Vitamin B6 concentrations in patients with chronic liver disease and hepatocellular carcinoma.

Vitamin B6 concentrations in patients with chronic liver disease and hepatocellular carcinoma Vitamin B6 is the generic term for three closely related and interconvertible compounds. Most of the vitamin B6 obtained from the diet is rapidly converted by the liver to its active coenzyme, pyridoxal-5-phosphate, which has a central role in the metabolism of amino acids. Patients with chronic liver disease are commonly deficient in pyridoxal-5-phosphate, and this may be due to decreased conversion of vitamin B6 to pyridoxal-5-phosphate, although increased breakdown of pyridoxal-5-phosphate'2 or decreased intake or poor absorption of dietary vitamin B6 may be responsible. Comment The normal concentrations of total pyridoxal in most of the patients with cirrhosis suggest that deficient intake and poor absorption of vitamin B6 are not the major cause of the deficiency of pyridoxal-5-phosphate in such patients found in this and other studies. This deficiency may be due either to failure of hepatic conversion of vitamin B6 or to enhanced degradation of pyridoxal-5-phosphate. Although in this study there was no relation between a fetoprotein concentrations and pyridoxal-5-phosphate deficiency, experimental studies have shown that dietary deprivation ofvitamin B6 may lead to increased a fetoprotein concentrations and preneoplastic nodules in baboons.4 The possibility that vitamin B6 deficiency is a risk factor for the development of hepatocellular carcinoma in cirrhosis cannot be excluded, particularly as seven ofthe patients had lower concentrations ofpyridoxal-5-phosphate than any normal subject.