Wexler and Aukerman reported a significant dose dependent BP lowering effect when comparing doses of 300 mg all the way up to 1500 mg in divided doses daily (92).
Purple potatoes and hypertension:
Eighteen overweight and hypertensive men and women consumed 6-8 small microwaved purple potatoes twice a day, or no potatoes, for four weeks; then switch to the opposite regimen for another four weeks. The researchers monitored the volunteer’s blood pressure during the same period and found that the average diastolic blood pressure dropped by 4.3% and the average systolic dropped by 3.5%. None of the study participants gained weight during the study period. The study authors concluded that purple potato consumption may control blood pressure, reduce the risk of heart disease, and decrease stroke risk while not causing weight gain. (74)