Lowering of body iron stores by blood letting and oxidation resistance of serum lipoproteins: a randomized cross‐over trial in male smokers

Abstract

Objectives. The purpose of this study was to test the hypothesis that the reduction of body iron stores by venesection (blood letting) would reduce the susceptibility to oxidation of atherogenic serum lipoproteins. Design. This is a randomized, controlled cross‐over trial in 14 regularly smoking men with elevated serum ferritin concentration. The study design comprised two 14‐week study periods, with a 14‐week wash‐out period in between, with either blood donations or control. Setting. The study site was the Research Institute of Public Health, University of Kuopio. Investigators from the Division of Epidemiology, University of Minnesota, Minneapolis, participated in the planning of the study. Subjects. Fourteen volunteers who were heavy smokers and had previous experience in blood letting were recruited for the study. Interventions. During the intervention periods, the subjects donated 450 mg (500 mL) of blood three times in 14 weeks. Main outcome measurements. Oxidation resistance of very low density lipoprotein (VLDL)/low density lipoprotein (LDL) was measured after inducing oxidation with haemin and H₂O₂. Results. Serum ferritin concentration was reduced by 44% [95% confidence interval (CI) 8–82%, P = 0.021] during the venesection periods, the maximal oxidation velocity was decreased by 20% (95% CI 3–30%, P = 0.032), and the lag time to start of oxidation was lengthened (oxidation resistance increased) by 33% (95% CI 1–64%, P = 0.036). Conclusions. These observations indicate that the reduction of body iron stores by venesection can increase the oxidation resistance of serum VLDL/LDL in regularly smoking men.