Professor Andreas Michalsen of the Charite-University Medical Centre in Berlin and colleagues at the University Duisburg-Essen said donating blood can provide medical benefits for obese people with metabolic syndrome -- which includes insulin resistance, glucose intolerance, dyslipidemia and hypertension and leads to an increased risk of diabetes and cardiovascular disease. Accumulation of iron in the body is associated with hypertension and diabetes.
Michalsen and colleagues randomly assigned patients with metabolic syndrome into two groups, those undergoing iron reduction by phlebotomy -- bloodletting or cutting a vein -- and controls.
The iron-reduction patients had 300 milliliters of blood removed at the start of the trial and between 250 ml and 500 ml removed four weeks later. Six weeks later, the patients who gave blood had a significant reduction in systolic blood pressure -- from 148 mm Hg to 130 mm Hg -- as well as reduction in blood glucose levels and heart rate, and an improvement in cholesterol levels.
"Consecutive reduction in iron stores was able to improve markers of cardiovascular risk and glycemic control. Consequently blood donation may prevent not just diabetes but also cardiovascular disease for the obese," Michalsen said in a statement. "Obviously this treatment will not be suitable for people with anemia, but for those eligible for treatment blood donation may prevent escalation of their condition."