Comparison of plasma and intake levels of antioxidant nutrients in patients with chronic obstructive pulmonary disease and healthy people in Taiwan: a case-control study.

The imbalance of oxidant/antioxidant plays an important role in the development of chronic obstructive pulmonary disease (COPD). There is increasing evidence that individuals with high antioxidative nutrient levels in the diet or in blood tend to maintain better lung function. This study was conducted to determine whether COPD patients in Taiwan have lower plasma concentrations of antioxidative nutrients than do healthy people, and whether the dietary habits of COPD patients in Taiwan affect their intake of vitamin C and carotenoids. Thirty-four COPD patients and 43 healthy persons (with normal lung function) aged 50 years or older were recruited. Fasting venous blood was collected to measure concentrations of vitamins A, C, and E and carotenoids. Endogenous and H2O2-induced additional DNA damage (markers of oxidative stress) in white blood cells were assayed. Dietary intakes of vitamin C and carotenoids were assessed by a food-frequency questionnaire. Compare to the healthy controls, COPD patients had significantly lower plasma concentrations of vitamins A, C, and E; α- and β-carotene; and total carotenoids but significantly higher endogenous and H2O2-induced white blood cell DNA damage. Intakes of vitamin C and several carotenoids were lower in the COPD group, and COPD patients consumed significantly fewer vegetables and fruits than did the healthy controls. In conclusion, COPD patients in Taiwan have lower levels of antioxidative nutrients in their plasma and diet than do healthy people. Intakes of vitamin C and carotenoids are correlated with dietary habits.