Abstract 13390: Metabolomic Changes during Short-term Water-only Fasting: the FEELGOOD Trial
Background: Routine, periodic fasting is associated with a lower risk of coronary artery disease and diabetes in coronary angiography patients, and may reduce weight and alter metabolic risk in obese people. Fasting reportedly extends longevity in animals. This study evaluated the effect of fasting on metabolic profiles among apparently healthy people.
Methods: Individuals (N=30) with no fasting history underwent a 24-hour water-only fast and 24 hours of ad libitum eating in a randomized cross-over trial (clinicaltrials.gov NCT01059760). All participants were free from cardiovascular diseases. Study endpoints included 75 metabolic analytes measured by gas chromatography-mass spectrometry. With the Bonferroni correction, p≤0.000667 was needed for statistical significance (p≤0.05 was suggestively significant).
Results: Participants averaged 43.6±13.5 years of age and 66.7% were female. The 24-hour fasting intervention reduced plasma levels of proline (p=0.00002), tyrosine (p=0.00033), urea (p=0.00034), and galactitol (p=0.00058) compared to the eating day. Overall, 29 factors had p≤0.05 (the expected type I error rate at p≤0.05 for 75 hypothesis tests is 4 false positives), including 16 amino acids (all were reduced by fasting) and 6 fatty acids (all were increased by fasting). Among participants randomized to fast the first 24 hours (n=16), 48-hour levels had returned to baseline for all 29 factors except for suggestively significant lower final values of pyruvate (p=0.014), glutamic acid (p=0.025), and tryptophan (p=0.028).
Conclusion: A 24-hour fasting intervention reduced plasma levels of two amino acids (proline, tyrosine), and metabolomics literature connects lower proline and tyrosine with lower insulin resistance, better cognitive function, and less depression. The other findings confirm the known utilization of urea in the natriuresis of fasting (via excretion of nitrogen) that may lower blood pressure and that, during fasting, glucose is stored as galactose such that galactitol production is limited and fatty acids are used for energy. Changes in these four plus potentially 25 other metabolites suggest a beneficial health impact, which along with the potential to reduce insulin resistance warrants further study of fasting.
Author Disclosures: B.D. Horne: None. J.E. Cox: None. R. Miao: None. J.B. Muhlestein: None. A.R. Butler: None. H.T. May: None. J.F. Carlquist: None. J.L. Anderson: None.
- © 2014 by American Heart Association, Inc.