By Cari Nierenberg, Contributing writer
Published: 07/22/2014 10:34 AM EDT on LiveScience
People who consume beneficial bacteria — whether they eat foods such as yogurt, or take probiotic supplements — may modestly reduce their blood pressure, a new study suggests.
An analysis done by researchers in Australia found that people in randomized, controlled studies who regularly ate foods containing large amounts of live bacteria or who took probiotic supplements reduced their blood pressure during the studies more than the control groups. People who took probiotics reduced their systolic blood pressure (the top number in a reading) by an average of 3.56 millimeters of mercury, and their diastolic blood pressure (the second number) by an average of 2.38 millimeters of mercury, more than the study participants who were not consuming probiotics.
"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," said study author Jing Sun, a senior lecturer in biostatistics at the Griffith University School of Medicine in Queensland, Australia. "They can also help maintain healthy blood-pressure levels." [8 Tips to Be a Probiotic Pro]
The modest blood-pressure reductions from probiotics shown in this analysis were comparable to results seen in review studies of people who reduced their salt intake to less than 2,000 milligrams of sodium per day, and those in people who began a regular strength-training program, the researchers said.
The findings are published online today (July 21) in the journal Hypertension.
Bacteria and blood pressure
For the review, researchers evaluated data collected from nine previously published, high-quality studies that examined the effect of probiotics in a total of 543 adults who had normal or high blood pressure. Most of the trials were small and involved people who got healthy bacteria from eating foods such as yogurt, fermented dairy drinks or cheese. One study involved people who took a probiotic supplement, given in a capsule form.
The analysis did not look at whether getting probiotics from food was better at reducing blood pressure than getting good bacteria from supplements. But the data did show that people needed to consume probiotics for at least eight weeks to see improvements in blood pressure.
There is still a lot of work that needs to be done to identify which probiotic strains are best for reducing blood pressure, Sun said. However, the findings revealed that people who consumed one probiotic supplement capsule containing between 109 and 1012 colony forming units (CFU) daily can achieve good results, she said.
Only two of the nine trials reported that some people had mild side effects, typically gas or flatulence, from consuming probiotics.
It's not clear exactly how these bacteria might lower blood pressure, the researchers said. One possibility is that probiotics may help improve total and LDL cholesterol levels. Another theory is that a healthy community of gut bacteria may help to regulate hormones involved in controlling blood pressure and fluid balance in the body.
More studies, with more participants and done for a longer duration, are needed to determine how probiotics may benefit people who use them to prevent or control high blood pressure, the researchers said.
Probiotics would be used in addition to — and not instead of — any prescribed blood-pressure medication, Sun said.