Riboflavin Levels in Maternal Milk: The Influence of Vitamin B₂ Status during the Third Trimester of Pregnancy

Abstract

Objective: The aim of the present investigation was to study the relationship between riboflavin status during the third trimester of pregnancy and levels of this vitamin in transition milk (days 13 to 14 of lactation) and mature 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 during the third trimester was determined by recording the consumption of foods over five days and by registering the quantities provided by dietary supplements. Riboflavin status during this stage of pregnancy was determined via the measurement of the activation of erythrocyte glutathione reductase (EGR) by flavine adenine dinucleotide (FAD). Milk riboflavin levels were determined by fluorometry.

Results: Those subjects with riboflavin intakes below recommended (1.6 mg/day) (Group L) showed lower consumption of milk products (305.2 ±88.5 g/day) 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 seen only in two H subjects. Transition and mature milk riboflavin levels were significantly higher in H subjects (948.1 ±700.1 nmol/L for transition 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 milk). Subjects with α-EGR coefficients over 1.2 in the third trimester showed significantly lower mature milk riboflavin levels (704.1 ±241.8 nmol/L) than did subjects with more satisfactory α-EGR coefficients (996.4 ±302.9 nmol/L).

Conclusion: The influence of maternal vitamin B₂ status during pregnancy on breast milk riboflavin levels was confirmed.

• riboflavin intake
• pregnancy
• lactation
• α-EGR
• riboflavin in milk

This work was supported by grants of the Fondo de Investigaciones Sanitarias de la Seguridad Social (FISss) (Spain) (Ref. 92/1181).