title: Does low serum carnosinase activity favor high-intensity exercise capacity?
abstract: Given the ergogenic properties of β-alanyl-L-histidine (carnosine) in skeletal muscle, it can be hypothesized that elevated levels of circulating carnosine could equally be advantageous for high-intensity exercises. Serum carnosinase (CN1), the enzyme hydrolyzing the dipeptide, is highly active in the human circulation. Consequently, dietary intake of carnosine usually results in rapid degradation upon absorption, yet this is less pronounced in subjects with low CN1 activity. Therefore, acute carnosine supplementation before high-intensity exercise could be ergogenic in these subjects. In a cross-sectional study, we determined plasma CN1 activity and content in 235 subjects, including 154 untrained controls and 45 explosive and 36 middle- to long-distance elite athletes. In a subsequent double-blind, placebo-controlled, crossover study, 12 men performed a cycling capacity test at 110% maximal power output (CCT 110%) following acute carnosine (20 mg/kg body wt) or placebo supplementation. Blood samples were collected to measure CN1 content, carnosine, and acid-base balance. Both male and female explosive athletes had significantly lower CN1 activity (14% and 21% lower, respectively) and content (30% and 33% lower, respectively) than controls. Acute carnosine supplementation resulted only in three subjects in carnosinemia. The CCT 110% performance was not improved after carnosine supplementation, even when accounting for low/high CN1 content. No differences were found in acid-base balance, except for elevated resting bicarbonate following carnosine supplementation and in low CN1 subjects. In conclusion, explosive athletes have lower serum CN1 activity and content compared with untrained controls, possibly resulting from genetic selection. Acute carnosine supplementation does not improve high-intensity performance.
authors.affiliation: Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium;
authors.forename: Audrey
authors.initials: A
authors.lastname: Baguet
authors.forename: Inge
authors.initials: I
authors.lastname: Everaert
authors.forename: Benito
authors.initials: B
authors.lastname: Yard
authors.forename: Verena
authors.initials: V
authors.lastname: Peters
authors.forename: Johannes
authors.initials: J
authors.lastname: Zschocke
authors.forename: Ana
authors.initials: A
authors.lastname: Zutinic
authors.forename: Emile
authors.initials: E
authors.lastname: De Heer
authors.forename: Tomasz
authors.initials: T
authors.lastname: Podgórski
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Domaszewska
authors.forename: Wim
authors.initials: W
authors.lastname: Derave
mesh_terms: D000136:Acid-Base Equilibrium / Q000502:physiology; D000293:Adolescent; D000328:Adult; D001639:Bicarbonates / Q000097:blood; D002336:Carnosine / Q000494:pharmacology; D003124:Colorimetry; D003402:Creatine Kinase / Q000378:metabolism; D018592:Cross-Over Studies; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D004150:Dipeptidases / Q000097:blood*; D004311:Double-Blind Method; D004797:Enzyme-Linked Immunosorbent Assay; D015444:Exercise / Q000502:physiology*; D005260:Female; D005290:Ferric Compounds / Q000097:blood / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D013177:Sports; D017392:Thiobarbituric Acid Reactive Substances; D055815:Young Adult
chemical_list: D001639:Bicarbonates; D005290:Ferric Compounds; D017392:Thiobarbituric Acid Reactive Substances; D002336:Carnosine; D003402:Creatine Kinase; D004150:Dipeptidases; C019673:aminoacyl-histidine dipeptidase
keywords: acute carnosine supplementation; carnosinase activity/content; elite athletes; high-intensity exercise