Journal Title (Medline/Pubmed accepted abbreviation): Br. J. Nutr.
Page numbers: 1438-1442
doi (if applicable): 10.1017/S0007114510002321
Summary of Background and Research Design
Background:;Ammonia (NH3) and ammonium (NH4+) are produced during exercise as a result of the breakdown of amino acids for energy or the deamination of AMP. Ammonia compounds are toxic and excreted as ammonium in the urine. However, during exercise, production exceeds the rate of elimination and blood ammonia levels correlate highly with central and peripheral fatigue. Keto acid analogues of amino acid (keto analogues) can be utilized also to synthesize ATP without the ammonia waste product.
Hypothesis/Research Question:Does supplementation with keto analogues associated with amino acids (KAAA) reduce ammonia production and blood urea levels during resistance exercise? Can this supplement enhance performance and/or accelerate recovery?
Subjects:48 x 12-wk old Wistar rats
Experimental Design:randomized block, 4 groups
Treatments and protocol:Groups:
1. KAAA supplementation (0.1 g Ketosteril® in 0.5 mL water (0.3 g/kg). Ketosteril contains α-keto analogues of : (Measures below are per tablet; the weight of the tablet was not disclosed).
- Isoleucine- 335 mg
- Leucine- 505 mg
- Phenylalanine- 430 mg
- Valine- 340 mg
- α-hydroxy analogue of methionine- 295 mg
- l-lysine acetate- 75 mg
- l-threonine- 265 mg
- l-tryptophan- 115 mg
- l-histidine- 190 mg
- l-tyrosine- 150 mg
2. Exercise- 0.5 mL of 0.9% sodium chloride was provided 1 hr before exercise. The rats were acclimated to the exercise device by attaching them every day for 6 days before the actual test. The apparatus involved a hindlimb squat-like simulation for rats. One day before the test, the rats’ individual 1 repetition maximum (1RM) was determined. On the day of the experiment, 50 reps were performed at 75% of their 1RM. Blood samples were acquired immediately before and immediately after exercise and analyzed for urea, urate, glucose, lactate, ammonia, and creatinine.
3. KAAA supplementation and exercise
4. No KAAA supplementation, no exercise (Control)
Summary of Research Findings
- Supplementation increased ammonia levels at rest 40%. However, after exercise, ammonia levels were markedly lower in supplemented animals than nonsupplemented (100% increase in nonsupplemented rats and 40% in supplemented rats).
- KAAA supplementation increased glucose levels in resting animals 10%. Glycemia after exercise was not affected by glucose supplementation.
- Blood lactate was increased 100% in the supplementation group and only 57% in the non-supplemented exercise group.
- Creatinine clearance was more efficient with KAAA supplementation.
Interpretation of findings/Key practice applications:
There is still a lot that is unknown regarding the mechanism and the effectiveness of keto analogues in the performance-related arena. For example, KAAA supplementation attenuated blood ammonia levels during exercise, but they are increased them at rest in this animal model. It is unknown, therefore, if chronic intake of KAAA would be beneficial with regard to serum ammonia levels. More research must be performed before this supplement is recommended.
Limitations of the research:
These authors and others have postulated that ammonia levels in the blood contribute to fatigue. However, there were no data presented in this study as to whether the lowering of blood ammonia level during exercise improved weight lifting performance in the animals.