Trans Fatty Acids Content in Breast Milk as a Marker of Their Short-Term Intake Within the Breastfeeding Mother's Diet: A Single-Participant Pilot Study.

Introduction: Breast milk is the best food for a growing infant during the first 6 months of life. The presence of trans fatty acids (TFAs) in breast milk can interfere with the synthesis of long-chain polyunsaturated fatty acids (LC-PUFAs), increasing the risk of developing, among other issues, asthma or atopic dermatitis. TFAs are not synthesised de novo in the human body. Their content in breast milk may be a good marker of short-term dietary intake of these compounds by breastfeeding mothers. However, the literature shows differences in the assessment of the relationship between dietary TFAs intake and TFAs content in breast milk. Furthermore, the decrease in the TFAs content in food observed recently seems to make it impossible to use Craig-Schmidt's formula to estimate the TFAs content in the diet or in breast milk. The aim of this study was to confirm the possibility of using TFAs content in breast milk as a marker of their short-term intake within the breastfeeding mother's diet, together with an attempt at preliminary quantitative determination of the relationship between these parameters. Materials: The study material was collected from a single breastfeeding mother and included 10 breast milk samples and 10 samples of daily food rations reconstructed based on the 24 h food consumption survey. Methods: The content of fatty acids, including TFAs, was determined by gas chromatography-mass spectrometry (GC-MS). Results: The TFAs content in the whole-day mother's diet and in 100 mL of breast milk ranged from 0.11 to 0.54 g/day and from 0.02 to 0.07 g, respectively. A strong statistically significant (p < 0.05) positive correlation between these parameters was found. Equations for an exploratory linear relationship between the TFAs content in a breastfeeding mother's diet and the concentration of these fatty acids in breast milk have been developed. Due to the small number of samples, these data should be interpreted very cautiously and validated in a larger cohort. Conclusions: This single-participant pilot study suggests that TFAs content in breast milk may be a marker of the dietary intake of these compounds from the previous day. It seems that the dietary habits of breastfeeding mothers of twins are a significant factor influencing the composition of breast milk and, consequently, the nutritional quality of breastfed infants.