Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosisKoeth R.
A. et al (2013)A high level of meat consumption is known to be linked to the risk of developing cardiovascular disease (CVD) which is the number one cause of death globally. The common thinking was that the high levels of saturated fats and cholesterolwithin the meat were the cause of the risk increase; however recent analyses of studies suggest that there is in fact no association between these factors and CVD. This is problematic as without a clear link there is no way of introducing the desired effect of lower CVD risk. Atherosclerosis is the leading cause of CVD therefore identifying a cause for atherosclerosis is immensely impactfulin reducing risk of developing CVD.
Knowing this importance of atherosclerosis and that there is no association between high levels of saturated fats or cholesterol to CVD risk, new investigations took place – an investigation on the effect of human microbiota on atherosclerosis providedsignificant results. Human microbiota is an area of study that is gaining more and more exposure as time goes on, this is because of recent realizations of the importance microbes can have within the body – some researchers even claim that health in humans may be more impacted by microbes than genes or the environment. One of the regions of the body that contains a vast and varied microbiota is the gut. Research into the composition and activity of gut microbiota has proved valuable as there have been many findings that express the microbiota can lead to changes in human health.
This paper provides useful insight into how microbes affecthealth by specifically looking into the mechanism of intestinal microbiota (part of the gut microbiota) metabolism and its effect on atherosclerosis. The metabolism by intestinal microbiota is shown to promote atherosclerosis therefore indicating it as a cause in developing CVD.Using mice studies, the authors show that metabolization of L-carnitine (a trimethylamine (TMA) abundant in red meat)by intestinal microbiota produces trimethylamine-N-oxide (TMAO) which is atherogenic meaning it promotes atherosclerosis. This accelerated atherosclerosis in the mice, suggesting that it is the L-carnitine present in red meat that causes the risk in development of CVD. Further findings from the authors’ indicate that the dietary habits of an individual could actually influence the intestinal microbiota’s capacity to generate TMAO from L-carnitine, as omnivorous humansgenerated more TMAO than vegans or vegetarians even though they ingested the same amount of L-carnitine.
An explanation for this variance in TMAO generation levels is that dietary habits also alter the intestinal microbiota composition, with meat eaters being able to generate more TMAO than vegans or vegetarians thus seemingly putting them at higher risk of developing CVD.From these findings a link between high levels of meat consumption and the risk of developing CVD can clearly be seen and a new cause for the increase of CVD risk has potentially been found. Therefore responses can be put intoaction to lower the risk, such as a change in diet or perhaps finding a way to suppress the specific intestinal microbes thatmetabolises TMAs.
When the older link between saturated fats/cholesterol and the risk of developing CVD was disproven, the study of the human microbiota uncovered a new link expressing the great potential microbiota studies can achieve.