Preliminary study on DNA damage in non breast-fed infants

BACKGROUND: There are many advantages of human milk for infants, including protection against cancer development and the advantages have been emphasized in several studies. In this study, infants fed by human milk has been compared with those fed by cow's milk concerning DNA damage. METHODS: The level of genetic damage in the peripheral blood lymphocytes of infants who were fed mainly by cow's milk and breast milk has been studied by sister chromatid exchange (SCE) analysis, which is a sensitive measurement of chromosomal damage. Each group consisted of 30 infants, whose ages ranged from 9 to 12 months. RESULTS: A significant increase (P < 0.0001) was found in the frequencies of SCE of infants not breast-fed (n = 30, mean SCE/cell +/- SD: 8.66 +/- 1.15) compared to those who were breast-fed (n = 30, mean SCE/cell +/- SD: 4.93 +/- 0.82). CONCLUSION: To our knowledge, there has been no published study investigating SCE ratio regarding DNA damage in infants not breast-fed. Molecular mechanism of DNA damage caused by the absence of human milk protection is a subject of future investigations.