|L-carnosine is a dipeptide composed of the covalently bonded amino acids alanine and histidine and is found in the brain, heart, skin, muscles, kidneys and stomach. High carnosine levels are associated with an increase in physical performance especially
anaerobic performance. Carnosine has been reported through studies, revealed that carnosine administration can, indeed, benefit the immune responsiveness. Carnosine is found in relatively high concentrations in several body tissues - most notably in skeletal muscle, heart muscle, and brain. Dietary sources of preformed carnosine include meat and poultry and fish. Carnosine deficiency may occur in severe protein deficiency and in certain severe genetic disorders characterized by inborn errors in amino acid metabolism. The average daily intake of carnosine from foods is probably in the range of 50-250mg (based on a diet containing at least one serving, 3-4 ounces, of beef, pork or chicken).
Carnosine is best known for its ability to buffer lactic acid in muscle tissue and for its multiple antioxidant capabilities. Carnosine is the water-soluble counterpart to vitamin E in protecting cell membranes from oxidative damage. Carnosine is one of the most important and potent natural antioxidant agents which act as universal antioxidants both in the lipid phase of cellular and biological membranes and in the aqueous environment protecting lipids and water-soluble molecules like proteins (including enzymes), DNA and other essential macromolecules from oxidative damage mediated by reactive oxygen species and lipid peroxides. Carnosine, in addition to antioxidant and oxygen free-radical scavenging activities, also reacts with deleterious aldehydes to protect susceptible macromolecules. Carnosine also regulates zinc and copper concentrations in nerve cells, helping to prevent overstimulation by these neuroactive minerals. Carnosine eye drops have been shown to be 100% effective in cases of primary senile cataract and 80% effective in cases of mature senile cataracts.
Carnosine participates in a variety of physiological processes. Carnosine interacts with several free radical species including singlet oxygen, hydrogen peroxide, and both peroxyl and hydroxyl radicals. Carnosine is able to inhibit radical-induced cellular damage induced by iron, copper and zinc. Carnosine also appears to play a role in activating the enzymes responsible for generating muscle contractions as well as serving as an intramuscular buffering agent to retard accumulation of lactic acid. Carnosine’s use as a dietary supplement is generally slanted toward sports nutrition. Its possible roles in delaying fatigue, reducing stress, buffering acid buildup, wound healing, muscle contraction, and oxidative protection position carnosine as both an ergogenic aid and as a general tonic. Carnosine may act as a neurotransmitter (chemical messenger in the nervous system), modulator of enzyme activities, and chelator of heavy metals (i.e., a substance that binds heavy metals, possibly reducing their toxicity). Carnosine and complexes containing carnosine have been described in skin care compositions and to promote wound healing.
L-carnosine supports healthy aging and cellular rejuvenation by its effects on two mechanisms: glycosylation and free radical damage. Glycosylation is the oxidation of protiens by glucose resulting in cross-linking of proteins and which is implicated in loss of cell function, genome integrity and accelerated aging. Carnosine, with its known anti-glycating properties, may provide an anti-aging effect on fibroblast material by inhibiting cross-linking of glycoxidized proteins. Carnosine inhibits formation of MDA-induced protein-associated advanced glycosylation end products (AGEs) and formation of DNA-protein cross-links induced by acetaldehyde and formaldehyde. Carnosine is reactive as an anti-glycating agent with aldehydes and ketones, that is compounds containing carbonyl groups capable of blocking carbonylated proteins, that form in step b., describe above, and thus prevent the formation of detrimental AGE's. During the aging process glycated end products of bonding between protein material and sugar molecules naturally leads to formation of deep wrinkles in the skin that are particularly visible in normally exposed areas such as the face. Carnosine prevents, reduces and can reverse the formation of such glycated end products and also breaks the protein-sugar bonds to enable actual reversal of skin wrinkles.