Gut spills heart secrets

Bacteria in intestine can aid clogging of arteries

By Smriti Sharma
Published: Sunday 15 May 2011

imageRESEARCHERS have found a new culprit of cardiovascular diseases—gut flora. The bacteria present in the intestine help in the metabolism of fats and carbohydrates setting off a chain of reactions which lead to the development of plaque. Its accumulation clogs the arteries which finally becomes the cause of cardiac disorders.

The study, conducted by the department of cell biology at Cleveland Clinic in Ohio, USA, was published in the April 7 issue of Nature. To establish gut flora’s role in cardiovascular diseases, a team of researchers first compared the blood plasma of patients who had suffered a heart attack with those of healthy people.

In heart patients, one of the three metabolites of dietary lipid phosphatidylcholine was found very high. Trimethylamine N-oxide (TMAO), the metabolite, was identified as the culprit behind heart diseases. The other two metabolites are choline and betaine. To study how gut flora is responsible in the breakdown of dietary lipids, researchers administered choline-rich diet on mice that were genetically prone to heart disease. When choline breaks down, it produces TMAO.

Results of the study showed that the mice had developed atherosclerosis—a condition in which the artery wall thickens due to increased fatty materials such as cholesterol. When they eliminated gut flora from the intestine of mice using antibiotics, their arteries did not get clogged. Researchers, however, are not sure which type of gut bacteria is involved in plaque formation.

Choline is a major breakdown product of dietary fat. But it is also an essential nutrient. “Cutting it down completely from the diet is not advisable,” says Seema Gulati, chief project officer (nutrition) at the National Diabetes, Obesity and Cholesterol Foundation in Delhi. Appropriate use of pro-biotics or anti-bacterial drugs that hamper growth of intestinal micro-organisms may help manage the problem, the study suggests.

“The research has added choline and gut bacteria to the list of culprits responsible for the development of cardiovasculat diseases. The hypothesis requires an intensive study to formulate therapautic intervention because blocking choline or liver enzymes is not advisable,” says Anoop Misra, chairman of Fortis Centre of Excellence for Diabetes, Obesity, Metabolic Diseases and Endocrinology in Delhi.

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