Xanthurenic acid is a metabolite that is measured in urine to assess the body's metabolism of tryptophan, an essential amino acid involved in numerous biological processes, including the synthesis of serotonin and niacin. Elevated levels of xanthurenic acid in the urine can indicate a deficiency in vitamin B6, which is a crucial cofactor in the proper metabolism of tryptophan. When vitamin B6 is insufficient, the body’s ability to convert tryptophan into its beneficial end products is impaired, leading to an accumulation of intermediate metabolites like xanthurenic acid. This marker can also provide insights into potential disruptions in glucose metabolism and immune function, as abnormal levels have been associated with conditions such as diabetes and autoimmune diseases. Monitoring xanthurenic acid levels can thus be an important aspect of understanding overall health, particularly in relation to nutritional status and metabolic functions.
References:
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- Ciorba MA. Kynurenine pathway metabolites: relevant to vitamin B-6 deficiency and beyond. Am J Clin Nutri. 2013;98(4):863-864.
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- Linkswiler H. Biochemical and Physiological Changes in Vitamin B6 Deficiency. Am J Clin Nutr. 1967;20(6):547-557.
- Luhby AL, Brin M, Gordon M, Davis P, Murphy M, Spiegel H. Vitamin B6 metabolism in users of oral contraceptive agents. I. Abnormal urinary xanthurenic acid excretion and its correction by pyridoxine. Am J Clin Nutr. 1971;24(6):684-693.
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- Yess N, Price JM, Brown RR, Swan PB, Linkswiler H. Vitamin B6 Depletion in Man: Urinary Excretion of Tryptophan Metabolites. J Nutr. 1964;84(3):229-236.
Xanthurenic Acid
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