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.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Over 60% of the population in K'asho Got'ine, NWT, obtained less than 2/3 of the Recommended Nutrient Intakes (RNI) for vitamin A and calcium, as reported in a previous nutritional assessment. Focus group discussions and a food preference assessment were conducted with adults in order to identify the cultural, ecological, and socioeconomic factors (food attributes) as well as the individual preferences which influence the consumption of vitamin A and calcium-rich traditional and market foods in K'asho Got'ine. The major attributes limiting intakes of traditional food rich in vitamin A and calcium included: lack of equipment for hunting/fishing; seasonality; distance traveled to obtain certain foods; occasional unhealthy appearance of food; no hunter/fisher in the household. The major food attributes reported as barriers to greater intakes of selected market foods were: cost, freshness, intolerance to certain items, availability and unfamiliarity. Foods that received the highest preference scores were rabbit liver, loche liver, and Canada goose meat (smoked/dried) for vitamin A-rich foods and connie eggs, rabbit flesh, woodland and barrenland caribou head for calcium-rich foods. Criteria for selection of traditional and market foods to promote in the community included: (1) convenience of the food; (2) difficulty to overcome barriers to increasing food consumption; (3) concentration level of contaminants in certain traditional food; and (4) food preference score. This study identified available and underutilized traditional and market foods rich in vitamin A and calcium which are most acceptable to the community, and may be promoted in future nutrition intervention programs.

We investigated the effect of pyridoxine supplementation on the utilization of protein in a low-protein, plant-based diet in four subjects (2 men and 2 women), aged 21 to 38 years. Following two days of a negligible protein diet, this 34 day study was divided into three dietary periods: the subjects received a low-protein, plant-based diet during period I for 10 days (no pyridoxine supplement), the same diet but with the addition of 50 mg pyridoxine HCl during period II for 7 days, and their self-chosen diets during period III for 15 days (no pyridoxine supplement). Data for period III will be reported elsewhere. The greatest portion of protein in the experimental diet was furnished by pinto beans (1.02 g nitrogen) and peanut butter (0.86 g nitrogen); nitrogen intake was kept constant at 4.56 g/d for the men and 4.15 g/d for the women during periods I and II. These diets administered during periods I and II provided 0.907 mg of vitamin B-6 for the men and 0.758 mg of vitamin B-6 for the women and was adequate in other nutrients except for protein. Overall, the effect of 50 mg pyridoxine HC1 supplementation on the utilization of protein in a low-protein plant-based diet was not statistically significant (p > 0.05) on the basis of a paired t-test for the parameters measured: nitrogen balance, apparent protein digestibility, as well as plasma and urinary urea nitrogen. Furthermore, we obtained conflicting results, when the subjects received pyridoxine, their plasma urea nitrogen increased slightly (suggesting increased protein degradation), while the percent of total urinary nitrogen excretion as urea nitrogen decreased (suggesting decreased protein degradation). These changes were not statistically significant, but limitations in the nitrogen balance technique and the analytical procedures we used may have contributed to these conflicting results. We suggest that a longer study with more subjects may show a greater improvement of plant protein utilization than we had observed. / Graduation date: 1990

Thesis (M.S.)--Oregon State University, 2003. / Includes bibliographical references (leaves 53-56). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.S.)--Oregon State University, 2003. / Includes bibliographical references (leaves 53-56).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed July 10, 2007). PDF text: vii, 130 p. : ill., map. UMI publication number: AAT 3254332. Includes bibliographical references. Also available in microfilm and microfiche formats.