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

Abstract

Background: Previous investigations suggest continuous tube feeding (TF) schedules do not suppress appetite and food intake, but bolus TF has been little studied. Objective: We 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). Design: A 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. Results: Total 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). Conclusions: In 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. © 2008 American Society for Nutrition.