PYY and dyspepsia: Although postprandial PYY levels are reported to be reduced (Pilichiewicz et al., 2008) or unchanged (Witte et al., 2016) compared to healthy control, there is a correlation between postprandial PYY levels and feelings of fullness, suggesting a potential role of this hormone in early satiety in functional dyspepsia (Witte et al., 2016).