“All diseases begin in the gut.”
– Hippocrates (460–370 BC)
Hippocrates knew what he was talking about, even back then! More and more evidence shows that our intestinal microbiota plays a role in our lifelong health. Plus, our diet is a major factor in maintaining an optimal balance of gut microbiota.
The human gut microbiome is dominated by five phyla: Bacteroidetes, Firmicutes, Actinobacteria, Proteobacteria, and Cerrucomicrobia. In a healthy gut, the groups that don’t need oxygen Bacteroidetes and Firmicutes contribute to more than 90% of the total bacterial species.
Factors believed to contribute to disease development:
- Unwelcome, disruptive changes in the composition of gut microbiota, known as “gut dysbiosis”. The changes have been linked to various health issues such as atherosclerosis, hypertension, heart failure, chronic kidney disease, obesity, and type 2 diabetes mellitus.
- The metabolic potential of gut microbiota/ the byproducts of their metabolism in response to various environmental stimuli, including what we eat. Our gut microbiome generates bioactive metabolites that can enter the bloodstream and impact us through various biochemical pathways.
There is a complex interplay between the gut microbiota, their metabolites, and the development and progression of cardiovascular diseases.
Gut microbiota, obesity, and cardiovascular diseases: The “heart-gut axis”
Recent studies have employed microbial sequencing analysis to discover the characteristic gut bacteria types associated with cardiovascular disease, particularly atherosclerosis and ischemic stroke.
The pathology of obesity is seen to be associated with changes in the relative population size of Bacteroides and Firmicutes, specifically with a higher number of Firmicutes. Animal studies show that the addition of “obese” microbiota combinations to the intestines of germ-free mice results in piling on more body fat than the addition of “lean” microbiota, on the same diet.
Gut microbiota is also implicated in the development of heart failure. In heart failure, there is a reduction in intestinal blood flow and low oxygen delivery, which unfortunately allows the growth of anaerobic, pathogenic bacteria in the gut. In addition, patients with chronic heart failure can develop edema in the bowel wall due to venous congestion. This damages the absorptive function of the intestine and encourages unfavorable bacterial overgrowth in the mucus layer.
The harmful compounds produced by these bacteria lead to predisposition or worsening of heart failure conditions.
Age as a factor in gut microbial changes and heart disease
The role of oxidative stress and inflammation in making arteries unhealthy over time is well known. Recent studies in animal models have been aimed at finding the cause or trigger for the inflammation. With age, the gut microbiota begins producing toxic molecules that enter the bloodstream, setting off a loop of inflammation, oxidative stress, and tissue damage.
Dietary changes for gut--- and heart health
The role of diet in warding off heart disease just got more important. Scientists suggest altering diet to change the types and numbers of gut microbes and target the chemicals they produce. For instance, when we reduce red meat, we reduce the intake of choline and lecithin, which lowers the risk of heart disease. In addition, the Mediterranean diet has been shown to also reduce the risk of heart disease. Furthermore, probiotics have been suggested as an option to alter the microbiome and bring about a more balanced bacterial population. New research also suggests that heart failure patients who increase their dietary fiber intake tend to have healthier gut bacteria and a lowered risk of death or need for a heart transplant.
Just one more reason to keep our microbiome in top shape!