Eighty-six patients with prehypertension or stage 1 hypertension (systolic blood pressure of 130 - 159 mm Hg) were randomly assigned to receive, in double-blind fashion, 1 capsule per day of nattokinase (2,000 fibrinolytic units per capsule) or placebo for eight weeks. Compared with placebo, nattokinase significantly decreased mean systolic and diastolic blood pressure by 5.5 mm Hg (p<0.05) and 2.84 mm Hg (p<0.05) respectively.
Comment from Alan Gaby, MD
Nattokinase is a fibrinolytic enzyme found in natto (fermented soybens). The results of the present study indicate that nottokinase is an effective treatment for mild hypertension. While nattokinase treatment decreased plasma renin activity to some extent, it had no effect on angiotensin-converting enzyme activity. Therefore, the mechanism of action of nattokinase as an antihypertensive agent is not clear. Although it is a fibrinolytic enzyme, nattokinase does not appear to cause abnormal bleeding. It is not known, however, whether it is safe to administer nattokinase to people taking anticoagulant or platelet-inhibiting medications.
Kim JY, et. al. Effects of nattokinase on blood pressure: a randomized, controlled trial. Hypertens Res. 2008:31:1583-1588.
Reprinted with exclusive permission of Townsend Letter - June 2009.