The relationship between dietary vitamin A intake and the levels of sialic acid in the breast milk of lactating women.

Sialic acid (SA) is an important nutrient but few studies have examined the link between dietary intake and breast milk sialic acid. The purpose of this observational study was to assess the potential relationship between human breast milk sialic acid levels and dietary nutrition intake 40 d postpartum. The study population included 90 healthy women who were lactating. Human breast milk SA concentrations were measured using fluorescence detector-high performance liquid chromatography (HPLC-FLD) analysis and nutritional intake was estimated by a computerized validated food frequency questionnaire. SA in human breast milk was bound to free oligosaccharides (82.35%), protein (15.27%) and free sialic acid (2.37%). The findings of this study indicate that subjects with higher milk SA levels showed statistically higher levels of vitamin A compared with subjects with lower SA levels (423.48±172.29 vs. 602.22±126.46 μg/d, p=0.000). In addition, there was a certain association (standardized coefficients=0.713; p=0.000) between breast milk SA and vitamin A intake in healthy young subjects. This study demonstrated that dietary vitamin A intake has a certain relationship with breast milk SA concentrations. This may be attributed to the influence of vitamin A on sialic acid glycoprotein and sialic acid mucopolysaccharide in the human body or the common food sources for vitamin A and sialic acid. Additional study is required to further investigate this relationship.