Probiotics are products containing the "friendly" bacteria that normally inhabit the human intestinal tract, where these beneficial microbes help complete the digestive process. Some of these microbes actually produce vitamins, and evidence suggests that without them, the immune system doesn't function optimally, compromising resistance to infection. The latest word on probiotics is that they may also help lower blood pressure. A new analysis of nine earlier randomized controlled trials found that regularly taking probiotics led to reductions in systolic blood pressure (the top number) by an average of 3.56 millimeters of mercury and diastolic pressure by 2.38. While these changes aren’t dramatic, the Australian research team that conducted the review concluded that bigger reductions may occur in people who already have high blood pressure (some of the study participants had normal blood pressure to begin with) Greater benefits might also be possible using probiotics that provide larger quantities of helpful bacteria or multiple species, or when people take probiotics for more than two months, as was the case in the studies reviewed. Positive effects from probiotics on diastolic blood pressure were greatest in people whose blood pressure was equal to or greater than 130/85, which is considered elevated. The probiotics used in the studies were primarily strains of Lactobacillus in dairy products. The study authors concluded that more research is needed before doctors can confidently recommend probiotics for control and prevention of high blood pressure.
Jing Sun et al, “Effect of Probiotics on Blood Pressure - A Systematic Review and Meta-Analysis of Randomized, Controlled Trials,” Hypertension, doi: 10.1161/ HYPERTENSIONAHA.114.03469