News | Cardiac Diagnostics | January 23, 2019

Frequent Red Meat Consumption Triples Levels of Chemical Associated With Heart Disease

Findings of new study reveal tripling of blood levels of TMAO from red meat diet, but dietary effects can be reversed

Frequent Red Meat Consumption Triples Levels of Chemical Associated With Heart Disease. Photo from Pixabay https://pixabay.com/

Photo from Pixabay https://pixabay.com/

January 23, 2019 — Researchers have identified another reason to limit red meat consumption: high levels of a gut-generated chemical called trimethylamine N-oxide (TMAO) that is also linked to heart disease. Scientists found that people who eat a diet rich in red meat have triple the TMAO levels of those who eat a diet rich in either white meat or mostly plant-based proteins, but discontinuation of red meat eventually lowers those TMAO levels.

TMAO is a dietary byproduct that is formed by gut bacteria during digestion and is derived in part from nutrients that are abundant in red meat. While high saturated fat levels in red meat have long been known to contribute to heart disease — the leading cause of death in the United States — a growing number of studies have identified TMAO as another culprit. Until now, researchers knew little about how typical dietary patterns influence TMAO production or elimination.

The findings suggest that measuring and targeting TMAO levels — something doctors can do with a simple blood test — may be a promising new strategy for individualizing diets and helping to prevent heart disease. The study was funded largely by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health. It was published Dec. 10 in the European Heart Journal, a publication of the European Society of Cardiology.[1]

“These findings reinforce current dietary recommendations that encourage all ages to follow a heart-healthy eating plan that limits red meat,” said Charlotte Pratt, Ph.D., the NHLBI project officer for the study and a nutrition researcher and deputy chief of the Clinical Applications and Prevention Branch, Division of Cardiovascular Sciences, NHLBI. “This means eating a variety of foods, including more vegetables, fruits, whole grains, low-fat dairy foods, and plant-based protein sources such as beans and peas.”

“This study shows for the first time what a dramatic effect changing your diet has on levels of TMAO, which is increasingly linked to heart disease,” said Stanley L. Hazen, M.D., Ph.D., senior author of the study and section head of preventive cardiology and rehabilitation at the Cleveland Clinic. “It suggests that you can lower your heart disease risk by lowering TMAO.”

Hazen estimated that as many as a quarter of middle-aged Americans have naturally elevated TMAO levels, which are made worse by chronic red meat consumption. However, every person’s TMAO profile appears to be different, so tracking this chemical marker, Hazen suggested, could be an important step in using personalized medicine to fight heart disease.

For the study, researchers enrolled 113 healthy men and women in a clinical trial to examine the effects of dietary protein — in the form of red meat, white meat or non-meat sources — on TMAO production. All subjects were placed on each diet for a month in random order. When on the red meat diet, the participants consumed roughly the equivalent of about 8 ounces of steak daily, or two quarter-pound beef patties. After one month, researchers found that, on average, blood levels of TMAO in these participants tripled, compared to when they were on the diets high in either white meat or non-meat protein sources.

While all diets contained equal amounts of calories, half of the participants were also placed on high-fat versions of the three diets, and the researchers observed similar results. Thus, the effects of the protein source on TMAO levels were independent of dietary fat intake.

Importantly, the researchers discovered that the TMAO increases were reversible. When the subjects discontinued their red meat diet and moved to either a white meat or non-meat diet for another month, their TMAO levels decreased significantly.

The exact mechanisms by which TMAO affects heart disease is complex. Prior research has shown TMAO enhances cholesterol deposits into cells of the artery wall. Studies by the researchers also suggest that the chemical interacts with platelets — blood cells that are responsible for normal clotting responses — in a way that increases the risk for clot-related events such as heart attack and stroke.

TMAO measurement is currently available as a quick, simple blood test first developed by Hazen’s laboratory. In recent published studies, he and his colleagues reported development of a new class of drugs that are capable of lowering TMAO levels in the blood and reducing atherosclerosis and clotting risks in animal models, but those drugs are still experimental and not yet available to the public.

Read the article "Researchers Find Link Between Allergen in Red Meat and Heart Disease"

For more information: www.academic.oup.com/eurheartj

Reference

1. Wang Z., Bergeron N., Levison B.S., et al. Impact of chronic dietary red meat, white meat, or non-meat protein on trimethylamine N-oxide metabolism and renal excretion in healthy men and women. European Heart Journal, Dec. 10, 2018. https://doi.org/10.1093/eurheartj/ehy799

Related Content

With the advent and optimization of nuclear scintigraphy protocols using bone-avid radiotracers, cardiac amyloidosis caused by transthyretin protein (ATTR) can now be diagnosed noninvasively without a costly tissue biopsy. The radiotracer 99mTc-pyrophosphate (99mTc-PYP) binds to deposited ATTR amyloid fibrils in the myocardium and can be visualized using planar and SPECT imaging. Amyloidosis Patient Registry  #Amyloidosis

With the advent and optimization of nuclear scintigraphy protocols using bone-avid radiotracers, cardiac amyloidosis caused by transthyretin protein (ATTR) can now be diagnosed noninvasively without a tissue biopsy. The radiotracer 99mTc-pyrophosphate (99mTc-PYP) binds to deposited ATTR amyloid fibrils in the myocardium and can be visualized using planar and SPECT imaging. This is Figure 2, showing how SPECT imaging allows the reader to distinguish between blood pool activity (ventricular cavity, etc) and myocardial activity and identify regional myocardial differences in radiotracer uptake.

News | Cardiac Diagnostics | March 05, 2020
March 5, 2020 — More than 300 patients have joined the Amyloidosis Patient Registry and it is now available to the en
heart disease image
News | Cardiac Diagnostics | December 18, 2019
December 18, 2019 — In their latest report, “...
FDA Warns Troponin Tests Impacted by Biotin Dietary Supplement
Feature | Cardiac Diagnostics | November 05, 2019 | Dave Fornell, Editor
November 5, 2019 — The U.S.
Videos | Cardiac Diagnostics | October 29, 2019
Doctor Clyde Yancy was a keynote speaker and said doctors need to check their assumptions about patients at the door...
79-year-old Tony Marovic had a right carotid endarterectomy shortly after discovering a 95 percent blockage of his carotid artery at a health and wellness screening event

79-year-old Tony Marovic had a right carotid endarterectomy shortly after discovering a 95 percent blockage of his carotid artery at a health and wellness screening event. Image courtesy of University Hospitals.

News | Cardiac Diagnostics | October 16, 2019
Health and wellness screenings are more than just nice events for the community – they can save lives. A Mentor, Ohio,...
Pesticide Exposure May Increase Heart Disease and Stroke Risk

Image courtesy of zefe wu from Pixabay

News | Cardiac Diagnostics | October 15, 2019
On-the-job exposure to high levels of pesticides raised the risk of heart disease and stroke in a generally healthy...
World Heart Federation Launches Global Roadmap on Cardiovascular Disease Prevention Among Diabetics
News | Cardiac Diagnostics | September 04, 2019
At the European Society of Cardiology (ESC) Congress 2019 together with the World Congress of Cardiology, the World...
Insomnia Tied to Higher Risk of Heart Disease and Stroke

Image courtesy of the American Heart Association

News | Cardiac Diagnostics | August 19, 2019
People suffering from insomnia may have an increased risk of coronary artery disease, heart failure and stroke,...