TABLE 1.
Plasma concentrations of one-carbon metabolites and ratios in OC users vs. nonusers with adequate (PLP = 31–70 nmol/L) and low (PLP ≤30 nmol/L) vitamin B-6 status1
| Adequate vitamin B-6 status |
Low vitamin B-6 status |
|||
| Nonusers (n = 11) | OC users (n = 93) | Nonusers (n = 11) | OC users (n = 18) | |
| PLP,2 nmol/L | 45.7 ± 12.5 | 47.9 ± 11.5 | 20.5 ± 3.75 | 24.7 ± 4.29 |
| Pyridoxal, nmol/L | 7.71 ± 1.53 | 12.1 ± 4.46* | 4.06 ± 1.09 | 7.90 ± 2.61* |
| Pyridoxic acid, nmol/L | 12.2 ± 3.07 | 18.8 ± 7.47* | 4.47 ± 1.17 | 13.4 ± 4.30* |
| Pyridoxine, nmol/L | 0.003 ± 0.007 | 0.02 ± 0.09 | 0.012 ± 0.013 | 0.011 ± 0.032 |
| Cystathionine,3 μmol/L | 0.14 ± 0.03 | 0.12 ± 0.04 | 0.24 ± 0.11 | 0.14 ± 0.10† |
| Homocysteine, μmol/L | 6.22 ± 1.09 | 5.60 ± 1.47 | 6.05 ± 0.88 | 6.75 ± 2.15 |
| Cysteine, μmol/L | 241 ± 36.1 | 235 ± 26.9 | 233 ± 24.1 | 231 ± 31.0 |
| Glutathione, μmol/L | 6.43 ± 1.49 | 3.10 ± 0.83* | 7.29 ± 1.57 | 4.38 ± 1.45* |
| Chol, μmol/L | 7.84 ± 1.23 | 7.47 ± 1.54 | 8.75 ± 1.98 | 7.92 ± 1.73 |
| Bet, μmol/L | 37.8 ± 13.9 | 20.1 ± 5.92* | 40.1 ± 13.3 | 20.3 ± 5.03* |
| DMG, μmol/L | 2.53 ± 0.54 | 2.99 ± 0.93 | 2.38 ± 0.60 | 3.69 ± 3.87 |
| Creatinine, μmol/L | 72.9 ± 14.2 | 69.0 ± 7.59 | 71.2 ± 22.9 | 69.1 ± 10.8 |
| Methionine, μmol/L | 26.5 ± 3.74 | 26.2 ± 4.19 | 27.7 ± 6.95 | 25.5 ± 3.41 |
| Arg, μmol/L | 98.2 ± 21.6 | 74.5 ± 16.4* | 93.0 ± 26.5 | 73.5 ± 13.2 |
| ADMA, μmol/L | 0.75 ± 0.12 | 0.43 ± 0.07* | 0.71 ± 0.19 | 0.45 ± 0.04* |
| Symmetric dimethylarginine, μmol/L | 0.62 ± 0.05 | 0.48 ± 0.07* | 0.64 ± 0.15 | 0.52 ± 0.07 |
| Creatine, μmol/L | 35.0 ± 12.3 | 45.4 ± 21.5 | 18.0 ± 4.41 | 40.5 ± 21.3* |
| Riboflavin, nmol/L | 22.2 ± 22.2 | 18.3 ± 24.5 | 24.1 ± 25.1 | 17.5 ± 18.2 |
| Ratios | ||||
| Bet:Chol | 4.91 ± 1.86 | 2.77 ± 0.86 | 4.55 ± 0.86 | 2.62 ± 0.65* |
| DMG:Bet | 0.07 ± 0.02 | 0.16 ± 0.05* | 0.06 ± 0.01 | 0.18 ± 0.19 |
| ADMA:Arg | 0.008 ± 0.001 | 0.006 ± 0.001* | 0.008 ± 0.001 | 0.006 ± 0.001 |
Values are means ± SDs. Multivariate ANOVA was performed separately for adequate and low vitamin B-6 status. *Different from nonusers within vitamin B-6 status, adjusted P < 0.05. †Significant difference between groups of low vitamin B-6 status, P < 0.05. Adjustment for multiple testing was based on the Sidak method. ADMA, asymmetric dimethylarginine; Bet, betaine; Chol, choline; DMG, dimethylglycine; OC, oral contraceptive; PLP, pyridoxal 5′-phosphate.
PLP values for nonusers after vitamin B-6 restriction range from 14.8 to 25.3 nmol/L. PLP values for OC users of low vitamin B-6 status range from 14.4 to 29.4 nmol/L.
Student’s t test for cystathionine, a biomarker of marginal vitamin B-6 deficiency, at low vitamin B-6 status.