Dr Andreas Michalsen and colleagues from Immanuel Hospital, Berlin, studied 33 patients who had blood removed and 31 controls.
Patients in the intervention group had 300ml of blood taken at the start of the study and 250–500ml more removed after four weeks.
Six weeks later, BP in patients who had blood removed was on average 16.6mmHg lower than in controls. Blood glucose, HbA1c and cholesterol levels were also all reduced.
The researchers said: ‘Adequately controlled phlebotomy could be considered as a cost-effective additional treatment option in metabolic syndrome’.