A food supplement widely used by athletes plays a significant role in the production of carnosine in skeletal muscle. Carnosine helps eliminate reactive aldehydes, which can compromise the structure and function of DNA and proteins.
The action of the supplement, an amino acid called beta-alanine, was observed for the first time in skeletal muscle by Brazilian researchers. The results are published in the journal Redox Biology.
The phenomenon was observed when beta-alanine was administered to athletes after a bout of strenuous exercise. Carnosine binds to aldehydes such as acrolein to form adducts (addition products), whose presence shows that carnosine is combating these toxic substances.
A previous study showed that carnosine-acrolein adducts were found in the urine of adult nonsmokers, but exactly where they were formed was unknown.
This latest study was conducted by researchers who are affiliated with the University of São Paulo’s School of Physical Education and Sports (EEFE-USP) and Chemistry Institute (IQ-USP), collaborating via the Center for Research on Redox Processes in Biomedicine (Redoxome), one of the Research, Innovation and Dissemination Centers (RIDCs) funded by FAPESP.
“The carnosine found in the athletes’ muscles demonstrates the beneficial effect of physical exercise, since it causes the elimination of toxic substances,” said Marisa Helena Gennari de Medeiros, Full Professor at IQ-USP and last author of the paper.
The researchers took samples of the vastus lateralis (outer thigh) muscle from 14 cyclists before and after a 28-day period during which the athletes took a beta-alanine supplement or a placebo daily in a double-blind experiment (neither the researchers nor the volunteers knew whether they were taking the supplement or the placebo).
The muscle samples were collected after four bouts of Wingate high-intensity intermittent cycling, a well-known physical education test.
“The athletes pedaled all out for 30 seconds in each bout and recovered for three minutes between bouts,” said Guilherme Giannini Artioli, a professor at EEFE-USP and principal investigator for the project under which the experiment was conducted, with a Young Investigator grant from FAPESP.
The samples were collected shortly after the high-intensity exercise and analyzed using a specific ultrasensitive methodology based on high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). The methodology was developed by Medeiros’s group, which in this case used it for the precision detection of carnosine and carnosine-aldehyde adducts in muscle tissue.
The analysis showed that beta-alanine increased muscle carnosine levels by some 50% compared with those measured before the supplement was taken. Moreover, a significant increase in carnosine-acrolein adduct was found in post-supplement muscle tissue sampled after performance of the exercise protocol.
“The interesting point is that neither exercise alone nor supplementation alone increased the formation of adducts. This shows that carnosine sequesters acrolein in skeletal muscle, which is important to detoxify the reactive aldehydes produced during exercise,” Medeiros told Agência FAPESP.
Because reactive aldehydes damage the structure and function of DNA and protein by forming these adducts, the results not only show that the supplement genuinely benefited the athletes involved but also point to possible treatments for conditions and diseases in which oxidative stress is abnormally elevated, such as cardiovascular disorders, atherosclerosis, Parkinson’s and Alzheimer’s.
“We can now think about the action of carnosine not only in the physiological model, meaning physical exercise, but also in pathological models in which levels of reactive aldehydes increase, as an effect of smoking, pollution, diabetes, or other situations involving oxidative stress. It’s worth exploring this therapeutic potential,” Artioli said.
The group plans to study the effects of beta-alanine supplementation in older people.
“As the population ages, it’s important to have resources that contribute to improved muscle strength for seniors. In addition, carnosine could be effective in combating chronic pain associated with a buildup of aldehydes,” Medeiros said.