Taurine deficiency

Taurine deficiency is rare in adult humans but is common in domestic cats, due to poor absorption from tinned catfood. Consequences of taurine deficiency in cats are cardiomyopathy, retinal degradation, reproductive failure in females, developmental abnormalities and impairment of the immune system. It is possible that a chronic deficiency in humans may have similar effects. 

It is not known to what extent taurine may be a dietary essential for human beings. There is little cysteine sulfinic acid decarboxylase activity in the human liver and, like the cat, loading doses of methionine and cysteine do not result in any significant increase in plasma taurine. This may be because cysteine sulfinic acid can also undergo transamination to /3-sulfhydryl pyruvate, which then loses sulfur dioxide nonenzymically to form pyruvate, thus regulating the amount of taurine that is formed from cysteine. There is no evidence of the development of any taurine deficiency disease under normal conditions. 

In children undergoing long-term total parenteral nutrition without taurine supplements, there are changes in the electroretinogram similar to those seen in the taurine-deficient cat, suggesting that there is a requirement for some preformed taurine and that endogenous synthesis may be inadequate. 

It has been suggested that preterm infants may require a dietary source of preformed taurine breast mifk initially contains a high concentration (about 300 /xmol per L), and breast-fed infants maintain a higher plasma concentration of taurine than those fed on formula without added taurine (Chesney et al., 1998). Although mUk from vegan mothers has a low concentration of taurine, and their infants have lower plasma concentrations and urinary excretion of taurine than the infants of omnivore mothers, there is no evidence that (full-term) infants of vegan mothers show any signs of taurine deficiency. 

Acquired alterations on platelet iunction have been detected in cats. Taurine deficient cats have decreased ADP-induced platelet aggregation and release reaction (Welles et al. 1993). C ats with cardiomyopathy and those infected with feline infectious peritonitis have increased platelet aggregation responses (Helenski et al. 1987 Boudreaux et al 1990). 17.6 PIG... 

They become blind- A taurine deficiency results in degeneration of the retinas the tapetum Juddum, a layer of cells behind the retina, degenerptes,... 

The reproductive capacity of iemaJe cats is compromised, A taurine deficiency provokes frequent fetal resorptions and abortions,... 

Other retin d degenerations that may be confused with toxic reactions in the retina of laboratory species include nutritional retinal degeneration due to taurine deficiency in cats and vitamin E deficiency in dogs. 

Moran J, Maar TE, Pasantes-Morales H. Impaired cell volume regulation in taurine deficient cultured astrocytes. Neurochem Res 1994 19 415-420. 

Hayes, K.C., Carey, R.E., and Schmidt, S.Y., 1975, Retinal degeneration associated with taurine deficiency in the cat. Science, 188 949-951. 

The high concentration of taurine in the lens of the kitten remains almost unchanged during taurine deficiency, suggesting an important role for taurine in this organ" ... 

It is clear that only further studies on the uptake, synthesis, content and disposal of taurine in human tissues in a variety of situations and at various ages can confirm or reject the suggestion proposed here, that taurine may be an essential nutrient in Man, and taurine deficiency, therefore, a potential health hazard. 

Gaull, Taurine deficiency in the kitten Exchange and turnover of ( S) taurine in brain, retina and other tissues, J. Nutr. lo8 l -62 (1978). 

To date no adverse clinical signs attributed to taurine deficiency have been identified in human infants fed commercial formulas, although no systematic investigations have been made. There are a number of lines of evidence, however, which suggest that such investigations should be made. 

Cats and kittens fed a synthetic diet containing partially-purified casein as the source of protein become taurine deficient and develop retinal degeneration. This degeneration, which eventually results in blindness, can be prevented or reversed by supplementing these diets with taurine but not by supplementation via ostensible taurine precursors, methionine, cysteine or inorganic sulfate (Hayes et al., 1975a,b Schmidt et al., 1976). 

Taurine deficiency can be created in man under other circumstances. In infants fed total parenteral nutrition, in which the amino acid solution does not contain taurine, the concentration of taurine in the plasma and urine decreases (Rigo and Senterre, 1978). 

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