A microbial byproduct of gut bacteria contributes to heart diseases and may be used as a valuable tool to predict risk of heart attack, stroke and even death, according to a study from Cleveland Clinic's Lerner Research Institute.
Gut bacteria convert food into chemical compounds known as Trimethylamine N-oxide (TMAO) when one of the nutrients in the food is lecithin. Lecithin is abundantly found in foods such as eggs (especially egg yolk), dairy products, meats, soy products, and in small amounts in vegetables such as cauliflower, cabbage and peas.
AdvertisementThe TMAO affects metabolism of cholesterol in the liver, in the intestines, and in artery walls.
The presence of TMAO results in deposition of cholesterol and hampers the removal of cholesterol from arterial walls and peripheral cells. If the accumulated cholesterol detaches from the artery, it can obstruct the artery and can result in heart attack or stroke.
Thus gut bacteria can be responsible for occurrence of heart attacks in individuals with no probable factors for heart ailments such as increased levels of cholesterol.
Stanley Hazen and W.H. Wilson Tang at the Cleveland Clinic's Lerner Research Institute conducted a study on lab mice. The study findings were published in the New England Journal of Medicine.
40 healthy mice were given two hard boiled eggs, rich in lecithin, a fatty substance.
After eating eggs, the blood samples of the mice showed high levels of TMAO.
The researchers noted that if antibiotics were given to the mice before eating boiled eggs to suppress the gut bacteria, their blood TMAO levels decreased because antibiotics kill gut bacteria responsible for TMAO production.
Dr. Stanley Hazen, the lead researcher of this study and a renowned cardiologist at the Cleveland Clinic, said, "This showed that intestinal bacteria are essential for forming TMAO."
In order to forecast the cardiovascular events, the experts assessed TMAO levels in about 4,007 heart patients.
They discovered that increased levels of TMAO were indicative of stroke, heart attack and death within three years of follow up.
It was also seen that during the study the volunteers who died due to heart attack or stroke had high levels of TMAO than others.
These results are similar to those from another study by Hazen where species of gut bacteria called Acinetobacter converts dietary carnitine into TMAO. Carnitine is a substance found in red meat.
In other words, heart patients having high levels of TMAO were twice more vulnerable to the risk of stroke or heart attack as compared to those who were in the bottom quartile.
Even people without any cardiovascular ailment but with high levels of TMAO were 1.8 times more susceptible to be affected by cardiovascular event as compared to those who had low levels of TMAO.
The experts were of the opinion that TMAO levels can serve as an indicator for forecasting heart attack. However further researches are needed to establish the relationship.