2 Polychlorinated Biphenyls and Levels of Polyunsaturated Fatty Acids in Human Milk

Abstract

Background: Environmental contaminants such as persistent organic chlorines may contaminate human milk and negatively affect neural development. To what extent organic chlorines might influence levels of polyunsaturated fatty acids (PUFA) in milk has not been investigated yet. In this study we have investigated whether concentration of polychlorinated biphenyls (PCBs) may be associated with PUFA levels in human milk.Methods: Subjects: 25 healthy women (mean [SD, range] age 33 [6, 23–42] y., pre-pregnancy body mass index <25kg/m2, 88%, smoking during pregnancy, 24%, primiparous, 32%, who had been living in Milan or surrounding areas for at least 20 years and who delivered full term singleton infants participated in the study. Mothers exclusively breastfed for at least 4 months. Samples from colostrum, the first 2 days after delivery, and mature breast milk after 1 and 3 months were collected. The samples were analyzed for PCB 105, 118, 138, 153, 156 and 180, and for C18:2 n-6 (linoleic acid), C18:3 n-3 (alinolenic acid), C20:4 n-6 (arachidonic acid), C20:5 n-3 (eicosapentaenoic acid), C22:6 n-3 (docosahexaenoic acid) by means of gas-chromatographic techniques.Results: The concentrations of all examined contaminants were highest in colostral milk and then declined (P<0.001). PUFA levels did not show a definite smooth trend, except C20:4 n-6 and C22:6 n-3 whose concentrations declined (P<0.001). The concentrations of PCBs in milk were associated with mother's age, correlation coefficient (r) 0.57 < r <0.86, P <0.001. No significant association was found between levels of PUFAs and mother's age, P >0.14. No significant association was found of PCBs with PUFAs in human milk: colostrum, −0.16 < r < 0.25, P > 0.19; 1 month, −0.34 < r < 0.20, P0.10; 3 months, −0.27 < r <0.33, P0.11.Conclusion: Within the population of this study, no evident association was found between concentration of PCBs and PUFAs, in human milk.