'Gut Reaction' May Predict Heart Risk
Higher levels of stomach substance called TMAO linked to heart attack, stroke, study suggests
In this study, published in the April 25 issue of the New England Journal of Medicine, Hazen's team collected data on TMAO levels from more than 4,000 patients and followed them for three years on average.
As TMAO levels increased so did the risk for heart attack, stroke or heart disease, the investigators found. Those with the highest levels of TMAO had 2.5 times the risk for these outcomes compared to those with the lowest levels of TMAO, the study authors reported.
Dr. Gregg Fonarow, a spokesman for the American Heart Association and professor of cardiovascular medicine and science at the University of California, Los Angeles, said that "there has been increasing interest in the role that intestinal microbial metabolism can play in metabolic and cardiovascular diseases."
Recent studies have suggested that TMAO may play a role in the initiation and progression of atherosclerosis (a harmful buildup of sticky plaque in the arteries), he said.
Noting that intestinal metabolism influences production of this metabolite, Fonarow said "these findings raise the possibility that modulating intestinal microbe metabolism to decrease TMAO production could be therapeutic."
But more research is needed, he added. "Whether TMAO is just a marker of cardiovascular risk or turns out to be an actual mediator and hence a promising target for cardiovascular prevention and treatment will require further study," Fonarow said.
Dr. Joseph Loscalzo, from Brigham and Women's Hospital and Harvard Medical School in Boston, writes in an accompanying journal editorial that the findings suggest a host of possible novel strategies for preventing heart disease. Besides limiting consumption of choline-rich foods, he said these might include use of probiotics to alter microbiota in the gut.
Although the study found an association between higher levels of TMAO in the blood and increased risk of cardiovascular problems, it did not prove a cause-and-effect relationship.