Effect of vitamin B-6 deficiency on fasting plasma homocysteine concentrations

Joshua W. Miller, Judy D. Ribaya-Mercado, Robert M. Russell, Douglas C. Shepard, Frank D. Morrow, Elizabeth F. Cochary, James A. Sadowski, Stanley N. Gershoff, Jacob Selhub

Research output: Contribution to journalArticle

117 Scopus citations

Abstract

The catabolism of homocysteine through cystathionine synthesis requires pyridoxal-5′-phosphate, thus the effect of vitamin B-6 deficiency on plasma homocysteine concentrations was evaluated. Total fasting plasma homocysteine concentrations were measured in 11 elderly subjects aged 64.4 ± 1.7 y (x̄ ± SE) who consumed a vitamin B-6-deficient diet for ≤ 20 d. Only 1 of the 11 subjects was found to have elevated homocysteine concentrations even though all subjects exhibited high urinary xanthurenic acid concentrations after a tryptophan load, a measure indicative of vitamin B-6 deficiency. In a supporting study, fasting plasma homocysteine concentrations were measured in 3- and 23-mo-old rats fed vitamin B-6-deficient diets and were compared with those of vitamin B-6-replete, pair-fed controls. There was no difference in homocysteine concentrations between deficient and pair-fed animals after 6 wk of the dietary regimen for either age group; after 9 wk a modest elevation was observed in the 3-mo-old deficient rats whereas no difference was observed for the 23-mo-old rats. It is concluded that fasting plasma homocysteine concentrations are not initially elevated in vitamin B-6 deficiency and therefore fasting plasma homocysteine concentrations are not a good indicator of vitamin B-6 status.

Original languageEnglish (US)
Pages (from-to)1154-1160
Number of pages7
JournalAmerican Journal of Clinical Nutrition
Volume55
Issue number6
StatePublished - Jun 1992
Externally publishedYes

Keywords

  • Homocysteine
  • Homocysteinemia
  • Humans
  • Rats
  • Vitamin B-6 deficiency

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

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    Miller, J. W., Ribaya-Mercado, J. D., Russell, R. M., Shepard, D. C., Morrow, F. D., Cochary, E. F., Sadowski, J. A., Gershoff, S. N., & Selhub, J. (1992). Effect of vitamin B-6 deficiency on fasting plasma homocysteine concentrations. American Journal of Clinical Nutrition, 55(6), 1154-1160.