L-Carnosine is found throughout the body, but it is particularly abundant in those cells that are long-lived, such as nerve cells (neurons) and muscle cells (myocytes). Chemically, it is a dipeptide (a molecule consisting of two amino acids) constructed from beta-alanine and L-histidine, hence its chemical name - beta-alanyl-L-histidine. L-carnosine, as is true of the antioxidant enzyme superoxide dismutase (SOD), is one of a handful of compounds that are present in tissues at levels that correlate strongly with the life spans of animal species. Muscle levels of L-carnosine decline approximately 63% between the ages of 10 and 70. However, brain levels of L-carnosine remain high in comparison with the levels found in most other tissues. Scientists have speculated that this may be one reason that brain function remains stable into old age despite the brain's dependence upon glucose for energy metabolism and the unusually high ratio of fructose to glucose in the brain.
The ultimate test of cellular rejuvenation is the way in which an animal ages. A Russian study tested the effect of carnosine on life span and indicators of senescence in age-accelerated mice by giving half the mice carnosine in their drinking water starting at two months of age. At the conclusion of the study, the mice given carnosine were about twice as likely to reach the “ripe old age" of 12 months as were untreated mice.
In vitro experiments confirm that L-carnosine provides protection against a wide range of reactive oxygen species including the hydroxyl, superoxide, and peroxyl radicals as well as singlet oxygen.* Such a breadth of protection makes L-carnosine one of the most efficient of free radical scavengers and antioxidants available to the body.* Furthermore, L-carnosine also appears to chelate excess metals that can be catalysts for oxidative damage and to help regulate the pH (acid-base) of tissues.*
The proteins that make-up bodily tissues can readily be damaged as a result of oxidation and interactions with sugars or other types of aldehydes. The major forms of undesirable protein modifications include free radical damage, carbonylation (attachment of carbonyl groups to proteins), and advanced glycation end product (AGE) formation. All of these changes can lead to dysfunction in structural proteins and enzymes. Glycation refers to the oxidation and conjugation of protein by glucose. In chemistry, this type of reactivity is sometimes referred to as non-enzymatic “browning" (i. e. the Maillard reaction). The result is a complex set of reactions between glucose, or another reducing sugar molecule, and the amino groups of some amino acids in the protein. In fact, this is the process that occurs every time meats are “browned" during cooking.
An overlapping type of damage to proteins is the mere attachment of extraneous carbonyl groups. Some authorities estimate that in older adults, one third of all proteins may become carbonylated leading to a decline in a variety of cellular functions. L-Carnosine has been shown to “sacrifice" itself as a substitute victim to glycating agents, thus sparing the proteins and membranes which otherwise would have been the inadvertent targets of glycation.* Furthermore, there is some evidence that L-carnosine may react with and remove the carbonyl groups of glycated proteins in some instances.*
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
