Riboflavin levels in maternal milk: The influence of vitamin B-2 status during the third trimester of pregnancy

Objective: The aim of the present investigation was to study the relationsh ip between riboflavin status during the third trimester of pregnancy and le vels of this vitamin in transition milk (days 13 to 14 of lactation) and ma ture milk (day 40 of lactation). Methods: The pregnancies and lactation periods of 57 healthy women between 18 and 35 years of age (27 +/- 3.7 years) were monitored, vitamin intake du ring the third trimester was determined by recording the consumption of foo ds over five days and by registering the quantities provided by dietary sup plements. Riboflavin status during this stage of pregnancy was determined v ia the measurement of the activation of erythrocyte glutathione reductase ( EGR) by flavine adenine dinucleotide (FAD). Milk riboflavin levels were det ermined by fluorometry. Results: Those subjects with riboflavin intakes below recommended (1.6 mg/d ay) (Group L) showed lower consumption of milk products (305.2 +/- 88.5 g/d ay) than did those with greater intakes (Group H) (507.9 +/- 137.2 g/day). The consumption of riboflavin containing supplements was very low and was s een only in two H subjects. Transition and mature milk riboflavin levels we re significantly higher in H subjects (948.1 +/- 700.1 nmol/L for transitio n milk and 993.8 +/- 436.6 nmol/L for mature milk) than L subjects (574.9 /- 258.7 nmol/L for transition milk and 725.4 +/- 254.3 nmol/L for mature m ilk). Subjects with alpha-EGR coefficients over 1.2 in the third trimester showed significantly lower mature milk riboflavin levels (704.1 +/- 241.8 n mol/L) than did subjects with more satisfactory alpha-EGR coefficients (996 .4 +/- 302.9 nmol/L). Conclusion: The influence of maternal vitamin B-2 status during pregnancy o n breast milk riboflavin levels was confirmed.