Evaluation of retinol levels in human colostrum in two samples collected at an interval of 24 hours.

OBJECTIVE To evaluate retinol concentration in colostrum samples collected with a 24 hour interval. METHOD Colostrum was collected from 24 recently-delivered mothers at two points in time, 0 hours (T0) and 24 hours later (T24), and a pooled sample of colostrum from T0 and T24 was also analyzed. Fat content was determined by creamatocrit, and retinol assayed by high performance liquid chromatography. RESULTS When expressed in terms of volume of milk (microg/dL), retinol levels varied across T0, T24 and the pooled sample: 94.9+/-58.9; 129+/-78.6 and 111.9+/-60.4 microg/dL, respectively. However, when expressed with relation to fat content (microg/g), no significant difference was observed. CONCLUSIONS Retinol assayed in colostrum from a single sample should not be used as an indicator of vitamin A nutritional status, due to the great variation between samples collected at different times. It is suggested that results be expressed per gram of fat, in order to minimize variations resulting from the volume of milk.