Regularly eating probiotics found in yoghurt or food supplements, may help lower blood pressure.
Live bacteria and yeasts, often known as 'friendly bacteria', were shown to modestly lower blood pressure when taken for two months or more in a review published in the American Heart Association journal Hypertension.
Researchers examined nine studies involving 543 adults with both normal and raised blood pressure.
The found that consuming probiotics lowered systolic blood pressure - the highest blood pressure reading when the heart beats - by an average 3.56 millimetres of mercury (mm Hg).
Diastolic blood pressure --the lowest level blood pressure reaches as the heart relaxed between beats - was lowered by an average 2.38 mm Hg, compared to adults who didn't consume probiotics.
Probiotics with multiple bacteria were more effective at lowering blood pressure than those with a single bacteria. The concentration of bacteria in a dose also affected results.
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Around 30% of people in England have high blood pressure but many don't know it, says the NHS. If left untreated, high blood pressure increases the risk of a heart attack or stroke.
Dr Jing Sun, lead author and senior lecturer at Griffith University, Queensland, Australia, said: "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 said.
"This includes probiotics in yoghurt, fermented and sour milk and cheese, and probiotic supplements."
She said further studies were needed before doctors could confidently recommend probiotics for controlling and preventing high blood pressure.