Maternal nutrition and breast feeding.

In this short review we will first summarize current theories relating to maternal nutritional needs during human lactation, then deal with dietary situations where theory and experimental findings differ. In fact such a divergence occurs most of the time, both in affluent countries and especially in the Third World. We will then consider the various hypotheses which are currently being tested in an attempt to rationalize this complex but crucially important enigma. These hypotheses suggest that the mother can 'adapt' both physiologically and behaviourally in order to protect the adequate nutrition of her baby. Finally we will discuss the health significance of what happens when the mother's ability to accommodate the nutritional stresses of pregnancy and lactation fails. Although we have been asked to deal just with lactation, from time to time it will also become necessary to consider events occurring during pregnancy in order to place the nutritional stresses of lactation within a rational biological perspective. Whilst in the medical world, parturition tends to be a watershed event which divides one clinical specialty from another, in nutritional terms its main significance is merely that the mother switches feeding her baby from one part of her anatomy to another. In so far as her nutritional requirements are concerned pregnancy and lactation are part of the same continuum.