Gut Bacteria Is Linked to Heart Attacks

A new study associates certain bacteria living in the gut with increased levels of coronary atherosclerotic plaques that play a role in causing heart attacks.

Gut microbiota, which are bacteria and other microorganisms living in the gastrointestinal tract, have been linked to several cardiovascular diseases, including atherosclerosis. The condition is defined by the narrowing of arteries, making it difficult for blood to flow through them. However, the relationship between gut microbiota and atherosclerosis is not well understood.

In a new study published in Circulation, researchers at Uppsala and Lund University, Sweden, analyzed gut bacteria and cardiac imaging among 8,973 participants aged 50 to 65 without previously known heart disease.

They found that the presence of oral bacteria, especially species from the Streptococcus genus, in the gut is associated with higher levels of atherosclerotic plaques in the heart's small arteries. Atherosclerotic plaques, which are formed by the build-up of fatty and cholesterol deposits, are one of the major causes of heart attacks.

"The large number of samples with high-quality data from cardiac imaging and gut flora allowed us to identify novel associations. Among our most significant findings, Streptococcus anginosus and S. oralis subsp. oralis were the two strongest ones," says Sergi Sayols-Baixeras, lead author from Uppsala University.

The researchers conducted large-scale deep characterization of bacterial communities in biological samples by sequencing the DNA content and comparing it to known bacteria sequences. Using imaging techniques, the researchers detected and measured early changes in the small vessels of the heart.

Some of the species associated with the build-up of fatty deposits in heart arteries were also linked to the levels of the same species in the mouth. In a previous study, these species were associated with worse dental health.

The researchers say long-term and experimental studies are necessary to determine how exactly bacteria in the gut affect atherogenesis.

The human digestive system contains over 100 trillion microbial cells that influence our physical and mental health.

For example, an imbalance of good and bad microbes in the gut, called gut dysbiosis, may contribute to weight gain. The microbiota can also play a role in developing intestinal illnesses, such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS).

At the same time, gut microbiota can help to promote "good" cholesterol and control blood sugar.

Increasing evidence associates imbalance and inflammation of the gut microbiota with several mental illnesses, such as anxiety and depression. Meanwhile, a recent study suggests that specific strains of certain gut bacteria are likely to cause Parkinson's disease.

As microbiota imbalance may play a major role in developing chronic diseases, it is important to take care of gut health.