Typescript (photocopy). / Digitized by Kansas Correctional Industries

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

The vitamin B-6 status of seemingly healthy adolescent girls was determined using several accepted and proposed parameters in an effort to establish guidelines for status evaluation. HPLC-derived plasma B-6 vitamer [pyridoxal phosphate (PLP), pyridoxine phosphate (PNP), pyridoxamine phosphate (PMP), pyridoxal (PL), pyridoxine (PN), and pyridoxamine (PM)] and 4-pyridoxic acid (4-PA) concentrations and urinary 4-PA levels of 28 white adolescent females, 12-15 years, having radiomonitored plasma PLP concentrations and coenzyme stimulation of erythrocyte alanine aminotransferase activities indicative of adequate status were determined. Mean daily vitamin B-6 and protein intakes of the subjects were 1.48 mg and 78.3 g, respectively. The ranges for plasma B-6 vitamer and 4-PA concentrations for these subjects which had seemingly adequate vitamin B-6 status were as follows: (nmol/L) PLP, 40.9-122.2; PNP, 0-16.1; PMP, 0-8.1; PL, 0- 15.0; PN, 0-21.9; PM, 0-17.8; and 4-PA, 0-55.7. PLP was the predominant plasma B-6 vitamer as well as being the only vitamer found in plasma of all subjects. Urinary 4-PA concentrations of the girls ranged from 0.11-2.50 pmol/mmol creatinine. The B-6 vitamer values of these white adolescent girls should be of use in the establishment of normal ranges for vitamin B-6 status parameters. HPLC methodologies seem to be advantageous for the rapid and accurate assessment of vitamin B-6 status. / Ph. D.

Submitted in fulfillment of the requirements of the degree of Doctor of Technology: Health Sciences, Durban University of Technology, Durban, South Africa, 2015. / Background: In a vulnerable low-income group with a confirmed high risk of cardiovascular disease, like the elderly in the Sharpeville care centre, an acute intervention is needed in order to improve their health profile. Previous studies suggested homocysteine lowering by vitamin B12, B6 and folate supplementation. The effect of vitamin B12, B6 and folate supplementation on the inflammatory response, thrombotic risk, lipid profile, hypertension, risk of metabolic syndrome and homocysteine metabolism in an elderly, black South African population has never been reported. Objectives: The main aim of this interventional study was to assess the effect of vitamins B12, B6 and folate supplementation at 200% RDA for six months on cardiovascular risk markers of an elderly semi-urbanised black South African community. Design: This study was an experimental intervention non-equivalent control group study design in 104 purposively selected samples of all the elderly attending the day-care centre. Setting and participants: A homogeneous group of respondents was included in the study. All subjects were equivalent in age (>60 years), race (black), unemployed/pensioners (socio-demographic) and 60 years and older attending a day care centre in Sharpeville, situated in the Vaal region, Gauteng, SA. Measurements: The distinctiveness of this study lies in the broad panel of parameters evaluating the CVR in correlation with the increased nutritional intake of vitamin B6, B12 and folate. These included: weight, height, waist, serum cholesterol, high density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides, blood pressure, fibrinogen, high-sensitivity C-reactive protein (HS–CRP), homocysteine, vitamin B12, folate, glucose, insulin, adiponectin and fibronectin. Results: A very high incidence (66.36%) of hyperhomocysteinaemia is present in the sample. The mean serum homocysteine level in hyperhomocysteinaemic individuals decreased statistically significantly from 25.00±8.00 umol/l to 18.80±12.00 umol/l after the intervention. The number of respondents with an increased homocysteine level decreased from 100% (baseline) to 67% (follow-up). The supplementation was beneficial (statistically significant changes) to the glucose levels, fibrinolytic status, vitamin B6 serum levels, fibronectin levels and haemopoeiesis (decreased macrocytosis) of all the individuals (regardless of their homocysteine status). Conclusion: It is concluded that supplementation of vitamins B6, B12 and folate at 200% RDA for six months is an effective homocysteine-lowering approach as a strategy to reduce hyperhomocysteinaemia in an elderly population and thereby reduce cardiovascular risk (CVR). The supplementation intervention mentioned is not an effective multifactorial strategy to decrease CVR although beneficial effects were found with other CVR markers independent of homocysteine status.

The aim of this study was to investigate the vitamin B-6 status of Saudi adult males and compare the status between rural and urban subjects. Fifty-one adult male subjects were recruited from urban (n=31) and rural (n=20) populations of Riyadh. These subjects were reclassified to cigarette smokers (n=19), water pipe smokers (n=5) and non-smokers (n=27). The study also investigated the intake of macronutrients and selected micronutrients. In addition, the study investigated other health indicators including Body Mass Index (BMI), hematocrit, hemoglobin, plasma alkaline phosphatase activity and albumin concentration, urinary creatinine and urea nitrogen excretion. The mean of vitamin B-6 intake, B-6 to protein ratio, plasma pyridoxal phosphate (PLP) concentration and urinary 4-PA excretion in urban group were 2.18 ± 0.62 mg/day, 0.022 ± 0.008 mg/g, 39.3 ± 18.0 nmol/L and 4.6 ± 2.3 μmol/day, respectively. In rural group, these measures were 2.15 ± 0.65 mg/day, 0.021 ± 0.004 mg/g, 40.5 ± 14.6 nmol/L and 4.4 ± 2.3 (μmol/day, respectively. These measures indicated adequate status with no significant difference between the two groups. The mean intake of calcium, folate, vitamin D, zinc and dietary fiber was lower than recommendation of the Dietary Reference Intakes (DRI) in both groups. Health indicators were within normal range except for BMI, which indicated a prevalence of overweight and obesity in both urban (27.1 ± 5.5 Kg/m²) and rural (28.2 ± 6.0 Kg/m²) subjects. Comparison of the three smoking groups showed that the water pipe smokers compared to cigarette smokers and non-smokers groups had significantly higher mean intake of vitamin B-6 (2.51 ± 0.73 mg/day), which resulted in higher concentrations of plasma PLP, pyridoxal (PL), red blood cells PLP and urinary 4-PA (54.9 ± 23.1 nmol/L, 21.5 ± 10.0 nmol/L, 33.7 ± 8.5 nmol/L and 6.9 ± 4.7 μmol/day, respectively). Cigarette smokers had significantly lower concentration of plasma PLP (30.9 ± 12.5 nmol/L) compared to non-smokers (40.0 ± 12.9 nmol/L) without a significant difference in vitamin B-6 intake. Hematocrit and hemoglobin were significantly higher in smokers (50 ± 3% and 167 ± 11 g/L, respectively) compared to non-smokers (48 ± 3% and 160 ± 9 g/L, respectively). The results of this study suggest that vitamin B-6 status of adult males in Riyadh is adequate with no urban vs. rural variation. / Graduation date: 2004