Pyruvate is the end product of glycolysis. When individuals are supplemented with pyruvate, the Krebs cycle has been speculated to perform more efficiently. This would lead to an increased rate of ATP production, therefore improving endurance performance.
Also, studies performed on rats have shown that supplementation with pyruvate lowers the animals’ respiratory exchange ratio This would also lead to an increase in performance. Many studies have been done on pyruvate supplementation and weight loss, but few have been performed on pyruvate’s effect on endurance performance.
Human Studies
The effect of pyruvate on endurance was studied by Stanko et al. Ten physically active males substituted 25 g of pyruvate and 75 g of dihydroxyacetone for the same amount of carbohydrate in a standard diet for 7 days. An isocaloric glucose polymer solution was used as a placebo. After supplementation, the subjects performed arm ergometry at 60% until exhaustion. Glycogen levels at rest were significantly higher during the pyruvate trial. Whole arm arteriovenous glucose difference was greater at rest and after 60 minutes of exercise, but did not differ at exhaustion for the supplemented trial versus the placebo. Therefore, glucose extraction was presumed to account for the significant increase in arm endurance during the pyruvate trial versus the placebo.
In a similar study, the effects of pyruvate leg endurance were evaluated by Stanko et al. Eight untrained subjects consumed a high-carbohydrate diet for 7 days with 100 g of polycose (placebo) or dihydroxyacetone (75 g) and pyruvate (25 g) substituted for a portion of carbohydrate. After the diet, cycle ergometer was performed at 70% until exhaustion. Muscle glycogen at rest and exhaustion did not differ between trials. Whole leg arteriovenous glucose difference was greater during the pyruvate trial when compared with the placebo at rest and after 30 minutes of exercise, but not at exhaustion. Estimated total glucose oxidation during exercise was significantly greater in the pyruvate group when compared with the placebo. This led to a significant increase in leg endurance for the pyruvate trial when compared with the placebo.
Conversely, the most recent study on pyruvate was conducted by Morrison et al. Nine recreationally active subjects (8 women and 1 man) ingested 7, 15, or 25 g of pyruvate and were monitored for the next 4 hours. The pyruvate showed no elevation in blood pyruvate, and had no effect on indexes of carbohydrate (blood glucose and lactate) or lipid metabolism (blood glycerol and plasma free fatty acids). Also, in a randomized, double-blind, crossover fashion, 7 g of pyruvate or a placebo were ingested for 1 week by seven, well-trained male cyclists . When the subjects cycled at 74-80% , there were no significant differences in performance between the trials.
An increased production of ATP would be expected after supplementation of pyruvate since endogenous pyruvate leads to the production of ATP Early, high-dose studies showed positive results; however, the most recent study using 7 g showed no improvement in endurance time. More studies on pyruvate supplementation and endurance performance are warranted.
Safety and Toxicity
Supplementation with pyruvate has been shown to have minimal side effects; however, borborygmus (bowel rumbling), flatus, and diarrhea were reported by Stanko et al. Nonetheless, these side effects were mild and usually did not affect performance. Also, in the same studies, vital functions, blood count, and biochemical profiles were not affected.
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