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.
The 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
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
In order to forecast
the cardiovascular events, the experts assessed TMAO levels in about 4,007
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.