In a word – yes. The kind of bacteria we carry in our intestines (also called the microbiome) could affect our risk of heart disease, according to existing studies. An excellent Viewpoint article from the Journal of the American Medical Association (JAMA) summarizes key points:
1. Gut bacteria affect our risk of obesity (as blogged previously)
2. Our microbiome has an influence on our risk of developing type 2 diabetes. This occurs through effects on appetite hormones, insulin resistance, and making the gut more permeable (‘leaky gut’), resulting in activation of the immune system, low grade inflammation, and insulin resistance.
3. Cholesterol – gut bugs can decrease the rate of bile acid synthesis, which require cholesterol in their production, resulting in increased levels of bad cholesterol (LDL).
4. Inflammation (as above) enhances plaque progression and rupture.
5. Relaxation of our blood vessels, which is an important part of their normal function, can be impaired by certain types of gut and mouth bugs which interfere with nitric oxide signalling and produce hydrogen sulphide gas, leading to endothelial dysfunction.
6. Some gut bugs produce a volatile gas from some foods called TMA, which leads to increased clotting of platelets and inflammation (though the data on whether TMA leads to narrowing of the arteries are controversial and not clear).
Caveats:
The authors note that a lot of this data comes from animal data, which cannot necessarily be extrapolated to human physiology.
They also point out that while we are gaining an early understanding of the effects of gut bacteria on metabolic disease, we are nowhere near establishing effective treatments – though there is much interest in probiotics, probiotics, and other approaches that may become tangible in the future.
They also point out that even less is known about the virome: the gut viruses that are ubiquitous and, like bacteria, capable of producing hormones that affect mammalian physiology.
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