Published online by Cambridge University Press: 28 February 2007
While being underweight or stunted is recognized as an important risk factor for increased prevalence and severity of infection and high mortality rates, there is increasing evidence for an independent role for micronutrient deficiency. Improving vitamin A status reduces mortality among older infants and young children and reduces pregnancy-related mortality; it also reduces the prevalence of severe illness and clinic attendance among children. Improving Zn status reduces morbidity from diarrhoeal and respiratory infection. Treatment of established infection with vitamin A is effective in measles-associated complications, but is not as useful in the majority of diarrhoeal or respiratory syndromes. Zn supplements, however, have significant benefit on the clinical outcome of diarrhoeal and respiratory infections. Concerns that Fe supplements might increase morbidity if given in malarious populations appear to be decreasing, in the light of new studies on Fe supplements showing improved haemoglobin without an increase in morbidity. Breast-feeding, well known to protect against diarrhoea, is also important in protecting against respiratory infection, especially in the young infant. Transmission of human immunodeficiency virus (HIV) in breast milk is recognized, but new data showing reduced transmission in infants who receive exclusive breast-feeding rather than mixed feeding reinforces the importance of promoting this practice in areas where environmental contamination precludes the safe use of other infant feeding regimens. The presence of subclinical mastitis, now recognized to occur in approximately 20 % of mothers in several developing countries, has been shown to increase the concentration of HIV in breast milk. Preliminary findings suggest that the prevalence of subclinical mastitis is reduced by dietary supplements containing antioxidants. Governments and international agencies now have a strong scientific basis to be much more active and innovative in the introduction of focused nutrition interventions especially micronutrients, for the control of infection.