Table 1.
Glutathione, Oxidative Stress, and Mitochondrial Function
| Outcome Measure | YAG-0w (N = 11) |
YAG-2w (N = 11) |
OAG-0w YA-0w vs OAG-0w (N = 12) |
OAG-2w (N = 12) |
OAG-16w OAG-0w vs OAG-16w; OAG-16w vs YA-0w (N = 11) |
OAP-0w YA-0w vs OAP-0w; OAP-0w vs OAG-0w (N = 12) |
OAP-2w (N = 12) |
OAP-16w OAP-0w vs OAP-16w (N = 12) |
|---|---|---|---|---|---|---|---|---|
| Glutathione and oxidative stress | ||||||||
| Muscle-glutathione (mmol/kg muscle) | 7.0 ± 1.3 | 7.0 ± 1.3 | 2.4 ± 0.6 p < .001 |
5.3 ± 0.9 p < .001 |
6.3 ± 1.2 p < .001 p = .32 |
2.4 ± 0.8 p < .001 p > .99 |
2.3 ± 0.8 p > .99 |
2.4 ± 0.8 p > .99 |
| RBC-total glutathione (tGSH; mmol/L.RBC) | 1.4 ± 0.2 | 1.5 ± 0.2 | 0.4 ± 0.1 p < .001 |
1.2 ± 0.1 p < .001 |
1.4 ± 0.1 p < .001 p = .84 |
0.5 ± 0.1 p < .001 p = .84 |
0.5 ± 0.1 p = .96 |
0.5 ± 0.1 p = .96 |
| RBC-reduced glutathione (rGSH; mmol/L.RBC) | 1.4 ± 0.2 | 1.4 ± 0.2 | 0.4 ± 0.1 p < .001 |
1.1 ± 0.1 p < .001 |
1.3 ± 0.1 p < .001 p = .86 |
0.4 ± 0.1 p < .001 p = .86 |
0.5 ± 0.1 p = .86 |
0.4 ± 0.1 p = .86 |
| RBC-oxidized glutathione (GSSG; mmol/L.RBC) | 0.1 ± 0.1 | 0.1 ± 0.0 | 0.1 ± 0.0 p > .99 |
0.1 ± 0.0 p = .45 |
0.1 ± 0.1 p > .99 p > .99 |
0.1 ± 0.0 p > .99 p > .99 |
0.1 ± 0.0 p > .99 |
0.1 ± 0.0 p > .99 |
| RBC-GSH/GSSG | 24.6 ± 14.7 | 25.2 ± 16.3 | 7.5 ± 4.8 p = .001 |
14.7 ± 7.6 p = .38 |
27.6 ± 18.2 p < .001 p > .99 |
9.0 ± 6.7 p = .003 p > .99 |
9.6 ± 5.4 p > .99 |
9.5 ± 5.3 p > .99 |
| Plasma TBARS (μM/L) | 4.2 ± 1.0 | 4.1 ± 0.8 | 22.1 ± 3.3 p < .001 |
12.7 ± 3.3 p < .001 |
6.2 ± 1.9 p < .001 p = .28 |
21.9 ± 3.6 p < .001 p = .90 |
21.4 ± 2.3 p = .88 |
22.9 ± 3.5 p = .74 |
| Plasma F2-isoprostane (pg/mL) | 53.9 ± 2.9 | 53.0 ± 2.9 | 216.0 ± 26.9 p < .001 |
119.9 ± 37.6 p < .001 |
59.7 ± 4.0 p < .001 p > .99 |
215.8 ± 19.4 p < .001 p > .99 |
214.2 ± 13.6 p > .99 |
219.8 ± 13.9 p > .99 |
| Mitochondrial function | ||||||||
| Fasting respiratory quotient (RQ) | 0.79 ± 0.01 | 0.78 ± 0.02 | 0.85 ± 0.03 p < .001 |
0.82 ± 0.03 p < .001 |
0.77 ± 0.02 p < .001 p = .27 |
0.84 ± 0.02 p < .001 p = .27 |
0.84 ± 0.03 p > .99 |
0.84 ± 0.03 p > .99 |
| Fasting mitochondrial fatty-acid oxidation (mg/kgLM/min) | 1.2 ± 0.2 | 1.2 ± 0.2 | 0.7 ± 0.3 p < .001 |
0.9 ± 0.3 p < .001 |
1.2 ± 0.2 p < .001 p > .99 |
0.8 ± 0.2 p < .001 p = .47 |
0.8 ± 0.2 p > .99 |
0.8 ± 0.2 p > .99 |
| Fasting mitochondrial glucose oxidation (mg/kgLM/min) | 0.9 ± 0.6 | 0.9 ± 0.4 | 2.2 ± 0.7 p < .001 |
1.5 ± 0.6 p < .001 |
0.8 ± 0.3 p < .001 p > .99 |
2.0 ± 0.5 p = .001 p > .99 |
2.1 ± 0.6 p > .99 |
2.1 ± 0.8 p > .99 |
| Rate of palmitate oxidation (μmol/kgLM/min) | 146.8 ± 25.5 | 151.6 ± 19.2 | 119.0 ± 11.9 p = .003 |
139.7 ± 24.3 p = .007 |
157.1 ± 31.7 p < .001 p = .65 |
122.9 ± 10.6 p = .010 p > .99 |
125.0 ± 12.5 p > .99 |
121.8 ± 9.9 p > .99 |
| Rate of acetate oxidation (μmol/kgLM/min) | 227.4 ± 42.8 | 228.4 ± 40.6 | 258.4 ± 40.3 p > .99 |
254.8 ± 52.8 p > .99 |
249.9 ± 44.5 p > .99 p > .99 |
259.2 ± 72.4 p > .99 p > .99 |
258.3 ± 43.5 p > .99 |
259.4 ± 51.7 p > .99 |
| Energy expenditure (kcal/d) | 1 348 ± 246 | 1 363 ± 269 | 1 516 ± 223 p = .75 |
1 420 ± 191 p = .28 |
1 438 ± 214 p > .99 p > .99 |
1 384 ± 258 p > .99 p > .99 |
1 434 ± 233 p > .99 |
1 365 ± 279 p > .99 p > .99 |
Notes: Data are summarized by means with standard deviations. Baseline comparisons are shown between YA-0w vs OAG-0w, YA-0w vs OAP-0w, and OAG-0w vs OAP-0w. Postsupplement comparisons are shown as OAG-0w vs OAG-16w, OAP-0w vs OAP-16w. p Values are significant at values < .05. GlyNAC = combination of glycine and N-acetylcysteine; YAG = young adults supplemented with GlyNAC; YA = young adults; OAG = older adults receiving GlyNAC; OAP = older adults receiving placebo; RBC = red blood cell; TBARS = Thiobarbituric acid reducing substances.