Probiotics are live microorganisms that occur naturally in the gut. These microorganisms are also present in some foods, such as live-cultured yoghurt, some fermented vegetables and aged cheeses.
Consumption of probiotic-rich foods - such as yoghurt - and dietary supplements of the "good" bacteria may help lower blood pressure, according to researchers.
Past research has suggested that probiotics are good for our health by aiding digestion, intestinal function and protecting against harmful bacteria.
Earlier this year, Medical News today reported on a study published in JAMA Pediatrics, which suggested that probiotic use among infants may reduce the risk of gastrointestinal disorders.
Such evidence has led to the addition of probiotics to certain foods, and they are also available as dietary supplements.
Now, research led by Jing Sun, PhD, of the Griffith Health Institute and School of Medicine at Griffith University in Australia, suggests that consuming probiotics from food sources and dietary supplements may improve blood pressure.
Probiotics 'may help reduce high blood pressure and maintain healthy blood pressure'
To reach their findings, Sun and his team analyzed nine high-quality studies that assessed the probiotic consumption of 543 adults who had either normal or high blood pressure.
They found that on average, participants who had consumed probiotics daily for 8 weeks or more had a 3.5 mm Hg lower systolic blood pressure (pressure in the arteries when the heart beats) and a 2.38 mm Hg lower diastolic blood pressure (pressure in the arteries between heartbeats), compared with those who did not consume probiotics.
Such effects were strongest among participants with high blood pressure - defined as 130/85 mm Hg or more - and greater benefits were found from consumption of probiotic products that contained multiple bacteria.
However, the researchers note that consumption of probiotics with fewer than 109 colony-forming units (CFU) - the level of bacteria or dose of probiotics in a product - did not improve blood pressure, nor did consumption of probiotics for less than 8 weeks.
Commenting on the team's findings, Sun says:
"The small collection of studies we looked at suggest regular consumption of probiotics can be part of a healthy lifestyle to help reduce high blood pressure, as well as maintain healthy blood pressure levels."
She hypothesizes that probiotics may have a beneficial effect on blood pressure through lowering cholesterol levels, reducing blood sugar levels and insulin resistance, and helping to regulate the hormone system that manages fluid balance and blood pressure.
Although these findings show promise for the use of probiotics in lowering blood pressure, Sun notes that doctors should not recommend them for blood pressure control until further studies have confirmed the benefits.
She also points out that the team's investigation is subject to limitations. "The studies looking at probiotics and blood pressure tend to be small," Sun says. "Moreover, two studies had a short duration of 3-4 weeks of probiotic consumption, which might have affected the overall results of the analysis."
This is not the only study to suggest that the benefits of probiotics reach further than the gut. Last year, Medical News Today reported on a study by researchers from the University of California-Los Angeles, which suggested probiotics could be beneficial for brain function, while other research found they could be effective against psoriasis and chronic fatigue syndrome.