Abstract
Background
The study investigated the concentration of IgA, IgM and IgG in colostrum, transitional and mature milk and the effect of parity, age, BMI and family income on secreted immunoglobulin contents of human milk.
Methods
Sequential samples of colostrum, transitional and mature milk were collected from 38 women. Enzymelinked immunosorbent assay was used to analyse the immunoglobulin concentrations.
Results
The study revealed that IgA was the dominant immunoglobulin and mean concentration in colostrum, transitional and mature milk was 5.92 ± 1.50 g/L, 3.85 ± 0.64 g/L and 3.72 ± 0.68 g/L, respectively. Both IgA and IgM levels of colostrum decreased significantly in both transitional (P = 0.000) and mature milk (P = 0.000), while the concentration of IgG rises significantly in them (colostrum vs. transitional milk, P = 0.000; and colostrum vs. mature milk P = 0.011). While maternal age, BMI and family income had no significant influence on the immunoglobulin levels at different stages of lactation, parity showed significant influence on IgG (P = 0.03) and IgM (P = 0.05) levels of transitional milk and IgA level of colostrum (P = 0.05).
Conclusion
The findings suggest that immunoglobulin composition in breast milk is strongly associated with stage of lactation and is likely to be more susceptible to parity than BMI and socioeconomic characteristics.