Bolus tube feeding suppresses food intake and circulating ghrelin concentrations in healthy subjects in a short-term placebo-controlled trial

Abstract

BackgroundPrevious investigations suggest continuous tube feeding (TF) schedules do not suppress appetite and food intake, but bolus TF has been little studied. ObjectiveWe tested the hypothesis that 1) bolus TF does not suppress appetite and food intake and 2) there is no interrelation between food intake and appetite mediators (including ghrelin). DesignA single-blind, placebo-controlled trial within which 6 healthy men [body mass index (in kg/m2): 21.1 ± 1.61] received 3 d of bolus TF (6.93 ± 0.38 MJ/d of 4.18 kJ/mL multinutrient feed). For 2 d before and after TF, placebo boluses (<0.4 MJ/d) were given by tube. Hourly tracking of appetite, weighed measurements of daily ad libitum food intake, and metabolic and hormonal (including ghrelin) measurements were undertaken. ResultsTotal energy intake was significantly increased with bolus TF (18.2 ± 1.86 MJ; P = 0.0005) despite a partial reduction in food intake compared with placebo periods (P = 0.013) and during the TF period (by 15%; P = 0.007). There was little change in hunger and fullness with bolus TF, and within-day temporal patterns did not differ whether TF or placebo was given. Changes in fasting concentrations of ghrelin (1003.6–756.0 pmol/L; P = 0.013) and other mediators (including leptin, insulin, and glucose) were significantly related to subsequent daily food intake (eg, ghrelin: r2 = 0.81, P = 0.022). ConclusionsIn this short-term study, subjects maintained appetite ratings during bolus TF by a significant reduction in food intake and changes in ghrelin and some appetite mediators related to subsequent daily food intake. Longer-term studies are required to fully ascertain the effect of TF on appetite, food intake, and appetite mediators.