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Randomized Controlled Trial
. 2016 Feb;15(1):22-7.
doi: 10.1111/acel.12400. Epub 2015 Oct 6.

Effects of 2-year Calorie Restriction on Circulating Levels of IGF-1, IGF-binding Proteins and Cortisol in Nonobese Men and Women: A Randomized Clinical Trial

Free PMC article
Randomized Controlled Trial

Effects of 2-year Calorie Restriction on Circulating Levels of IGF-1, IGF-binding Proteins and Cortisol in Nonobese Men and Women: A Randomized Clinical Trial

Luigi Fontana et al. Aging Cell. .
Free PMC article


Young-onset calorie restriction (CR) in rodents decreases serum IGF-1 concentration and increases serum corticosterone levels, which have been hypothesized to play major roles in mediating its anticancer and anti-aging effects. However, little is known on the effects of CR on the IGF-1 system and cortisol in humans. To test the sustained effects of CR on these key hormonal adaptations, we performed a multicenter randomized trial of a 2-year 25% CR intervention in 218 nonobese (body mass index between 22 and 27.8 kg m(-2) ) young and middle-aged (20-50 years age range) men and women. Average CR during the first 6 months was 19.5 ± 0.8% and 9.1 ± 0.7% over the next 18 months of the study. Weight loss averaged 7.6 ± 0.3 kg over the 2-years period of which 71% was fat mass loss (P < 0.0001). Average CR during the CR caused a significant 21% increase in serum IGFBP-1 and a 42% reduction in IGF-1:IGFBP-1 ratio at 2 years (P < 0.008), but did not change IGF-1 and IGF-1:IGFBP-3 ratio levels. Serum cortisol concentrations were slightly but significantly increased by CR at 1 year only (P = 0.003). Calorie restriction had no effect on serum concentrations of PDGF-AB and TGFβ-1. We conclude, on the basis of the present and previous findings, that, in contrast to rodents, humans do not respond to CR with a decrease in serum IGF-1 concentration or with a sustained and biological relevant increase in serum cortisol. However, long-term CR in humans significantly and persistently increases serum IGFBP-1 concentration.

Keywords: IGF-1; IGFBP-1; calorie restriction; cancer; cortisol; weight loss.


Figure 1
Figure 1
CONSORT diagram.

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