The antioxidant status and concentrations of coenzyme Q10 and vitamin E in metabolic syndrome.

The purpose of this study was to investigate the levels of coenzyme Q10 and vitamin E and the antioxidant status in subjects with metabolic syndrome (MS). Subjects with MS (n = 72) were included according to the criteria for MS. The non-MS group (n = 105) was comprised of healthy individuals with normal blood biochemical values. The plasma coenzyme Q10, vitamin E concentrations, lipid profiles, and antioxidant enzymes levels (catalase, superoxide dismutase, and glutathione peroxidase) were measured. The subjects with MS had significantly higher concentrations of plasma coenzyme Q10 and vitamin E than those in the non-MS group, but these differences were not significant after being normalized for triglyceride level. The levels of antioxidant enzymes were significantly lower in the MS group than in the non-MS group. The subjects with the higher antioxidant enzymes activities had significant reductions in the risk of MS (P < 0.01) after being adjusted for coenzyme Q10 and vitamin E. In conclusion, the subjects with MS might be under higher oxidative stress resulting in low levels of antioxidant enzyme activities. A higher level of antioxidant enzymes activities was significantly associated with a reduction in the risk of MS independent of the levels of coenzyme Q10 and vitamin E.

A significant correlation between the plasma levels of coenzyme Q10 and vitamin B-6 and a reduced risk of coronary artery disease.

Coronary artery disease (CAD) is the leading cause of death worldwide. The purpose of this study was to investigate the relationship between plasma levels of coenzyme Q10 and vitamin B-6 and the risk of CAD. Patients with at least 50% stenosis of one major coronary artery identified by cardiac catheterization were assigned to the case group (n = 45). The control group (n = 89) comprised healthy individuals with normal blood biochemistry. The plasma concentrations of coenzyme Q10 and vitamin B-6 (pyridoxal 5'-phosphate) and the lipid profiles of the participants were measured. Subjects with CAD had significantly lower plasma levels of coenzyme Q10 and vitamin B-6 compared to the control group. The plasma coenzyme Q10 concentration (ß = 1.06, P = .02) and the ratio of coenzyme Q10 to total cholesterol (ß = .28, P = .01) were positively correlated with vitamin B-6 status. Subjects with higher coenzyme Q10 concentration (≥516.0 nmol/L) had a significantly lower risk of CAD, even after adjusting for the risk factors for CAD. Subjects with higher pyridoxal 5'-phosphate concentration (≥59.7 nmol/L) also had a significantly lower risk of CAD, but the relationship lost its statistical significance after adjusting for the risk factors of CAD. There was a significant correlation between the plasma levels of coenzyme Q10 and vitamin B-6 and a reduced risk of CAD. Further study is needed to examine the benefits of administering coenzyme Q10 in combination with vitamin B-6 to CAD patients, especially those with low coenzyme Q10 level.