Fig. 1
Increase in breath H2 in lactase persistent and lactase non–persistent individuals, who were identified by the genotyping test, after ingestion of (a) lactose (50 g), (b) conventional milk (CON; 750 mL; 37.5 g lactose) and (c) a2 Milk (A2M; 750 mL, 37.5 g lactose). * denotes p < 0.05 between LNP and LP. The cut-off value calculated from the ROC curve (Youden index) following ingestion of lactose, CON milk and A2M (79 ppm, 21 ppm and 13 ppm, respectively) is represented by a solid horizontal line for LP and LNP individuals for all three substrates (p < 0.001 each, respectively using Mann-Whitney U test). Group medians and 95% confidence intervals are denoted across data points