The purpose of this study was to examine the effect of extreme exercise on vitamin B-6 metabolism and urea nitrogen. Nine men and five women completed two 5-day trials; Trial 1 (T1) included a 50-km ultramarathon on day 4 and during Trial 2 (T2) subjects were "inactive" on day 4. During both trials, subjects consumed a diet providing men 2.0 and women 1.5 mg of vitamin B-6. With the exception of the ultramarathon, T1 activity was replicated during T2. Twenty four-hour urine collections were completed and blood was drawn pre-race (pre), mid-race (mid), post-race (post) and 60 minutes post race (P-60). On the inactive, day blood was drawn at the same intervals. Plasma was analyzed for pyridoxal 5'-phosphate (PLP), pyridoxal, 4-pyridoxic acid (4-PA), urea nitrogen (PUN), creatinine, albumin, glucose, and lactate concentration and alkaline phosphatase activity. Urine was analyzed for 4PA, creatinine, and total urinary nitrogen (TUN). During T1, compared to pre, plasma PLP concentration increased 17% at mid, decreased 5% by post, and 19% by P-60. During T2, plasma PLP concentration decreased 13% pre to P-60. During T1, plasma 4-PA concentration increased 135% and the percent dietary vitamin B-6 that was excreted as urinary 4-PA the day of the ultramarathon was higher than that excreted the day before and the day after. During T1, from pre to post mean PUN concentration increased 36.9%, and the average rate ofincrease from pre to mid, mid to post, and post to P60 was 0.5, 1.75, and 2 mg/dL/hour, respectively. During T1 on days 3, 4, and 5,88%, 100%, and 95% of nitrogen intake was excreted in the urine compared to 86%, 83%, and 84% for the same days during T2. The day of the ultramarathon, 24-hour TUN excretion was 2 g higher than the previous day. Extreme exercise of greater than six hours initially increases the plasma concentration of PLP but ultimately results in a significant decrease in plasma PLP, an increase in plasma 4-PA, and an increase in percent of dietary vitamin B-6 (as 4-PA) excreted in the urine. Additionally, the rate of change in PUN inoeases as duration increases. / Graduation date: 2001

This investigation was conducted to determine the effect of estrogen replacement therapy (ERT) on vitamin B-6 status of postmenopausal women. Nineteen postmenopausal women served as subjects. Nine (54.7 + 4.7 years) were taking ERT (experimental group); ten (56.8 + 2.3 years) were not (control group). For three consecutive days, subjects recorded their dietary intake and collected their 24-hour urine specimens. On the fourth day, a fasting blood sample was drawn from the subjects. The dietary intake of vitamin B-6, as well as the concentration of total vitamin B-6 in plasma (PB6; and urine (UB6) were measured. PB6 and UB6 were determined by a microbiological method with Saccharomyces uvarum as the assay organism. The mean age, height, hematocrit and hemoglobin values were similar for the two groups. The experimental group was significantly heavier than the control group (p<0.05). The experimental group had a lower mean PB6 than the control group: 47.7 ± 19.7 nmol/L vs. 56.2 + 20.6 nmol/L. These means were not significantly different (p=0.05). PB6 was positively correlated with dietary vitamin B-6 intake (p=0.0001) and vitamin B-6 to protein ratio (p=0.0021). When the means were adjusted for dietary vitamin B-6 and the vitamin B-6 to protein ratio, the mean PB6 of the experimental group (42.7 nmol/L) was significantly lower than that of the control group (60.6 nmol/L) (p<0.05). PB6 was not positively correlated with either age (r=0.20) or the vitamin B-6 dietary history score (r=0.15). UB6 was similar for the two groups. UB6 correlated positively with daily dietary intake of vitamin B-6 (r=0.51, p<0.05) and the ratio of vitamin B-6 to protein (r=0.47, p<0.05), UB6 was not significantly correlated to urine volume (r=0.05). The mean daily intakes of vitamin B-6 and protein were similar for the two groups. One of the 19 subjects had a vitamin B-6 intake that was less than 67 percent of the RDA. Most subjects' (89%) intake of vitamin B-6 was adequate when the ratio of 0.016 mg of vitamin B-6 per g of protein was used as the standard. / Graduation date: 1990

Graduation date: 1992

Vitamin B-6 is a vitamin often promoted by the popular press as a cure all. It's role is also being studied in regard to pre-menstrual syndrome, myocardial infarction and alterations in lipid and fatty acid metabolism. This study was designed to investigate whether there was a difference between vitamin B-6 blood levels, during a baseline study, a period of vitamin B-6 depletion and vitamin B-6 supplemention in ten men ages 21-37. The effect of each diet on total cholesterol was also investigated.The experimentally accessible population for this study Laboratory as part of a larger study conducted by Dr. Stephen Coburn of the Fort Wayne State Developmental Center.Analysis of the data indicated:1) A significant difference between red blood cell pyridoxal phosphate and blood plasma levels of vitamin B-6 during the baseline, depletion and supplementation phases in ten men 21-37.2) Total serum cholesterol levels fell significantly through all phases of the study. High density lipoproteins fell significantly during the depletion phase but did not rise significantly during the supplementation phase. Low density lipoproteins showed no significant difference during the three phases of the study. When dietary records were evaluated mean dietary intake during the baseline and supplementation phases of the diet met the Recommended Dietary Allowance (RDA) for vitamin B-6. Mean protein intake also met the RDA with 102.1 grams during the baseline phase and 106.1 grams during the supplementation phase. These intakes are consistent with those found in previous studies conducted by the USDA. Mean intake of fat was lower than the 30 percent of calories recommended by the American Heart Association but wide variation existed among subjects.No physical symptoms of vitamin B-6 deficiency manifested themselves during the study. Subjects reported no other problems associated with low vitamin B-6 intakes.The data indicated that vitamin B-6 intake effects the amount of red blood cell plasma pyridoxal phosphate and plasma vitamin B-6. No clear effect can be found between vitamin B-6 intake and serum cholesterol levels. "Normal" diets also appeared to provide adequate vitamin B-6 to meet both RDA's and somatic needs. Wide variation seems to exist, however, among individuals. / Department of Home Economics

The vitamin B-6 status of 11 white adolescent females living in the Blacksburg/Roanoke, Virginia area was evaluated by dietary intakes, coenzyme stimulation of erythrocyte alanine aminotransferase (F-ALAT) activities, and plasma total vitamin B-6 measured microbiologically. Heights and weights of the group were generally within ranges. The vitamin B-6 intakes of the adolescents were 1.47 ± 0.49 mg/day (mean ± SD). Three subjects, or 27.3%, the same subjects classified as inadequate in status by coenzyme stimulation of E-ALAT, were classified as marginal or inadequate in status using ≤ 25 ng/ml total plasma vitamin B-6 levels as the criterion. The plasma pyridoxal, pyridoxine, pyridoxamine and total B-6 vitamer concentrations of subjects having inadequate E-ALAT values were lower, generally significantly, than those of girls with adequate levels. In the subjects with adequate status, the vitamer found in the largest plasma concentration was pyridoxine. A significant correlation (r = 0.82, p < 0.01) was observed between total plasma vitamin B-6 levels determined microbiologically and coenzyme stimulation values. / Master of Science

The influence of vitamin B-6 intake on vitamin B-6 status and the concentration of B-6 vitamers in milk of 21 white lactating women (21 to 35 years) was examined at 3 to 7 months postpartum. None of the women met the RDA for lactating women of 2.5 mg/day when considering vitamin B-6 intakes from food sources alone. All subjects taking vitamin B-6 supplements had adequate vitamin B-6 status as determined by coenzyme stimulation of erythrocyte alanine aminotransferase activity; all subjects not taking vitamin B-6 supplements had inadequate vitamin B-6 status. Plasma pyridoxal 5-phosphate values were significantly higher for subjects in the supplemented than in the nonsupplemented group. Pyridoxal, pyridoxamine, pyridoxine, and total vitamin B-6 concentrations in milk were higher, sometimes significantly, in the supplemented than in the unsupplemented group as determined by microbiological assay and HPLC. There were significant correlations between data obtained by the microbiological and HPLC analyses for pyridoxal and total vitamin B-6 concentrations. Pyridoxal was the predominant B-6 vitamer found in human milk. Distribution of the B-6 vitamers appeared to stay relatively constant despite vitamin B-6 status. / Master of Science

Two studies were conducted to determine the effect of varying vitamin B-6 (B- 6) status on lymphocyte mitogenic response and pyridoxal 5'-phosphate (PLP) concentration in peripheral blood mononuclear cells (PBMC) in young women. In the first study, women were fed 1 mg/d for the first week and 1.5, 2.1 and 2.7 mg/d during 2 weeks of each of the subsequent 3 experimental periods. Plasma PLP and urinary 4: pyridoxic acid (4-PA) were increased with increasing B-6 intake. B-6 intake > 2.1 mg significantly enhanced lymphocyte proliferation, and non-significantly increased plasma interleukin-2 concentration. Lymphocyte proliferation was significantly correlated with B-6 intake, erythrocyte aminotransferase activity coefficients and plasma PLP. PBMC PLP tended to increase after 2 weeks of 2.7 mg B-6 intake, and was significantly correlated with plasma PLP. In the second study, women consumed their normal diets whose estimated mean dietary B-6 intake was 0.9 mg for 27 d. For the last 20 d, all subjects were given a multivitamin supplement containing 1.8 mg B- 6, and half of the subjects were given an additional 50 mg of B-6 supplement. Plasma PLP and urinary 4-PA were significantly higher in the group with 50 mg B-6, but lymphocyte proliferation did not significantly differ between the groups. After 10 d of supplementation, lymphocyte proliferation was significantly higher than the other time points. A significant increase in PBMC PLP was observed after 3 days and 20 days following 50 mg and multivitamin supplementation only, respectively. After 20 days of supplementation, there was no significant difference of mean PBMC PLP between the groups. PBMC PLP was significantly correlated with plasma PLP, PL and 4-PA. In both studies, no strong relationship was found between PBMC PLP and lymphocyte proliferation. The findings from these studies demonstrate no further benefit of a higher B-6 intake than 2.1 mg on lymphocyte mitogenic response, once the response was significantly enhanced with B-6 intake 0.8 mg higher than the current recommendation. Finally, results from two studies suggest that the current recommendation of vitamin B-6 for young women may not be adequate to maximize lymphocyte mitogenic response and PLP concentration in PBMC. / Graduation date: 2002

This study examined the effect of vitamin B-6 supplementation and exhaustive submaximal exercise on plasma catecholamine concentrations, and the relationship between plasma catecholamines and fuel use, heart rate and oxygen consumption. Five trained men (age= 18-35 years; V0₂max=53 ml 0₂/kg/min.) participated in two controlled dietary periods that were identical except for the addition of 20 mg/d pyridoxine (PN) supplementation during the second period. On the seventh morning of each period, fasted subjects exercised to exhaustion on a cycle ergometer at 74.5% ± 7.8 V0₂max. Blood was drawn pre-exercise (twice), 60 minutes into exercise, immediately post-exercise and 60 minutes post-exercise. Plasma was analyzed for norepinephrine, epinephrine, glucose, pyridoxal 5'-phosphate (PLP), lactic acid, glycerol and free fatty acids (FFA). Heart rate and oxygen consumption were measured pre-exercise and at 10-minute intervals during exercise. Mean plasma PLP concentration was significantly higher during the supplemented versus the nonsupplemented trial at all time points. There were no statistically significant differences in mean plasma catecholamine concentrations or mean plasma fuel concentrations between the nonsupplemented and supplemented trials at any of the time points examined. There were significant changes in the mean plasma concentrations of norepinephrine, lactic acid, glycerol and FFA over time in both trials. Respiratory exchange ratios (R) were higher during the supplemented trial compared to the nonsupplemented trial, but the differences did not attain statistical significance. There were no significant differences in mean exercise times to exhaustion or mean heart rates between the trials. The overall mean oxygen consumption during exercise was consistently higher during the supplemented versus the nonsupplemented trial and the difference attained significance (p=0.016) at one time point (10 min.). The mean oxygen consumption during rest was lower during supplementation versus nonsupplementation, but the difference was not statistically significant. The percent plasma volume change (PVC) was significantly greater at post-exercise, relative to pre-exercise, during the supplemented versus the nonsupplemented trial. The percent PVC also increased significantly over time during the supplemented but not the nonsupplemented trial. These results suggest that 20 mg/d of vitamin B-6 supplementation does not effect plasma catecholamine concentrations, fuel utilization or heart rate at rest or during submaximal exercise to exhaustion. The results may suggest a higher oxygen consumption during exhaustive exercise after PN supplementation. / Graduation date: 1996

Trained male cyclists (6 in study 1, 5 in study 2) cycled to exhaustion (EXH) at 75% of VO₂ max twice; once in the non-supplemented (NS) state and once in the vitamin B-6 (B-6)(20 mg PN) supplemented (S) state. The diet contained 2.3 mg B-6 in study 1 and 1.9 mg B-6 in study 2. Urine was collected during each dietary period. During each exercise (EX) test, blood was drawn prior to (PRE), one hour during (DX), immediately after (POST) and one hour after (POST 60) EX and sweat was collected. Compared to baseline (PRE) levels, plasma pyridoxal 5'-phosphate (PLP) and vitamin B-6 (PB-6) concentrations increased at DX, decreased at POST, and decreased below PRE at POST 60 in the NS and S states. EX to EXH in the S state resulted in a greater increase in PLP DX in study 1 (31% increase vs. 16%) and PB-6 in study 2 (25% increase vs. 11%) as compared to the NS state. Red blood cell (RBC) PLP significantly increased from POST to POST 60 in the S state in study 2. The excretion of urinary 4-pyridoxic acid (4-PA) and urinary B-6 (UB-6) was not significantly altered by EX to EXH. The mean excretion of 4-PA was significantly greater in the NS state in study 2 (7.98 ±1.83 mmol/d) as compared to the excretion in study 1 (6.20 ±0.93 mmol/d), whereas the excretion was significantly greater in the S state in study 1 (92.2 ±8.69 mmol/d) compared to the excretion in study 2 (82.7 ±6.16 mmol/d). The percent of B-6 intake excreted as UB-6 (6% in study 1 and 10% in study 2) was significantly different between the studies in the NS state. Vitamin B-6 supplementation did not significantly alter the rise in growth hormone (hGH) concentration seen with EX to EXH. The loss of B-6 in sweat with EX to EXH was not altered by B-6 supplementation. The loss of B-6 in sweat ranged from 0.0011 mmol to 0.0039 mmol. Therefore, EX to EXH in the B-6 S state resulted in a greater increase in plasma PLP and PB-6 DX as compared to the NS state. The decrease in PB-6 and PLP at POST 60 in the S state coincided with a significant increase in RBC PLP, suggesting the movement of B-6 from the plasma into the RBC at POST 60. EX to EXH and B-6 supplementation did not alter the excretion of 4-PA or UB-6 suggesting that B-6 metabolism was unchanged. The loss of B-6 in sweat was comparable to previously reported values and was not altered by B-6 supplementation. B-6 supplementation did not alter the changes in hGH resulting from EX to EXH alone. / Graduation date: 1995

Vitamin B-6 status was examined in a group of 46 elderly subjects who were selected from nursing home residents, hospital patients, and free living individuals in Denton County. Subjects were limited to men and women over 60 years of age. Erythrocyte aspartate aminotransferase stimulation with pyridoxal phosphate (in-vitro) was studied as the biochemical criterion of vitamin B-6 status. The pyridoxine status of these 46 subjects (the reference group) was measured in order to be able to identify people with a relatively poor B-6 status. A sub-group of the reference group was composed of 4 subjects who took B-6 supplements (supplemented group). There was no significant difference (0.05 level) in the basal activity, stimulated activity, percentage stimulation, or body weight, after treatment with 10 mg pyridoxine hydrochloride for 4 weeks, even though all 4 subjects had an improved B-6 status (based on percentage stimulation) after taking the supplement. The data indicated that of the 4 subjects tested, 2 showed a large change in the basal activity, stimulated activity, and percentage stimulation. The lack of significant difference (0.05 level) was probably due to a small sample size. One subject reported an increased appetite and body weight after treatment with pyridoxine.