Previous studies suggest that vitamin B-6 supplementation can alter fuel metabolism during
exercise and plasma amino acid levels at rest. To examine the effect of vitamin B-6
supplementation on plasma fuel substrates and amino acid levels during exercise, five trained
males (age: 29±7; V0₂ max: 54.7±6.2 ml/kg/min) performed two separate submaximal,
endurance, exercise tests on a cycle ergometer. Subjects were exercised to exhaustion at
74.5±7.8% V0₂ max in a fasted condition on the seventh morning of two separate nine day
controlled diet periods. The first exercise test (T1) occurred following a control or non-supplemented
(NS) diet (i.e. 1.9 mg B-6/day), and the second exercise test (T2) occurred
following a vitamin B-6 supplemented (S) diet (i.e. 1.9 mg B-6/day + 20 mg PN/day). Blood
was drawn pre, during (i.e. 60 minutes into exercise), post, and post-60 minutes of exercise,
and plasma was analyzed for glucose, lactic acid, glycerol, free fatty acids (FFA), and amino
acids. Expired air was collected for three minutes at 10 minute intervals during both tests.
Although not statistically different, there were observed trends for higher mean lactate levels
and lower mean glycerol and FFA levels in T2 (S) compared to T1 (NS). Mean lactate, glycerol,
and FFA concentrations all changed statistically significantly over time in both exercise tests.
Mean plasma tyrosine levels were significantly lower (p = 0.007) at post-60 minutes of exercise
and mean plasma methionine levels were significantly lower (p = 0.03) at post-exercise in T2
relative to T1. Of the 13 amino acids quantitated, only alanine and histidine concentrations changed significantly over time. Although not statistically significant, mean respiratory
exchange (R) values tended to be higher in T2 compared to T1. Mean oxygen consumption
values were significantly higher (p = 0.02) during the first 10 minutes of exercise and at
multiple later time points showed a trend for being higher in T2 compared to T1. No
statistically significant differences were observed in subjects' performance times to exhaustion
between T1 (1:35:49; hr:min:sec) and T2 (1:31:56). These results indicate that vitamin B-6
supplementation can potentially alter fuel metabolism and plasma amino acid levels during
exhaustive endurance exercise; however, not to such a degree that one's endurance capacity
is affected. / Graduation date: 1995
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27134 |
| Date | 16 August 1994 |
| Creators | Virk, Ricky S. |
| Contributors | Leklem, James E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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