Navigation Links
Cleveland Clinic researchers discover new link between heart disease and red meat

EMBARGOED UNTIL 1 P.M. EDT, APRIL 7, 2013, Cleveland: A compound abundant in red meat and added as a supplement to popular energy drinks has been found to promote atherosclerosis or the hardening or clogging of the arteries according to Cleveland Clinic research published online this week in the journal Nature Medicine.

The study shows that bacteria living in the human digestive tract metabolize the compound carnitine, turning it into trimethylamine-N-oxide (TMAO), a metabolite the researchers previously linked in a 2011 study to the promotion of atherosclerosis in humans. Further, the research finds that a diet high in carnitine promotes the growth of the bacteria that metabolize carnitine, compounding the problem by producing even more of the artery-clogging TMAO.

The research team was led by Stanley Hazen, M.D., Ph.D., Vice Chair of Translational Research for the Lerner Research Institute and section head of Preventive Cardiology & Rehabilitation in the Miller Family Heart and Vascular Institute at Cleveland Clinic, and Robert Koeth, a medical student at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University.

The study tested the carnitine and TMAO levels of omnivores, vegans and vegetarians, and examined the clinical data of 2,595 patients undergoing elective cardiac evaluations. They also examined the cardiac effects of a carnitine-enhanced diet in normal mice compared to mice with suppressed levels of gut microbes, and discovered that TMAO alters cholesterol metabolism at multiple levels, explaining how it enhances atherosclerosis.

The researchers found that increased carnitine levels in patients predicted increased risks for cardiovascular disease and major cardiac events like heart attack, stroke and death, but only in subjects with concurrently high TMAO levels. Additionally, they found specific gut microbe types in subjects associated with both plasma TMAO levels and dietary patterns, and that baseline TMAO levels were significantly lower among vegans and vegetarians than omnivores. Remarkably, vegans and vegetarians, even after consuming a large amount of carnitine, did not produce significant levels of the microbe product TMAO, whereas omnivores consuming the same amount of carnitine did.

"The bacteria living in our digestive tracts are dictated by our long-term dietary patterns," Hazen said. "A diet high in carnitine actually shifts our gut microbe composition to those that like carnitine, making meat eaters even more susceptible to forming TMAO and its artery-clogging effects. Meanwhile, vegans and vegetarians have a significantly reduced capacity to synthesize TMAO from carnitine, which may explain the cardiovascular health benefits of these diets."

Prior research has shown that a diet with frequent red meat consumption is associated with increased cardiovascular disease risk, but that the cholesterol and saturated fat content in red meat does not appear to be enough to explain the increased cardiovascular risks. This discrepancy has been attributed to genetic differences, a high salt diet that is often associated with red meat consumption, and even possibly the cooking process, among other explanations. But Hazen says this new research suggests a new connection between red meat and cardiovascular disease.

"This process is different in everyone, depending on the gut microbe metabolism of the individual," he says. "Carnitine metabolism suggests a new way to help explain why a diet rich in red meat promotes atherosclerosis."

While carnitine is naturally occurring in red meats, including beef, venison, lamb, mutton, duck, and pork, it's also a dietary supplement available in pill form and a common ingredient in energy drinks. With this new research in mind, Hazen cautions that more research needs to be done to examine the safety of chronic carnitine supplementation.

"Carnitine is not an essential nutrient; our body naturally produces all we need," he says. "We need to examine the safety of chronically consuming carnitine supplements as we've shown that, under some conditions, it can foster the growth of bacteria that produce TMAO and potentially clog arteries."

This study is the latest in a line of research by Hazen and his colleagues exploring how gut microbes can contribute to atherosclerosis, uncovering new and unexpected pathways involved in heart disease. In a 2011 Nature study, they first discovered that people are not predisposed to cardiovascular disease solely because of their genetic make-up, but also based on how the micro-organisms in their digestive tracts metabolize lecithin, a compound with a structure similar to carnitine.


Contact: Laura Ambro
Cleveland Clinic

Related biology news :

1. Cleveland Clinic research shows anemia drug does not improve health of anemic heart failure patients
2. Cleveland Clinic develops clinical screening program for no.1 genetic cause of colon cancer
3. Cleveland Clinic researchers receive $5 million grant to discover novel pathways to heart disease
4. NYSCF scientists develop new protocol to ready induced pluripotent stem cell clinical application
5. ACMG releases report on incidental findings in clinical exome and genome sequencing
6. IUPUI stem cell research could expand clinical use of regenerative human cells
7. New AAN/ALS Association Clinical Fellow Will Pursue Immune Biomarkers
8. Sanford-Burnham Medical Research Institute and Mayo Clinic extend collaborative agreement
9. Preclinical study shows potential of new technologies to detect response to cancer therapy earlier
10. Major clinical trial finds no link between genetic risk factors and 2 top wet AMD treatments
11. Acquisition of BioClinica, Inc. by JLL Partners, Inc. May Not Be in BioClinica, Inc. Shareholders Best Interests
Post Your Comments:
(Date:11/18/2015)... -- As new scientific discoveries deepen our understanding of how ... face challenges in better using that knowledge to guide ... more children continue to survive pediatric cancer, that counseling ... John M. Maris, M.D ., a pediatric ... . --> John M. Maris, M.D ...
(Date:11/17/2015)... PARIS , November 17, 2015 ... November 2015.   --> Paris from ... --> DERMALOG, the biometrics innovation leader, has invented the ... and fingerprints on the same scanning surface. Until now two ... fingerprints. Now one scanner can capture both on the same ...
(Date:11/17/2015)... LIVERMORE, Calif. , Nov. 17, 2015  Vigilant ... has joined its Board of Directors. ... Vigilant,s Board after recently retiring from the partnership at ... owning 107 companies with over $140 Billion in revenue.  ... performance improvement across all the TPG companies, from 1997 ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... SHPG ) announced today that Jeff Poulton , Chief ... Annual Healthcare Conference in New York City , ... p.m. GMT). --> SHPG ) announced today that ... Jaffray 27 th Annual Healthcare Conference in New ... 8:30 a.m. EST (1:30 p.m. GMT). --> Shire plc ...
(Date:11/24/2015)... ... 2015 , ... In harsh industrial processes, the safety of ... can represent a weak spot where leaking process media is a possible hazard. ... , which are designed to tolerate extreme process conditions. They combine rugged design ...
(Date:11/24/2015)... CHARLOTTESVILLE, Va. , Nov. 24, 2015 /PRNewswire/ ... company focused on discovering drugs for metabolic disorders, ... Watkins to its Board of Directors (BOD). ... executive officer of Human Genome Sciences (HGS), and ... Industry Organization. Jim Powers , Chairman ...
(Date:11/23/2015)... 24, 2015 Women with a certain type of ... a higher risk of lung cancer than men with similar ... at the annual meeting of the Radiological Society of ... --> --> Lung nodules are small masses ... or subsolid based on their appearance on CT. Solid nodules ...
Breaking Biology Technology: