Heart disease and the chemical TMAO connection - Part 1

Heart disease and the chemical TMAO connection – Part 1

Just when we thought all the early death and disease caused by meat was from saturated fat, toxic chemicals, hormones, unnecessary cholesterol, a lack of fibre causing constipation and more… another mechanism is uncovered.

“The investigative and extensive experiments in both humans and animals have persuaded scientists not connected with the study to seriously consider this new theory of why red meat eaten too often might be bad for people…the often-noticed association between red meat consumption and heart disease risk might be related to more than just the saturated fat and cholesterol in red meats like beef and pork”
New York Times, April 7, 2013.

Cardiovascular disease is a complex multifactorial process – this is one facet of the story – a new facet – one not yet known before.  We did not expect to see such a dramatic difference [between plant-eaters and meat-eaters].  The bacteria living in our digestive tracts are dictated by our long-term dietary patterns.  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.  Carnitine metabolism suggests a new way to help explain why a diet rich in red meat promotes atherosclerosis (narrowing of the arteries).  Meanwhile, vegans and vegetarians have a significantly reduced capacity to synthesize TMAO from carnitine, which may explain the cardiovascular health benefits of these diets.  TMAO may be a waste product but it is significantly influencing cholesterol metabolism and the net effect leads to an accumulation of cholesterol.  Cholesterol is still needed to clog the arteries but TMAO changes how cholesterol is metabolized, like the dimmer on a light switch.  It may explain why two people can have the same LDL level [a measure of one type of cholesterol], but one develops cardiovascular disease and the other doesn’t.  Cholesterol, saturated fat and salt only account for a tiny little piece of the risk.  Chronic exposure to dietary carnitine, whether from food or supplement, may not be a healthy thing for the vasculature over the long run.  High blood levels of TMAO are an astoundingly good warning sign of impending heart attack, stroke and death.  The findings support the idea that less red meat is better
Dr Stanley Hazen, Ph.D., Chairman of the department of cellular and molecular medicine, Vice Chair of Translational Research for the Lerner Research Institute, and section head of Preventive Cardiology and Rehabilitation in the Miller Family Heart and Vascular Institute at Cleveland Clinic.

"It’s really a beautiful combination of studies to tell a story I find quite plausible”
Dr. Daniel J. Rader, heart disease researcher, University of Pennsylvania School of Medicine.

“The notion that there’s something more to red meat than just saturated fats has been banging around for a long while.  This is the first scientific link that may explain at least part of that association.  This is a very interesting and provocative study, and just peels back the onion a little bit on this very complex question of coronary heart disease”
Stuart Seides chief of the MedStar Heart Institute, Washington. 

“I don’t have any reason to doubt it…it is kind of amazing”
Dr. Frank Sacks, professor of cardiovascular disease prevention, Harvard School of Public Health.

Lora Hooper, an associate professor of immunology and microbiology at the University of Texas Southwestern Medical Center, who follows the Paleo meat-heavy diet.

Posted: Thursday 13 February 2014