Vinegar does NOT lower high blood pressure.
Though a few random studies have indicated that the acetic acid found in vinegar may reduce high blood pressure, scientific opinion does not support the claim citing insufficient human research in addition to acetic acid's quick absorption and clearance from the bloodstream making it highly unlikely to be effective at maintaining lower blood pressure.
Vinegar High Blood Pressure Study
In a study published in the journal Bioscience, Biotechnology, and Biochemistry, researchers set out to examine the effectiveness of dietary vinegar on hypertension. The study concluded that rats that were given dietary vinegar over a long period demonstrated marked lower pressure compared to the rats in the control study. The authors suggest that it is the acetic acid in vinegar that may have produced the effect. [Kondo, 2690]
Scientific Community Doubtful
Carol S Johnston, PhD, RD from the Department of Nutrition, Arizona State University does not support the vinegar blood pressure connection. In the article "Vinegar: Medicinal Uses and Antiglycemic Effect", published in the journal MedGenMed, after investigating the research she does not support the claim that vinegar has the ability to lower blood pressure citing the that no studies have established this fact in humans. [Johnston, 61]
The Authority Weighs In
Asked to substantiate the health claims that acetic acid is related to the maintenance of normal blood pressure, the European Food Safety Authority concluded that though a study showed an improvement in systolic blood pressure in rats, two human studies were conflicting and further added that the effectiveness of acetic acid on blood pressure is highly unlikely due to its rapid absorption from the circulation immediately after consumption. [EFSA Panel, 2199]