Patients with
rheumatoid arthritis have subnormal
vitamin B6 status, both quantitatively and functionally. Abnormal
vitamin B6 status in
rheumatoid arthritis has been associated with spontaneous
tumor necrosis factor (
TNF)-alpha production and markers of
inflammation, including
C-reactive protein and erythrocyte sedimentation rate. Impaired
vitamin B6 status could be a result of
inflammation, and these patients may have higher demand for
vitamin B6. The aim of this study was to determine if daily supplementation with 50 mg of
pyridoxine for 30 days can correct the static and/or the functional abnormalities of
vitamin B6 status seen in patients with
rheumatoid arthritis, and further investigate if
pyridoxine supplementation has any effects on the pro-inflammatory
cytokine TNF-alpha or
IL-6 production of
arthritis. This was a double-blinded, placebo-controlled study involving patients with
rheumatoid arthritis with plasma
pyridoxal 5'-phosphate below the 25th percentile of the Framingham Heart Cohort Study.
Vitamin B6 status was assessed via plasma and erythrocyte
pyridoxal 5'-phosphate concentrations, the erythrocyte
aspartate aminotransferase activity coefficient (alphaEAST), net
homocysteine increase in response to a
methionine load test (DeltatHcy), and 24 h urinary
xanthurenic acid (XA) excretion in response to a
tryptophan load test. Urinary
4-pyridoxic acid (4-PA) was measured to examine the impact of
pyridoxine treatment on
vitamin B6 excretion in these patients. Pro-inflammatory
cytokine (TNF-alpha and IL-6) production,
C-reactive protein levels and the erythrocyte sedimentation rate before and after supplementation were also examined.
Pyridoxine supplementation significantly improved plasma and erythrocyte
pyridoxal 5'-phosphate concentrations, erythrocyte alphaEAST, urinary 4-PA, and XA excretion. These improvements were apparent regardless of baseline B6 levels.
Pyridoxine supplementation also showed a trend (p < 0.09) towards a reduction in post-
methionine load DeltatHcy. Supplementation did not affect pro-inflammatory
cytokine production. Although
pyridoxine supplementation did not suppress pro-inflammatory
cytokine production in patients with
rheumatoid arthritis, the suboptimal
vitamin B6 status seen in
rheumatoid arthritis can be corrected by 50
mg pyridoxine supplementation for 30 days. Data from the present study suggest that patients with
rheumatoid arthritis may have higher requirements for
vitamin B6 than those in a normal healthy population.