Could good gut bacteria help prevent cardiovascular disease?

From improving cognitive function​, to aiding in the prevention of colorectal cancer​, the importance of good gut health is only now truly being understood. And with that understanding has come the extraordinary rise of the gut health trend, leading to the creation and huge success of the gut health​ industry. In fact, it’s become so popular that gut health is now widely recognised as a go-to term for overall health and wellbeing.

This growing understanding of the importance of good gut health​, on overall health and wellbeing, has led to multiple research studies, looking to better comprehend the potential benefits. One such study, recently published in Cell Press, has sought to determine if the good bacteria in the gut microbiome could help to reduce the risk of developing cardiovascular disease.

What is the gut microbiome?​Each of us has trillions of microbes or bacteria living in our gut. These are collectively referred to as the gut microbiome. The two most common species of helpful bacteria found in our gut microbiome are Lactobacillus and Bifidobacteria. Maintaining a healthy balance between the helpful (good) bacteria and the unhelpful (bad) bacteria is fundamental in supporting a healthy digestive system, with the gut now understood to be central to health, containing more than 70% of our immune system.

The gut microbiome has been linked not just to gut health, but with the health of the entire body. The gut-brain axis or the communication between the gut and the brain​​ is one fundamental function currently being researched by scientists and also gaining widespread recognition amongst consumers. The gut-skin axis and the gut-liver axis are two other connections which are beginning to be studied and understood. Furthermore, gut health has also been linked to the prevention of colorectal cancer​​ and other chronic diseases.

Could good gut bacteria reduce the risk of developing cardiovascular disease?​The study, led by Dr Ramnik Xavier of the Broad Institute of MIT and Harvard, analysed bacteria in stool samples from more than 1,400 individuals. These results were part of a wider research programme conducted by the Framingham Heart Study.

What is the Framingham Heart Study?​The Framingham Heart Study is an ongoing cardiovascular cohort study of residents of the city of Framingham, Massachusetts. The study began in 1948 with 5,209 adult participants and is now on its third generation of participants. It’s conducted by the National Heart, Lung, and Blood Institute, in collaboration with (since 1971) Boston University.

Prior to the Framingham Heart Study, ​almost nothing was known about the epidemiology of hypertensive or arteriosclerotic cardiovascular disease. Much of the now-common knowledge concerning heart disease, such as the effects of diet, exercise, and common medications such as aspirin, is based on this study.

The team analysed the bacterial genomes (the complete sets of genes) in the stool samples. They also studied blood samples and cardiovascular health measurements from the participants to identify microbes and metabolic pathways associated with cardiovascular disease.

The research team identified several species of bacteria whose levels were associated with blood markers of cardiovascular disease. These markers included cholesterol, triglyceride, and blood glucose levels.

Higher levels of one group of bacteria called Oscillibacter were strongly associated with lower levels of cholesterol, both in the stool and blood samples. Oscillibacter were also linked with other blood markers of reduced cardiovascular risk, such as lower triglycerides and glucose and higher high-density lipoprotein.

According to the research team, the reductions in cholesterol by Oscillibacter appeared to be related to genes for enzymes, which break down cholesterol in the intestines. They determined that this could lead to less cholesterol making its way into the bloodstream.

To confirm that Oscillibacter could process cholesterol, the researchers grew several Oscillibacter strains from the stool samples and then fed them cholesterol. The bacteria took up the cholesterol and broke it down into smaller molecules that do not raise the risk of developing cardiovascular disease.

The team identified enzymes from other bacteria that were also associated with lower cholesterol levels. The team concluded that a detailed knowledge of the microbes and metabolic pathways, which affect the risk of developing cardiovascular disease, may eventually lead to personalised therapies that manipulate gut bacteria.

“Our research integrates findings from human subjects with experimental validation to ensure we achieve actionable mechanistic insight that will serve as starting points to improve cardiovascular health,” said Dr Xavier.

How to support good bacteria in the gut. GettyImages/PeopleImagesHow to support good bacteria in the gut​The consumption of foods rich in prebiotics, probiotics and postbiotics​ will support the growth of good bacteria in the gut.

What are prebiotics in food?​Prebiotics in food are compounds which support the beneficial microorganisms or good bacteria in the gut (gastrointestinal tract).

Dietary prebiotics are typically non-digestible fibre compounds that pass undigested through the upper part of the gastrointestinal tract, supporting the growth of the ‘good’ bacteria in the colon. They can be found in a multitude of foods, including almonds, bananas, wholegrain wheat, corn, rye and barley, and flaxseeds.

What are probiotics in food?​Probiotics in foods are live microorganisms, often described as helpful or ‘good’ bacteria, because they help keep the gut healthy. Probiotics are available in foods such as live yogurt.

What are postbiotics in food?​Postbiotics, also known as metabiotics, biogenics, or metabolites, are a waste product, produced when the body digests prebiotics and probiotics.

Healthy postbiotics include nutrients such as vitamins B and K, and amino acids. Postbiotics also produce antimicrobial peptides, known as host defence peptides, as they help to slow down the growth of harmful bacteria.

Postbiotics can also be found in fermented foods such as sauerkraut and fermented breads and buttermilk.

Could good gut bacteria help prevent cardiovascular disease? GettyImages/bojanstorySource: Gut microbiome and metabolome profiling in Framingham heart study reveals cholesterol-metabolizing bacteria
Published online: 2 April 2024
DOI: https://doi.org/10.1016/j.cell.2024.03.014
Authors: Chenhao Li, Martin Stražar, Ahmed M.T. Mohamed et al.