scientist E. S. Severin showed as early as in 1953 that carnosine significantly
contributes to the physicochemical buffering in skeletal muscles, which maintains
acid-base balance when a large quantity of H(+) is produced in association with
lactic acid accumulation during high-intensity exercise. Carnosine accounts for
up to 30% of the buffering capacity of the body. Recent studies confirm that increased
muscle carnosine concentrations lead to increased intramuscular hydrogen ion (H+)
buffering capacity (Dunnet and Harris 1999, Dunnet et al. 2002) and that preexercise
carnosine regulates the intracellular pH (pH(I)) of oxidative and glycolytic muscle
fibers (Damon et al. 2003).
In fact, carnosine supplementation keeps the pH in the muscle almost neutral.
We all know that when lactic acid in strenuous work accumulates in our muscles,
and the pH falls, we get tired and ultimately exhausted. As muscle carnosine concentration
reduces with age, also our muscular strength and endurance decline as we age.
Supplementation with carnosine seems to restore the muscular carnosine concentration
and thus increase the strength, endurance and speed up the recovery.
Fig. 1. Carnosine (30 nM) increases significantly
the amount of calcium (Ca2+) liberated from the muscle. Black columns = carnosine
supplementation, white columns = without carnosine (the the pH falls and closes
the calcium channels (see Rubtsov 2001).
Carnosine helps the function of the calcium pump in the sarcoplasmic reticulum in the muscle cells and keeps the calcium channels open. In the lack of carnosine, the pump ceases to function and the channels close, as a result of acidity, lipid peroxidation and accumulation of malondialdehyde (MDA).
Carnosine fights all these harmful reactions, and it seems to be an ideal physiologic supplement in sports. Carnosine is not considered as a doping substance.
In sports and body building carnosine is involved in the detoxification
pathway of reactive aldehydes from lipid peroxidation generated in skeletal muscle
during physical endurance (Aldini et al. 2002a,b). Hence carnosine protects the
skeletal muscles from injury, increases muscle strength and endurance and speed
up recovery after strenuous exercise, as suggested by scientific tests.
Japanese investigators examined the relations among the skeletal muscle
carnosine concentration, fiber-type distribution, and high-intensity exercise
performance amoung 11 healthy men. Muscle biopsy samples were taken from the vastus
lateralis at rest and the carnosine concentration was determined by the use of
an amino acid autoanalyzer. The fiber-type distribution was determined by the
staining intensity of myosin adenosinetriphosphatase. The high-intensity exercise
performance was assessed by the use of 30 second maximal cycle ergometer sprinting.
A significant correlation was demonstrated between the carnosine concentration
and the type IIX fiber composition. The carnosine concentration was significantly
correlated with the mean power per body mass during the 30-s sprinting. When dividing
the sprinting into 6 phases (0-5, 6-10, 11-15, 16-20, 21-25, 26-30 s), significant
correlations were observed between the carnosine concentration and the mean power
per body mass of the final 2 phases. These results indicated that the carnosine
concentration could be an important factor in determining the high-intensity exercise
carnosine prevents muscular injuries and speed up recovery times in sports. One
of the explanations is that high-intensity performance causes oxidative stress
in the musculature, which in turn eats up the carnosine stores. The free radicals
cause lipid peroxidation as well as carbonylation of proteins and phospholipids.
As stated before, carnosine combats these reactions, provided, that there is enough
of it in the muscles.
Figure 2. Carnosine inhibits effectively accumulation of lactate, as result of
hypoxia, in rat brain. Hypoxia was experimentally induced by ligating four arteries.
1=rats supplemented with carnosine, 2=controls. The columns indicate the lactate
concentration before ligature (a) and thereafter (b) 35-45 minutes, (c) 90-100
min and (d) 150-170 min (Stvolinsky ja Dobrota 2000).
Research suggests that the minimum quantity is 2.5 mM in order to halt lipid peroxidation and 1 mM to stop carbonylation. In one study rats were fed carnosine for 13 months, and it was noted that the carnosine concentration in their skeletal muscles increased significantly, and at the same time lipidperoxidation and carbonylation diminished. This relevant study proved that carnosine indeed, in physiological circumstances prevents lipid peroxidation and protein carbonylation (Nagasawa ym 2001).
Another study on rats indicated that the carnosine concentration in the soleus muscle increased 5-fold and the histidine content 2-fold in 8 weeks, when the rats were given 1.8 % carnosine in the food. There is reason to believe that the same occurs in man. Therefore carnosine seems to be the ideal supplement for athletes.