Fig. 2

Alkaline phosphatase activity of breast milk as a function of time. Average ALP units in breast milk samples obtained in postnatal days 2–5, week 2 (days 8–13), week 3–4 (days 17–22) and week 6–7 (days 40–49). Error bars represent standard deviation and n is sample size. All coefficients in the model are statistically significant at the p < 0.001 level using a mixed-effects regression model in which model coefficients represent the difference between the ALP activity in the first week and ALP activity in week 2, week 3–4, and week 6–7