Breast-feeding and host defense

Abstract

Breast-feeding constitutes the most reliable means of increasing infant survival, as demonstrated by the successful perpetuation of humankind through millions of years of exclusive dependence on human milk. Breast milk was the only source of nutrition for young human infants until cattle were domesticated, which occurred in several geographic regions around 10,000 BC. The study of feeding practices in traditional societies in Latin America, Africa, and Asia offers an insight into man's struggle in ancient times. Three major problems are evident: (a) maternal malnutrition as a consequence of excessive physical exertion, infectious diseases and poor diets, which often result in secretion of suboptimal volumes of milk: (b) deficient village diet generally based on cereals, legumes, and tubers as the main source of weaning. The child must adapt to bulky and often contaminated village foods through a protracted and perilous process that begins at 3-6 months of age; (c) excessive infections, particularly of the gastrointestinal and respiratory tracts, which increase abruptly with the onset of weaning, and often result in reduced food consumption, nutrient wastage, loss of body muscle mass, growth retardation, acute malnutrition and death These events likely forced ancient societies to search for supplements or substitutes for mother's milk. Their experience with breast-feeding and weaning led to the genesis of traditions, beliefs and taboos regarding supplementary feeding, some of which still prevail in modern times [1, 2]. Contemporary traditional societies suffer from additional complicating factors, such as (a) the availability of a wide variety of commercial infant formulas, and (b) the evolution of society toward a 'western' model affected by urban life, mother-infant separation at birth and stress. The result in societies undergoing transition has been a dramatic increase in failure to breast-feed and of premature weaning, with ensuing increase in risk of diarrheal diseases, malnutrition and death