Improved training tolerance by supplementation with alpha-keto acids in untrained young adults: a randomized, double-blind, placebo-controlled trial

Journal Title (Medline/Pubmed accepted abbreviation): J. Int. Soc. Sports Nutr.
Year: 2012
Volume: 9
First page: 37
doi: 10.1186/1550-2783-9-37
Summary of background and research design:
Background: Accumulation of ammonia during exercise may contribute to fatigue.  α-Keto analogs of amino acids are converted to amino acids in the body with the use of an ammonia functional group, thereby reducing the concentration of ammonia in the cell.  α-Ketoglutarate and branched chain keto acids are two α-keto analog supplements that are currently promoted to aid in sports performance.

Hypothesis: Consumption of keto-analogs of amino acids will increase exercise tolerance, strength and endurance from exercise, reduce physical and mental stress, and improve recovery

Subjects:  Healthy males who do not exercise regularly and who are active less than 2 hours per week, age about 19-32 y

Experimental design: randomized, double-blind, placebo-controlled

- α-Ketoglutarate- 0.2 g/kg body weight/day of a mixture of sodium α-ketoglutarate and calcium α-ketoglutarate
- Branched chain keto acids – 0.2 g/kg body weight/day of a mixture of sodium α-ketoisocaproate, calcium α-ketoisovalerate, and calcium α-ketomethylvalerate
- Control – equivalent amounts of sodium, calcium, and calories with the calories provided by glucose

Protocol: The participants were first evaluated for general health parameters and athletic ability.  They were then randomized to one of the three groups and consumed their assigned supplement for five weeks.  They were also enrolled in an intense training regimen that included aerobic and anaerobic exercises and was designed to achieve an “over-reaching” training level.  After one week, blood samples were collected to assure general health was not compromised by the supplement.  After four weeks on the supplement, they were assessed for physical performance.  Training included a 30 minute run at an intensity that was based on their previously determined individual anaerobic threshold followed by 3 × 3 minute sprints at maximal effort.  After a one week recovery (no exercise), the participants completed the same exercise tests.  During the 5 week experiment, the participants completed recovery-stress questionnaires that inquired about stress and recovery perceptions and related activities.
Summary of research findings: 
  • No negative side effects were reported by participants or assessed by the experimenters during the study.
  • Diet was comparable among groups.
  • Training times for endurance and sprint exercises were similar for all groups for weeks 1 and 2.  From the third week on, those in the control group could not complete the assigned workout routines, but participants in the α-ketoglutarate and branched chain keto acid groups could.  Consequently, they partook in a significantly greater training volume than the control group.
  • VO2max and performance assessed at the individual anaerobic threshold (PIAT, as calculated by power output and blood lactate concentrations measured during the VO2max assessment) increased for all groups during the experiment with no difference between groups.  However, maximum power output (Pmax) increased significantly only among the participants in the α-ketoglutarate group compared to those in the control group, suggesting improved work efficiency.
  • After the one week recovery, those in the α-ketoglutarate and branched chain keto acid groups exhibited significantly greater muscle function as assessed by an isometric unilateral maximum torque of their quadriceps compared to the control group.
  • As reported on the questionnaires, stress did not increase in the α-ketoglutarate or branched chain keto acid groups during the course of the experiment.  However, stress levels were significantly greater in the control group at week 3.  Emotional exhaustion mirrored this trend, though was significantly lower before training in the α-ketoglutarate group.

Key practice applications: Supplementation with branched chain keto acids or α-ketoglutarate improved tolerance to training and enabled untrained participants to perform and maintain high levels of intense exercise for 4 weeks.  Therefore, strength and endurance was augmented in many regards.  This may especially be helpful to individuals just beginning an intense exercise workout, or perhaps those who suddenly increase their workload (example an intense summer camp or boot camp).

Key search terms for this article (5-7 terms): α-ketoglutarate, branched chain acids, beginning training, starting an exercise program
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