Vitamin D3 supplementation on plasma antioxidant enzymes in D3 deficient patients with COPD - a randomized controlled trial

Background: Free radical is a crucial factor for progression of COPD. Antioxidant enzymes, including superoxide dismutase (SOD) and catalase (CAT) have been well known to reduce morbidity of chronic disease. Vitamin D3 has antioxidant effect in human body. Objectives: To assess the effects of D3 supplementation on plasma SOD and CAT levels in D3 deficient COPD patients. Method: A double blinded placebo controlled randomized clinical trial was carried out on 30 vitamin D3 deficient male, smoker and stable COPD patients of age >40 years. All the patients were randomly allocated to ‘Study' (n=15) or ‘Control' (n=15) and their baseline plasma SOD and CAT were measured. Study patients received 80,000 IU (2 oral capsules) of D3 per week for first 13 weeks. Subsequently, after checking their serum 25(OH)D or Ca2+, they received 40,000 IU (1 oral capsule) of D3 either per 1 week or per 2 weeks or per 6 weeks or no further supplementation for next 13 weeks. All the ‘Control' patients received two oral capsules of placebo weekly for consecutive 26 weeks. Additionally, all patients of both groups were also advised to have sunlight exposure (within 11 to 14 hrs) at least for 5 to 15 minutes daily. After 26 weeks of follow up, both enzymes, serum 25(OH)D or Ca2+of all patients were measured by spectrophotometry. Data were analyzed by paired sample and independent sample ‘t' test. Results: The baseline plasma SOD (14.80±3.86U/ml vs 11.95±4.03U/ml) and CAT (11.0±7.59U/ml vs14.41±4.83U/ml) in study and control was almost similar (p>0.05). However, the mean SOD (18.98±2.98U/ml) and CAT (32.75±9.70U/ml) significantly increased (p<0.01; p<0.001) after 26 weeks of follow up only in ‘Study' patients. In addition, both enzymes were significantly (p<0.001) higher in the D3 supplemented patients than those of placebo treated patients after 26 weeks of follow up. Conclusion: The present study reveals that vitamin D3 supplementation increases the plasma antioxidant enzymes in D3 deficient patients with COPD.