U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

PubAg

Main content area

Breath carbon stable isotope ratios identify changes in energy balance and substrate utilization in humans

Author:
L. D. Whigham, D. E. Butz, L. K. Johnson, D. A. Schoeller, D. H. Abbott, W. P. Porter, M. E. Cook
Source:
International Journal of Obesity 2014 v.38 no.9 pp. 1248-1250
ISSN:
0307-0565
Subject:
analysis of variance, biomarkers, breakfast, breathing, dinner, energy intake, humans, low calorie diet, lunch, spectroscopy, stable isotopes, volunteers, weight loss
Abstract:
Rapid detection of shifts in substrate utilization and energy balance would provide a compelling biofeedback tool for individuals attempting weight loss. As a proof of concept, we tested whether the natural abundance of exhaled carbon stable isotope ratios (breath δ(13)C) reflects shifts between negative and positive energy balance. Volunteers (n = 5) consumed a 40% energy-restricted diet for 6 days followed by 50% excess on day 7. Breath was sampled immediately before and 1 h and 2 h after breakfast, lunch and dinner. Exhaled breath δ(13)C values were measured by cavity ring-down spectroscopy. Using repeated measures analysis of variance (ANOVA) followed by Dunnett’s contrasts, pre-breakfast breath values on days 2–6 were compared with day 1, and postprandial day 7 time points were compared with pre-breakfast day 7. Energy restriction diminished pre-breakfast breath δ(13)C by day 3 (P<0.05). On day 7, increased energy intake was first detected immediately before dinner (−23.8 ± 0.6 vs −21.9 ± 0.7‰, P = 0.002 (means ± s.d.)), and breath δ(13)C remained elevated at least 2 h post dinner. In conclusion, when shifting between negative and positive energy balance, breath δ(13)C showed anticipated isotopic changes. Although additional research is needed to determine specificity and repeatability, this method may provide a biomarker for marked increases in caloric intake.
Agid:
61407
Handle:
10113/61407