[Hormones and bioactive substances in milk--rudiments or physiologic signals?]

Human milk and milk of lower mammals contains hormones, growth factors, as well as secondary messengers. It can be supposed that in the past this composition secured a better survival for the offspring in a certain phase of development. The question is, what role do the factors play in the physiological development today. They certainly affect the mammary gland at its own right, there is evidence about a positive effect on the intestinal mucosa of infants, even on the regulation of hormonal secretion. Hence, they represent signals sent by the maternal organism and affect the reaction of infants. Whether these effects are physiologically significant in animals and especially in humans still remains to be proved. A very rapidly progressing research promises many interesting and surprising findings in the near future. Objective evaluation of effects of milk composition on the offspring neither allows us to ignore the possibility of negative consequences in postreproductive age, since these signs are not being eliminated by natural selection during evolution.