Maternal, Perinatal and Pediatric Nutrition
Objective: It remains unclear whether breast milk fructose levels are affected by mothers’ intake of fructose during lactation. The primary aim of this study was to determine the acute effects of consuming a high-fructose corn syrup (HFCS)-sweetened beverage on changes in breast milk fructose, glucose, and lactose among lactating women. The secondary aim was to test moderation by pre-pregnancy obesity status. Methods: Forty-one exclusively breastfeeding mothers (54% obese) participated in a crossover study at 6 weeks postpartum. Mothers provided a fasted baseline breast milk sample, and were randomized to consume either a commercially available HFCS-sweetened beverage (65 grams of sugar) or artificially sweetened control beverage (0 grams of sugar) a minimum of three days apart. At each session, mothers pumped a complete breast milk expression every hour for 6 consecutive hours. Breast milk sugars were measured using LC-MS/MS. Results: Baseline concentrations of breast milk fructose, glucose, and lactose were 5.0 ± 1.3 µg/mL, 0.6 ± 0.3 mg/mL, and 6.8 ± 1.6 g/dL, respectively. Changes over time in breast milk sugars were significant only for fructose (treatment x time, P<0.01). Post hoc comparisons showed that the HFCS-sweetened beverage vs. control beverage increased breast milk fructose levels at 120 minutes (8.8 ± 2.1 vs. 5.3 ± 1.9 µg/mL), 180 minutes (9.4 ± 1.9 vs. 5.2 ± 2.2 µg/mL), 240 minutes (7.8 ± 1.7 vs. 5.1 ± 1.9 µg/mL), and 300 minutes (6.9 ± 1.4 vs. 4.9 ± 1.9 µg/mL) (all P<0.05). There was no moderation by pre-pregnancy obesity status. Conclusions: Our data suggest that consumption of an HFCS-sweetened beverage increased breast milk fructose levels, which were sustained up to 5 hours post-consumption.