Long-term effects of calorie or protein restriction on serum IGF-1 and IGFBP-3 concentration in humans

What Was Tested

The paper reports a study of IGF-1 LR3, published as a randomized controlled trial.

However, the long-term effects of CR with adequate nutrition on circulating IGF-1 levels in humans are unknown.

Here the researchers report data from two long-term CR studies (1 and 6 years) showing that severe CR without malnutrition did not change IGF-1 and IGF-1 : IGFBP-3 ratio levels in humans.

Who Took Part

The study group was 3 volunteers.

The age groups tagged for this paper are middle-aged adults, both men and women.

How the Study Was Run

The design is described as randomized.

Random assignment meant chance, not the researchers, decided who got IGF-1 LR3 and who got the comparison, which limits bias.

A time span of 3 weeks appears in the methods.

What Was Measured

However, the long-term effects of CR with adequate nutrition on circulating IGF-1 levels in humans are unknown.

Here the researchers report data from two long-term CR studies (1 and 6 years) showing that severe CR without malnutrition did not change IGF-1 and IGF-1 : IGFBP-3 ratio levels in humans.

Topics PubMed links to this paper include Aging, Caloric Restriction, Dietary Proteins, Energy Intake, Insulin-Like Growth Factor Binding Protein 3, Insulin-Like Growth Factor Binding Proteins and Insulin-Like Growth Factor I.

What This Means in Plain Language

The paper is a randomized study of IGF-1 LR3 in 3 volunteers over 3 weeks.

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.

The publication is from 2008 (Aging cell), a journal based in England.

More context: the IGF-1 LR3 compound page, all human trials.