Kefir is a milk-based drink made by adding kefir grains — whitish grains obtained through the fermentation of specific bacteria and yeast — that allow it to obtain the specific creamy thickness and slightly sour taste.
This probiotic drink has traditionally been tied to numerous benefits — especially its wholesome effects on the gut microbiome and digestion.
But now we know that the bacteria in our guts influence more than just a good digestion.
The microorganisms that populate our guts have been shown to communicate with the brain, which gives them the potential to influence plenty of processes in our body.
A study from last year even showed that people with coronary heart disease exhibited differences in the composition of their gut microbiota, compared with people without this condition.
Probiotics to the rescue?
Another paper, this one published in the journal Nature, noted that a well-balanced gut microbiome could protect against high blood pressure, though the underlying biological mechanisms through which it is able to accomplish this remained unclear.
Yet this discovery led the study’s authors to hypothesize that we could wield probiotic supplements as a weapon against hypertension, as they would promote healthful bacterial diversity.
“I think,” said one of the scientists, “certainly there’s some promise in developing probiotics that could be targeted to possibly fixing some of the effects of a high-salt diet [responsible for high blood pressure].”
However, researchers at Auburn University in Alabama and the University of Vila Velha in Espirito Santo, Brazil, are taking the question closer to home.
In a recent study, they worked with a rat model to see whether kefir’s probiotic properties would influence gut health and help to lower blood pressure.
Their findings were presented earlier this week at the annual Experimental Biology conference, held in San Diego, CA.
From gut to brain to cardiovascular system
In order to see whether, and how, a diet that consistently integrated kefir would influence blood pressure, the team — which was led by Mirian Silva-Cutini, of Auburn University — worked with three different groups of rats:
- Those in the first group had high blood pressure, and they were given kefir on a regular basis for a period of 9 weeks.
- Those in the second group also had high blood pressure, but they were not given kefir.
- Those in the third group had no blood pressure problems, and they were not given kefir (the controls).
After the 9-week period, stool and blood samples were taken taken from all the rats in order to establish which changes had — or had not — occurred in their gut microbiota, and to test for specific toxins that might be released by some bacteria.
Blood pressure was also measured, and the team used “immunofluorescence” to look at patterns of neural changes in the hypothalamus. This region of the brain plays an important role in regulating some basic processes in the body, including blood pressure.
Silva-Cutini and colleagues discovered that the rats who had regularly been consuming kefir for 9 weeks exhibited lower levels of endotoxins, which are harmful substances that are a byproduct of bacterial disintegration. Endotoxins are known to contribute to inflammation.
The same rats also presented lower blood pressure and had an improved intestinal structure, as the permeability — that is, how easily various microbes and substances can leak into the system — of the intestines was lowered.
Another finding was that kefir-drinking rats had regained the balance of helpful bacteria in the gut microbiota, and the level of inflammation in their central nervous systems was reduced.
The results indicate that kefir’s effect on gut bacteria is reflected in the kinds of signals transmitted by the brain to the rest of the system. Thus, a balanced gut microbiome appears to influence the brain to lower blood pressure to healthy levels.
“Our data suggests that kefir antihypertensive-associated mechanisms involve gut microbiota-brain axis communication during hypertension,” the researchers conclude.