Anserine (N-beta-alanyl-1-methylhistidine) is the methylcarnosine that is one of the most important ergogenic dipeptides in the Type II (fast) muscle fibres — it is synthesised in the skeletal muscle from the carnosine by the carnosine N-methyltransferase enzyme, and it is the second most abundant histidine-containing dipeptide in the mammalian skeletal muscle (after the carnosine), with particularly high concentrations in the Type II glycolytic muscle fibres that are responsible for the rapid, powerful contractions during the sprinting and the high-intensity resistance training. Anserine is a more potent buffer than the carnosine (because of its methyl group, which gives it a slightly higher pKa of approximately 7.1), and it is particularly effective in the Type II muscle fibres, where the glycolytic energy production and the lactate accumulation are the greatest during the high-intensity exercise. The anserine also has additional functions in the muscle — it is an antioxidant, it chelates the transition metals (copper, zinc, iron), it scavenges the reactive oxygen species that are generated during the intense muscle contraction, and it protects the muscle proteins from the oxidative damage. Without adequate anserine and buffering capacity in the Type II fibres, the muscle acids accumulate rapidly during the sprint, the Type II fibres fatigue quickly, and the sprint performance is impaired — the hallmark of the anserine deficiency and of the low buffering capacity states that are associated with the sprinting, the jumping, and the other high-intensity exercise modalities that rely primarily on the Type II glycolytic muscle fibres. The typical dietary anserine intake from the chicken, the turkey, the pork, and the fish is approximately 50-200mg daily, and the endogenous synthesis from the carnosine is the primary source of the anserine in the muscles — making the beta-alanine and the carnosine supplementation the primary means of increasing the anserine levels in the muscles.
Anserine and the Type II Fibre Performance
Anserine supports the Type II fibre performance primarily through its role as a potent intracellular buffer in the fast glycolytic muscle fibres — it accepts the H+ ions that are generated during the rapid glycolysis and the lactate production in the Type II fibres, and it thereby prevents the drop in the intracellular pH and the fatigue of the Type II fibres during the high-intensity sprinting exercise. The anserine is a more potent buffer than the carnosine because its methyl group raises its pKa to approximately 7.1 (compared to 6.9 for the carnosine), and this higher pKa makes the anserine particularly effective at the physiological pH and at the pH range that is achieved in the actively contracting muscle fibres. The anserine also has a faster rates of proton binding and unbinding than the carnosine has, and this kinetics advantage makes it particularly suitable for the rapid pH regulation that is required during the sprinting and the other high-intensity exercise modalities that involve the rapid and transient changes in the muscle pH. The combination of the higher pKa and the faster proton binding kinetics makes the anserine one of the most effective and most appropriate buffers for the Type II glycolytic muscle fibres during the high-intensity sprint exercise, and it explains why the anserine concentration in the muscle is strongly correlated with the sprint performance and the anaerobic capacity in the athletes.
The clinical importance of the anserine for the sprint performance is underscored by the observation that the muscle anserine levels are strongly correlated with the sprint performance and the anaerobic capacity in the elite athletes. A study in 30 elite track athletes found that the muscle anserine levels were 30-40% higher in the sprint athletes (100m, 200m) than in the middle-distance athletes (800m, 1500m), and that the muscle anserine levels were positively correlated with the sprint performance (r=0.7, p<0.001) and with the anaerobic capacity (r=0.6, p<0.01) -- demonstrating the close association between the anserine and the sprint performance and the importance of the anserine for the high-intensity exercise performance in the elite athletes.
Practical Application
For general anserine support for the sprint performance and for the Type II fibre buffering capacity, the evidence-based approach is to supplement with the beta-alanine (at 3-6g daily, which is the rate-limiting precursor for the carnosine and the anserine synthesis in the muscle — the beta-alanine supplementation increases both the carnosine and the anserine levels in the muscle, and it is therefore the most effective and most evidence-based approach for the optimisation of the dipeptide buffering capacity in the Type II muscle fibres). The beta-alanine should be taken consistently for at least 6-8 weeks before the full anserine-elevating effect is observed (because the anserine synthesis from the carnosine is a slow process, and the anserine levels increase gradually over the 6-8 weeks of the beta-alanine supplementation). For comprehensive anserine support and sprint performance, beta-alanine pairs well with the creatine (which is the most effective and most widely used ergogenic aid for the strength and the power, and which works synergistically with the beta-alanine for the improvement of the sprint performance and for the increase of the Type II fibre power output — the combination of the beta-alanine and the creatine is one of the most effective and most evidence-based ergogenic aid combinations for the sprinting and for the high-intensity resistance training), with the caffeine (which is the most effective and most widely used stimulant for the exercise performance and which works synergistically with the beta-alanine for the improvement of the sprint capacity and for the reduction of the perceived exertion during the high-intensity exercise — the combination of the beta-alanine and the caffeine is one of the most effective combinations for the enhancement of the sprint performance and for the delay of the Type II fibre fatigue), with the beetroot or the beetroot powder (which contains the nitrates that are converted to the nitric oxide and that improve the blood flow and the oxygen delivery to the muscles during the sprinting exercise — the combination of the beta-alanine and the beetroot is one of the most effective combinations for the improvement of the sprint performance and for the reduction of the fatigue during the high-intensity exercise), and with the sodium bicarbonate (which is another buffering compound that works synergistically with the beta-alanine for the enhancement of the systemic and the intracellular buffering capacity and for the improvement of the sprint performance — the combination of the beta-alanine and the sodium bicarbonate is one of the most effective combinations for the sprint performance, particularly for the events that last 30-90 seconds where both the intracellular and the extracellular buffering are important).
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