Harvard Heart Letter

Probiotics may lower blood pressure

Image: Thinkstock

Probiotics, the live bacteria found in yogurt, other fermented dairy or soy foods, and dietary supplements, are well known for their ability to calm diarrhea and boost the immune system. Now researchers are zeroing in on other health benefits these microorganisms may offer.

An article in the July 21, 2014, Hypertension analyzed the results of nine high-quality studies that looked at the effects of probiotics on blood pressure. The 543 participants, who included adults with normal and high blood pressure, had modest drops in both systolic (top number) and diastolic (bottom number) blood pressure. The people who showed the greatest reduction were those with elevated blood pressure (130/80 mm Hg or above). Participants who consumed foods or supplements with large concentrations of bacteria, or several different strains, saw the greatest improvement. But it took eight weeks or longer for the benefits to show up.

Possible explanations for the effect include probiotics' ability to lower cholesterol, triglycerides, and blood sugar levels. Dairy products with probiotics may also contain substances that are similar to the makeup of ACE inhibitor medicines, used to control blood pressure.