taurine

Taurine is an organic compound classified as 2-aminoethanesulfonic acid. It is a sulfur-containing non-proteinogenic amino acid that is abundant in animal tissues, particularly heart, brain, retina, and skeletal muscle. Its chemical formula is C2H7NO3S. Taurine is not incorporated into proteins.

Biochemistry and metabolism: In humans, taurine is partly synthesized endogenously from cysteine via cysteine dioxygenase and cysteine sulfinic acid decarboxylase to hypotaurine, which is oxidized to taurine; the synthesis uses vitamin B6 as a cofactor. Taurine can also be obtained from the diet, especially meat and seafood, and is excreted in urine largely unchanged.

Functions: Taurine contributes to the conjugation of bile acids (taurocholate, and related taurine-conjugated bile salts) in the liver, aiding fat digestion and absorption. It also acts in osmoregulation, antioxidant protection, calcium signaling, neuromodulation, and membrane stabilization. In the retina and heart it has supportive roles; in infants, taurine is important for development.

Dietary sources and uses: Foods of animal origin supply taurine; many infant formulas and some energy drinks include added taurine. It is used in medical nutrition products, including parenteral nutrition.

Safety and regulation: Taurine is considered safe for consumption within typical dietary ranges; there is no human requirement established as an essential nutrient. High-dose supplements are generally well tolerated, though data on long-term effects are limited and products containing taurine should be consumed in moderation, particularly with caffeine-containing beverages.