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The plasma concentrations and the dietary intakes of vitamin E were determined in 20 elderly and ten young subjects. Five subjects in the older group were known to take supplements of vitamin E. The mean concentration of tocopherols (determined chemically) in the plasma of all unsupplemented subjects was 1.12 ± 0.33 mg/100 ml. No significant difference in plasma tocopherols due to age or sex was found. However, the mean concentration in the plasma of the supplemented subjects (1.39 ± 0.26 mg/100 ml) was significantly higher than that of the unsupplemented subjects. The mean alphatocopherol activity in the diets (estimated from a three-day diet study) of all subjects was 8.51 ± 3.74 mg. The young group had a significantly greater intake than the elderly group. No significant difference between the sexes was observed. The mean ratio of alpha-tocopherol activity to polyunsaturated fatty acids (E:PUFA) in the diets of all subjects was 1.47 ± 1.17 mg/gm. The significant difference between the age groups or sexes was observed. A significant linear relationship between plasma tocopherols and dietary alpha-tocopherol activity or the E:PUFA ratio was not found. Neither age, sex nor dietary intake was related to a significant change in plasma tocopherols. However, subjects using supplements of vitamin E had a significantly higher mean plasma concentration of tocopherols. / Graduation date: 1975

This investigation was designed to add to present understanding of vitamin B-6 (B6) metabolism during exercise. Ten women, 5 aerobically trained and 5 untrained, were fed 4 controlled diets: a moderate carbohydrate (49%) (MCHO) for 2 weeks, a high carbohydrate (63%) (HCHO) for one week, MCH0+B6 for 2 weeks, and HCH0+B6 for 1 week. A one week MCHO diet separated the non-supplemented (2.3 mg B6) and supplemented (10.3 mg B6) diets. The V02 max of each subject was determined prior to the study. An exercise test was completed on day 5 or 6 of weeks 2, 3, 6, and 7. The test consisted of 20 minutes of cycle ergometer exercise at 80% V02 max, preceded by 10 minutes of warm-up and followed by a 5-10 minute active recovery. Blood samples were collected pre exercise (pre), 2-3 minutes post (post), 30 minutes post (p30), and 60 minutes post (p60) exercise. Samples were analyzed for plasma vitamin B-6 (PB6), hematocrit, and hemoglobin. Urine was collected daily in 24-hr aliquots and samples were analyzed for 4-pyridoxic acid (4PA) and creatinine. For all diets, exercise resulted in a significant increase in PB6 from pre to post and a significant decrease from post to p60, the magnitude of the change being greater with supplementation. PB6 fell below pre levels by p60 for all exercise sessions. 4PA increased significantly from the day before exercise to the day of exercise on all diets. There was no significant effect of dietary carbohydrate on levels of PB6 or excretion of 4PA. ANOVA showed no difference between the groups for PB6 or 4PA, though the trained group had lower PBS and greater 4PA excretion throughout the study despite the controlled intake. Tissue redistribution of B6 seems to occur with exercise. The increased magnitude of change in PB6 with exercise after supplementation suggests an increased storage of the vitamin, most likely associated with glycogen phosphorylase in the muscle. Trained women may have lower levels of PB6 and greater 4PA excretion as the result of a regular exercise program. However, supplementation with B6 cannot be recommended since the status of all subjects was adequate with the diet fed. / Graduation date: 1985

The bioavailability of vitamin B-6 from four selected foods was investigated in five men, aged 22 to 25 years, who were receiving a pyridoxine supplement. The subjects received a constant diet containing 1.34 mg of vitamin B-6 throughout this five-week study, except on Saturdays and Sundays when they ate their self-chosen diets. Starting on day 6 of week 1, following a five-day adjustment period, the subjects received orally 5-mg crystalline pyridoxine supplement daily, except on Tuesday and Thursday of each week. On these two days, the subjects were given orally 0 mg or 2 mg of crystalline pyridoxine, or test doses of bananas, filberts, soybeans and beef which contained around 2 mg of vitamin B-6. Vitamin B-6 was determined by microbiological assay with Saccharomyces uvarum. Vitamin B-6 bioavailability in the test food was determined by comparing 24-hour urinary total vitamin B-6 in response to the test food doses to that excreted following a 2-mg crystalline pyridoxine dose in each subject. Compared to the 100 percent bioavailability of the 2-mg crystalline PN dose, the average vitamin B-6 bioavailability in bananas was 115 + 32% and that in filberts, soybeans and beef was 93 + 8%, 73 + 20% and 87 + 7%, respectively. The metabolism of vitamin B-6 in pyridoxine-supplemented subjects was also investigated by measuring changes in plasma total vitamin B-6 which increased and was stablized after three weeks of pyridoxine supplementation. It was concluded that urinary total vitamin B-6 in pyridoxine-supplemented subjects can be used as a measure of vitamin B-6 bioavailability from test food doses. / Graduation date: 1983

Thesis (Ph. D.)--University of Queensland,2001. / Includes bibliographical references.

Thesis--PlanA (M.S.)--University of Wisconsin--Stout, 2003. / Includes bibliographical references.