Abstract
This review focuses on the specific effects of nutrients on the intestinal immune system. The intestinal immune system possesses a number of special characteristics different from those of the systemic immune system, which are summarised in this report. Although some of these characteristics are well known, there is a big gap regarding the specific mechanisms that regulate immunity at intestinal level with respect to the systemic immunity. Because of that, during the last years, there is an increasing interest in elucidating the inner mechanisms that regulate the intestinal immune function, as well as how specific nutrients influence that function. We have reviewed this topic with special emphasis on how human milk and its components influence the development of the intestinal immunity in early infancy compared with formula-fed infants. Interactions between nutrients and the intestinal microflora have also been reviewed. Some micronutrients, which are present in human milk and in most of foods, are capable of influencing immune functioning at very low concentrations. The specific action of these micronutrients on some parameters of the intestinal immunity as well as the potential mechanisms of action promoted by them have been considered more in detail. However, few data exist on how other specific nutrients, namely protein and non-protein compounds, lipids, carbohydrates, and others, such as mineral and vitamins, influence the intestinal immunity. Further research in these areas is highly recommended.