A red meat-heavy diet significantly increases levels of a gut bacteria that has been linked to the development of heart disease, according to a study published this week in the European Heart Journal. The research, led by Stanley Hazen, MD, Ph.D., builds upon previous research showing a high level of Trimethylamine N-oxide (TMAO)—a gut bacteria byproduct formed during digestion—is a powerful tool for predicting future heart attack, stroke, and death risks. The new study showed chronic red meat consumption enhanced the production of TMAO and reduced the kidneys’ efficiency of expelling it, compared to diets of non-animal protein sources. The study included 113 participants who were provided complete meals prepared using either red meat, white meat, or vegetarian protein sources that made up 25 percent of their daily calories. After one month, the vast majority of study participants on the red-meat diet experienced an elevation of three to ten times the level of TMAO. However, after patients stopped consuming red meat, TMAO levels subsided. “We know lifestyle factors are critical for cardiovascular health, and these findings build upon our previous research on TMAO’s link with heart disease,” Hazen said. “They provide further evidence for how dietary interventions may be an effective treatment strategy to reduce TMAO levels and lower subsequent risk of heart disease.”