Q. I’m hearing about carnosine as an “anti-aging” supplement. What else is it good for and can we get enough of it in our diet?
A. Carnosine (technically L-carnosine) is a combination of two amino acids, L-alanine and L-histidine. It is found most abundantly in skeletal and heart muscle and in the brain. The histidine and alanine that make up carnosine are not joined with the usual “peptide” bond, and thus supplementing with histidine and alanine separately does not have the same effect provided by supplements of carnosine.
When automated amino acid analysis was first developed, the presence of carnosine in urine was thought to be an indication of poor digestion. Now we know more. Human research on carnosine is still sparse, done mostly in Russia and Japan, but the bulk of the information we have about carnosine from animal studies demonstrates it to be a good antioxidant, especially effective at protecting against radiation damage. Probably because of this antioxidant activity, it appears to promote wound-healing and improve heart function.
Less predictably, it has been clinically successful in improving the behavior of autistic children. Because of the extraordinary variety of symptoms in children labeled as autistic, the term Autistic Spectrum Disorders is now favored to describe the changes in language and behavior that are characteristic of autism. Autistic children typically have large gaps in their communication skills. A pediatric neurologist by the name of Dr. Michael Chez recently reported that carnosine supplements benefited 90% of the 1,000 children who used the supplement under his direction. Although Dr. Chez found that carnosine was virtually nontoxic, he warns that too high of a dose may over-stimulate some children, resulting in increased irritability, hyperactivity, or insomnia, often already a problem for autistic children.
Human clinical studies also reveal that carnosine can aid in eradicating Helicobacter pylori, the infectious organism that is closely linked to peptic ulcers and possibly stomach cancer. Sixty patients suffering from stomach problems and diagnosed with H. pylori infection were given antibiotics alone or antibiotics plus the zinc salt of carnosine. The group receiving zinc carnosinate had a 94% eradication rate of H. pylori compared to 77% for the group receiving antibiotics alone.
Perhaps the most important action of carnosine is its ability to prevent attachment of glucose to protein, forming abnormal proteins. This process inevitably takes place as we age, but carnosine “takes the hit” of glucose attachment, and the end product of this reaction does not promote aging.
As with other antioxidants, carnosine should be used as part of a team of nutrients. For example, when vitamin E was given along with carnosine, levels of both substances were higher in cardiac muscle than when either was used alone.
Dietary sources of carnosine consist primarily of the high-protein foods such as beef, pork, poultry, and fish. Carnosine supplements are not cheap but are not prohibitively expensive (about $1 a day), and since it is found only in animal products, vegetarians might consider a supplement.
The precise biological role of carnosine has not yet been completely revealed, but numerous animal studies promise a bright future when all the facts are available.
This article appears in May 30 • 2003.