Researchers are looking at a surprising part of the body to find clues about heart disease. New studies focused on the gut—gut microbes specifically—show a complex link between diet and cardiovascular disease that is not as simple as calorie and fat counts.
Cardiovascular disease (CVD) is the leading killer worldwide. Behaviors like smoking, lack of exercise and poor diet have long been considered risk factors. Current research is putting a new spin on how what we eat affects heart health.
“Over the past decade we have increasingly begun to appreciate the ecological diversity of microbes living symbiotically within us…,’ says Stanley L. Hazen, MD, PhD, and W.H. Wilson Tang, MD, both of the Cleveland Clinic. They coauthored “The contributory role of gut microbiota in cardiovascular disease”, published in the Journal of Clinical Investigation.
“This Review summarizes many recent developments in our understanding of the contributory role of gut microbiota as an active participant, through this endocrine function, in the development of atherosclerosis and its adverse complications of CVD,” they say.
Trimethylamine (TMA), Trimethylamine-N-oxide (TMAO) and CVD
Gut microbial-derived metabolites, TMA and TMAO, are associated with high incidence of CVD. Inset: High TMAO plasma levels and incidence of myocardial disease or death. Image from Yamashita et al.
Their research looks at TMA and TMAO, byproducts of digestion and precursors to hardening of the arteries.
We eat foods that contain certain nutrients including choline and another called L-carnitine. Choline is an essential nutrient, vital for metabolism, fat transport and other key functions. Foods high in choline and L-carnitine include red meat, liver, and egg yolks.
Gut microbes have special enzymes to break down these nutrients, releasing TMA in the process. TMA is then converted by the body into TMAO. The role of microbes in this process has been confirmed in both animal—germ free mice—and human studies.
Hazan and Tang noted strong evidence for the link between TMAO and CVD, including the fact that “…elevated TMAO levels predicted major adverse cardiac events such as death, myocardial infarction, and stroke over a 3-year period.”
The possibility that gut microbes may offer potential new therapeutic opportunities for treating cardiovascular disease is being investigated at the Kobe University Graduate School of Medicine. They summarized their work and that of others in “Intestinal Immunity and Gut Microbiota as Therapeutic Targets for Preventing Atherosclerotic Cardiovascular Diseases”, which was recently published in the Circulation Journal. Their work suggested that a “characteristic flora type” could be linked to CVD.
KimberlyHatfield