Link between gut bacteria, diet, and blood clots

Last Updated: 2017-04-24

By Will Boggs MD

NEW YORK (Reuters Health) - Gut bacteria take choline, a vitamin-like nutrient, and convert it into a chemical that increases the risk of life-threatening blood clots, researchers report.

Dr. Stanley L. Hazen and associates from the Cleveland Clinic in Ohio had earlier shown that gut bacterial production of TMAO (trimethylamine N-oxide) from choline and other dietary nutrients contributed to the development of cardiovascular disease and that high levels of TMAO in the blood were associated with an increased risk of thrombosis.

In the current study, they gave oral choline supplements to 18 volunteers, including eight vegans/vegetarians, and then measured TMAO levels, along with platelet responsiveness.

After taking the supplements for up to two months, the participants showed more than 10-fold increases in blood levels of TMAO. They also showed significant increases in platelet responsiveness that were directly related to the TMAO level.

Aspirin reduced both the increases in TMAO and the increases in platelet clotting associated with choline, but it didn't completely eliminate them, according to the report online April 24 in Circulation.

The researchers can't say for sure why aspirin reduced the increases in TMAO, but they note that aspirin has been reported to alter the makeup of the gut microbiome.

The findings are of particular concern in people at high cardiovascular risk, whose increased risk of blood clots may not be overcome by low-dose aspirin. The researchers recommend further study.

They also say it's worth exploring whether low-dose aspirin is beneficial in otherwise healthy people with elevated TMAO.

Dr. Herbert Tilg from Medical University Innsbruck, Austria, who has studied the link between gut microbes and thrombosis, told Reuters Health, “This and earlier studies show that we now definitely have to consider dietary aspects in this context, i.e., diet drives thrombosis risk.”

“These associations are totally new and unexpected: a link between diet - gut microbiota - and thromboembolic events,” he said. “They are extremely relevant for the public and in medicine, as these are very very common and often fatal (pulmonary embolism).”

Dr. Tilg added that “preventive strategies are needed, and probably aspirin is not sufficient. This needs further studies.”

Dr. Hazen did not respond to a request for comment.

SOURCE: http://bit.ly/2q7Ru3k

Circulation 2017.