Suppression of Energy Intake by Intragastric l-Tryptophan in Lean and Obese Men: Relations with Appetite Perceptions and Circulating Cholecystokinin and Tryptophan

What Was Tested

The paper reports a study of Cholecystokinin (CCK), published as a randomized controlled trial.

The researchers evaluated the effects of intragastric Trp on energy intake (primary outcome) and their potential mechanisms, pre- and postmeal, in lean men and those with obesity.

Why It Was Studied

The underlying mechanisms, including appetite, plasma cholecystokinin (CCK), tryptophan (Trp), and the ratio of Trp to large neutral amino acids (Trp:LNAAs ratio), and whether responses differ in lean and obese individuals, are uncertain.

Who Took Part

The abstract describes 13 men taking part.

By PubMed's age tags, the people studied were adults, men only.

Data were analyzed using maximum likelihood mixed-effects models, with treatment, group, and treatment-by-group interaction as fixed effects.

How the Study Was Run

The researchers set it up as a randomized and double-blind study.

Because people in this Cholecystokinin (CCK) study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

Neither the men nor the staff measuring them knew who was on Cholecystokinin (CCK), so expectations could not easily colour the readings.

Energy intake from the buffet-meal, hunger, fullness, and plasma CCK and amino acid concentrations were measured in response to Trp alone and for 2 h postmeal.

What Was Measured

Topics PubMed links to this paper include Appetite, Cholecystokinin, Energy Intake, Obesity and Tryptophan.

The authors tagged it with the keywords amino acids, food intake, fullness, hunger and tryptophan to large neutral amino acids ratio.

What This Means in Plain Language

The paper is a randomized and double-blind study of Cholecystokinin (CCK) in 13 men.

With fewer than 40 people, it is a small study, so it is better read as an early signal for further research than as a settled answer.

Its findings take up roughly 6 sentences of the abstract and are left out here on purpose; the source paper is the place to read them.

The publication is from 2021 (The Journal of nutrition), a journal based in United States.

More context: the Cholecystokinin (CCK) compound page, all human trials.