augment mucosal integrity [21,22]. These include secretory IgA, growth hormones (epidermal growth factor, insulin, and insulin-like growth factor), polyunsaturated fatty acids, and oligosaccharides.…”

Immunometabolic approaches to prevent, detect, and treat neonatal sepsis

“…In fact, undernutrition is the most common cause of secondary immunodeficiency in the world [84], with malnutrition in the critical early months of development having a profound and long-lasting impact on immunity. Nutrition, both enteral and parenteral, has an important role in the prevention of neonatal sepsis by minimizing nutrient loss and stimulating the maturation of the gastrointestinal tract, one of the largest immune organs of the body [85]. The use of human milk and early enteral nutrition are important for reducing the risk of infections.…”

“…Those include immunoglobulins, cytokines and growth factors, medium-and longchain polyunsaturated free fatty acids, milk oligosaccharides, lactoferrin and lysozyme. The immunomodulatory role of these components is reviewed elsewhere [85]. Human milk provides the gold standard for feeding term infants, while for preterm infants it is routinely supplemented with multi-nutrient fortifiers to provide recommended levels of protein, sodium, chloride, magnesium and other micronutrients necessary to support the hypercatabolic state of prematurity.…”

Complementary Feeding in the Preterm Infants: Summary of Available Macronutrient Intakes and Requirements

“…Maternal breast milk (or human donor milk) is the recommended enteral nutrition for preterm or low birth weight (LBW) infants [19,20] in the first months of life. In addition to macro and micronutrients that were optimized during evolution for digestion and absorption by human infants, maternal breast milk contains numerous immuno-nutrients such as secretory immunoglobulin IgA, lactoferrin, cytokines, enzymes, growth factors, and leucocytes [21]. The nutritional requirements of preterm or LBW infants, particularly very preterm and very low birth weight (VLBW) infants, may not be met by enteral feeding with maternal breast milk alone [19], for this reason breast milk is supplemented with products called "fortifying".…”