The Meat Risk of Heart Disease?
Yet another media controversy and medical debate is at full force (beyond the autism debate I discussed on my homepage at http://dr-lobisco.com/kids-vaccines-autism-risk/ ).
Recently, there has been much publication on the link between meat eaters and cardiovascular disease. Sounds fishy to me!
Why–we have another cholesterol controversy on our hands. This means that the good guy is getting blamed for a response in the body, not the other way around.
Heart Risk Tied to a Gut Bacteria’s Favorite, Meat-Derived Metabolite
The excerpt below explains the study that found a link between meat lovers and increased risk of heart disease. This was due to their gut bacteria burping up a nasty metabolite of an amino acid in protein, carnitine, and this in turn clogging their arteries:
It turns out that a compound that’s unusually abundant in red meat promotes atherosclerosis (hardening/clogging of the arteries).
The Cleveland Clinic group found that certain gut bacteria feed on an essential natural metabolic compound called carnitine … and break it down into a metabolite previously linked to atherosclerosis in people (Koeth R et al. 2013).
Further, the Cleveland researchers found that a diet high in carnitine – mostly obtained from red meat – promotes the growth of bacteria that metabolize carnitine into an artery-clogging compound. …
The researchers’ theory, based on earlier laboratory studies in animals, is twofold. First, TMAO facilitates the infiltration of oxidized cholesterol into artery walls … an essential part of the atherosclerosis process and cardiovascular disease.
And TMAO prevents the body from excreting excess cholesterol.
Weatherby, C. The Real Heart-Attacker in Red Meat? Vital Choice Newsletter. April 8, 2013
What the study fails to highlight, that in those deficient in carntitine, namely vegetarians, the link is not found, even after eating meat! This means the issue isn’t with the substance, it’s with the person’s digestive milieu.
Dietary Patterns not Meat contribute to Metabolite Breakdown
“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.”
Cleveland Clinic (CC). Cleveland Clinic researchers discover new link between heart disease and red meat. April 7, 2013. Accessed at http://www.eurekalert.org/pub_releases/2013-04/cc-ccr040513.php
Graham M, Crooke R, Edwards PA, Hazen SL, Lusis AJ. Trimethylamine-N-oxide, a metabolite associated with atherosclerosis, exhibits complex genetic and dietary regulation (abstract). Cell Metab. 2013 Jan 8;17(1):49-60. doi: 10.1016/j.cmet.2012.12.011.
Treat the Gut, Modulate Heart Disease Risk
Cure the Bacteria Burp and Liver yuck (emphasis mine):
Then researchers gave meat eaters doses of antibiotics to wipe out almost all of their gut bacteria. After that, they no longer had TMAO in their blood either after consuming red meat or carnitine pills. That meant, he said, that the effect really was because of gut bacteria.
Researchers then tried to determine whether people with high blood carnitine or TMAO levels were at higher heart disease risk. They analyzed blood from more than 2,500 people, asking if carnitine or TMAO levels predicted heart attacks independently of traditional risk factors like smoking, high cholesterol and blood pressure. Both carnitine and TMAO did. But upon further analysis, they discovered that the effect was solely because of TMAO.
The researchers’ theory, based on their laboratory studies, is that TMAO enables cholesterol to get into artery walls and also prevents the body from excreting excess cholesterol.
But what is it about carnitine that bacteria like? The answer, Dr. Hazen said, is that bacteria use it as a fuel.
He said he worries about carnitine-containing energy drinks. Carnitine often is added to the drinks on the assumption that is will speed fat metabolism and increase a person’s energy level, Dr. Hazen said.
Kolata, G. Study Points to New Culprit in Heart Disease. NY Times: Health. April 8, 2013. http://mobile.nytimes.com/2013/04/08/health/study-points-to-new-culprit-in-heart-disease.xml#.UWKhLybhJ_c.facebook
Bottom line:
Carnitine is needed for fuel for mitochondria (cellular energy), heart efficacy, and muscle strength, just to name a few functions.
So, don’t go tossing your supplements with carnitine out just yet. Consider your overall dietary patterns and check with a medical detective, i.e. functional medicine doctor or naturopathic Doctor, to determine your specific dietary needs.
