Probiotics may help protect against high blood pressure

A study conducted by researchers at MIT suggests that microbes in a probiotic could reverse the effects of a high-salt diet and protect against high blood pressure.

The study, “Salt-responsive gut commensal modulates TH17 axis and disease,” was published in Nature.

The MIT team, working with researchers in Germany, found that a high-salt diet shrinks the population of beneficial gut bacteria. As a result, pro-inflammatory immune cells called Th-17, which have been linked to high blood pressure, grow in number.

During the two-week study, the researchers fed mice a diet made up of 4% sodium chloride compared with 0.5% for mice on a normal diet. They found that the high-salt diet led to a drop in Lactobacillus murinus bacteria and a rise in the populations of inflammatory Th-17 cells, as well as an elevation in blood pressure. When mice experiencing high blood pressure were given a probiotic containing Lactobacillus murinus, Th-17 populations went down and hypertension was reduced.

In a study of 12 human subjects, the researchers found that adding 6,000 mg of sodium chloride per day to the subjects’ diet also changed the composition of bacteria in the gut. Populations of lactobacillus bacteria went down, and the subjects’ blood pressure went up along with their Th-17 cell counts. When subjects were given a commercially available probiotic for a week before going on a high-salt diet, their gut lactobacillus levels and blood pressure remained normal.

It is still unclear exactly how Th-17 cells contribute to the development of high blood pressure and other ill effects of a high-salt diet. However, the researchers hope that their findings, along with future studies, will help to shed more light on the mechanism by which a high-salt diet influences disease.