Regional, socioeconomic, and dietary factors influencing B-vitamins in human milk of urban Chinese lactating women at different lactation stages.

BACKGROUND

Adequate B-vitamins concentrations in human milk are considered to be a prerequisite for healthy development of infants in early life. This study aims to determine the concentrations of B-vitamins in human milk from Chinese women and the relationships between their concentrations and different geographical origin, lactation stages, socioeconomic characteristics, and dietary intake.

METHODS

Human milk was obtained from 443 healthy lactating women from Beijing ( = 150), Suzhou ( = 146), and Guangzhou ( = 147) cities. Thiamine, riboflavin, vitamin B (nicotinamide and nicotinic acid), and vitamin B (pyridoxal, pyridoxine, and pyridoxamine) in human milk were analyzed by high performance liquid chromatography-tandem mass spectrometry. Pantothenic acid, biotin, and folates in human milk were analyzed by microbiological assay. The information from one 24-h dietary recall and socioeconomic characteristics were collected by interview and structured questionnaire, respectively.

RESULTS

B-vitamins concentrations in human milk varied greatly among individuals. The median concentrations of B-vitamins of 5-11 d, 12-30 d, 31-60 d, 61-120 d, and 121-240 d were respectively as follows: thiamine 3.13, 5.07, 4.28, 5.65, 6.28 (μg/100 g); riboflavin 20.8, 20.2, 11.9, 13.6, 15.6 (μg/100 g); vitamin B 194.0, 300.0, 261.0, 212.5, 218.0 (μg/100 g); pantothenic acid 236.5, 291.0, 254.0, 179.0, 189.0 (μg/100 g); vitamin B 6.34, 7.58, 8.60, 9.34, 10.20 (μg/100 g); biotin 0.462, 0.834, 0.606, 0.523, 0.464 (μg/100 g); folates 0.730, 2.390, 2.440, 2.420, 2.330 (μg/100 g). The levels of B-vitamins presented regional differences and varied significantly among different lactation stages. The inversely associations of thiamine, vitamin B, and folates with maternal BMI were found in multivariate analyses ( < 0.05), as well as higher pantothenic acid, folates, and biotin concentrations in lactating women with supplement intake when compared with those without ( < 0.05). Riboflavin concentrations associated with regular exercise was found in multivariate analyses ( < 0.05).

CONCLUSIONS

The present study indicated regional and socioeconomic factors, lactation stage, and supplement intake may influence B-vitamins concentrations of human milk in healthy Chinese mothers. Further studies on accurate and complete analysis of all vitamin forms are crucial for giving a more comprehensive understanding of vitamin status in human milk.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01971671. Registered 13 October 2013.