The nutrient rich lumen of the small intestine provides a favourable environment for microbial cell growth. Secretion of defensins from Paneth cells constitutes a key source of antimicrobial peptide activity in the crypt lumen.¹ In addition, defensins also recruit the adaptive immune system.^2,3 Chronic disease, major surgery, trauma, or malnutrition results in immune compromise and can increase the risk of infection and sepsis.⁴ Several clinical studies have demonstrated that patients fed an immune enhancing formula had significantly fewer infectious complications, needed less antibiotics, and had a shorter hospital stay than patients fed standard diets.⁵ However, the mechanism by which these formulas bolster the immune system is unclear.

We hypothesised that a nutrient enriched diet bolsters the immune system by upregulating defensin expression in the jejunum and ileum, the two parts where cryptdins (mouse intestinal defensins) are highly expressed. To study the effect of an immune enhancing diet (Perative; Ross Products, Abbott Laboratories, USA) on intestinal defensin expression, …