A report published in the January 2005 issue of the journal Experimental Neurology revealed that the amino acid L-carnitine helps protect the brain of rats from the DNA damage that occurs with aging.
Dr P. A. R. Juliet of Nagoya University in Japan and colleagues gave 4 month old and 24 month old rats 300 milligrams acetyl-L-carnitine per kilogram body weight for 7, 14 and 21 days following which their brain cortex, hippocampus, striatum, hypothalamus and cerebellum were examined for antioxidant enzyme activity, nucleic acid (DNA and RNA) levels, and DNA damage.
Carnitine levels were lower in all brain regions examined in the 24 month old rats than in the 4 month old animals, although longer supplementation with L-carnitine was reflected in increased brain levels of the amino acid in the older animals, which was not observed in the younger rats. Older rats also had lower brain levels of the antioxidant enzymes superoxide dismutase and glutathione peroxidase, as well as lower DNA and RNA levels in the cortex, hippocampus and striatum, however in older rats who received L-carnitine, the researchers found enhanced levels of antioxidants and nucleic acids that increased with duration of the treatment, which again, were not found to be effected by carnitine in the younger rats.
When DNA damage was assessed, it was found to be higher in the older rat brains than in the younger rats, particularly in the cortex, hippocampus and striatum, and carnitine was shown to provide the greatest protection against damage in these areas. L-carnitine did not significantly reduce brain DNA damage in young rats.
The authors propose that L-carnitine provides its neuroprotective effect by promoting energy production, activating a DNA repairing enzyme and enhancing antioxidant status.
