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The effect of galactose supplementation on endurance cycling performance.
Eur J Clin Nutr. 2009 Feb; 63(2):209-14.EJ

Abstract

OBJECTIVES

This study tested the hypothesis that supplementation with galactose before and during endurance exercise would spare carbohydrate (CHO), optimize fat utilization and improve performance compared with a typical sports drink formulation.

SUBJECTS

Nine well-trained cyclists undertook three trials, each consisting of 120 min at 65 VO(2max) followed immediately by a set work, self-paced time trial (TT). Three treatments, allocated as a randomized balanced design, consisted of the following: (a) 8% (w/w) solution of galactose (Gal); (b) 8% solution of 50% galactose/50% glucose (Gluc/Gal); and (c) 8% solution of 80% glucose/20% fructose (Gluc/Fru). These were consumed as 0.67 g CHO per kg body wt 45-min pre-exercise; 1.0 g CHO per kg body wt per h for the first 120 min of exercise; 0.33 g CHO per kg body wt during the TT. Blood samples were collected before and during exercise; respiratory gas samples were collected only during fixed workload exercise.

RESULTS

Mean TT power output was significantly less in Gal compared with Gluc/Gal (P=0.030). Blood glucose and insulin concentrations were lower, and free fatty acids higher in Gal compared with Gluc/Gal and Gluc/Fru. Respiratory exchange ratio was not significantly different between trials.

CONCLUSIONS

Ingestion of an 8% galactose-only solution (12.5 ml per kg body wt per h) is detrimental to endurance performance compared with equivalent volumes of iso-osmotic solutions containing 50% galactose/50% glucose or 80% glucose/20% fructose. This may reflect the inability of the liver to convert galactose into glucose at a rate required to support strenuous exercise intensity.

Authors+Show Affiliations

Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand. S.Stannard@massey.ac.nzNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17928803

Citation

Stannard, S R., et al. "The Effect of Galactose Supplementation On Endurance Cycling Performance." European Journal of Clinical Nutrition, vol. 63, no. 2, 2009, pp. 209-14.
Stannard SR, Hawke EJ, Schnell N. The effect of galactose supplementation on endurance cycling performance. Eur J Clin Nutr. 2009;63(2):209-14.
Stannard, S. R., Hawke, E. J., & Schnell, N. (2009). The effect of galactose supplementation on endurance cycling performance. European Journal of Clinical Nutrition, 63(2), 209-14.
Stannard SR, Hawke EJ, Schnell N. The Effect of Galactose Supplementation On Endurance Cycling Performance. Eur J Clin Nutr. 2009;63(2):209-14. PubMed PMID: 17928803.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The effect of galactose supplementation on endurance cycling performance. AU - Stannard,S R, AU - Hawke,E J, AU - Schnell,N, Y1 - 2007/10/10/ PY - 2007/10/12/pubmed PY - 2009/4/17/medline PY - 2007/10/12/entrez SP - 209 EP - 14 JF - European journal of clinical nutrition JO - Eur J Clin Nutr VL - 63 IS - 2 N2 - OBJECTIVES: This study tested the hypothesis that supplementation with galactose before and during endurance exercise would spare carbohydrate (CHO), optimize fat utilization and improve performance compared with a typical sports drink formulation. SUBJECTS: Nine well-trained cyclists undertook three trials, each consisting of 120 min at 65 VO(2max) followed immediately by a set work, self-paced time trial (TT). Three treatments, allocated as a randomized balanced design, consisted of the following: (a) 8% (w/w) solution of galactose (Gal); (b) 8% solution of 50% galactose/50% glucose (Gluc/Gal); and (c) 8% solution of 80% glucose/20% fructose (Gluc/Fru). These were consumed as 0.67 g CHO per kg body wt 45-min pre-exercise; 1.0 g CHO per kg body wt per h for the first 120 min of exercise; 0.33 g CHO per kg body wt during the TT. Blood samples were collected before and during exercise; respiratory gas samples were collected only during fixed workload exercise. RESULTS: Mean TT power output was significantly less in Gal compared with Gluc/Gal (P=0.030). Blood glucose and insulin concentrations were lower, and free fatty acids higher in Gal compared with Gluc/Gal and Gluc/Fru. Respiratory exchange ratio was not significantly different between trials. CONCLUSIONS: Ingestion of an 8% galactose-only solution (12.5 ml per kg body wt per h) is detrimental to endurance performance compared with equivalent volumes of iso-osmotic solutions containing 50% galactose/50% glucose or 80% glucose/20% fructose. This may reflect the inability of the liver to convert galactose into glucose at a rate required to support strenuous exercise intensity. SN - 1476-5640 UR - https://www.unboundmedicine.com/medline/citation/17928803/The_effect_of_galactose_supplementation_on_endurance_cycling_performance_ L2 - http://dx.doi.org/10.1038/sj.ejcn.1602924 DB - PRIME DP - Unbound Medicine ER -