By David Blyweiss, M.D., Advanced Natural Wellness
May 6, 2013
- Why mice shouldn’t take carnitine supplements
- How this amino acid protects your heart and extends your life
- The best way to keep meat in your diet
For years there has been a perception that the saturated fat and cholesterol found in red meat was the leading culprit in heart disease. But there has never been any strong evidence to back up this assertion.
And these days health experts are finally admitting meat isn’t the big killer they previously said it was. It never has been.
But just when we’ve come to our senses, a new study is demonizing red meat all over again.
The news hounds have been all over the story. And they’ve blown it way out of proportion.
The study was released from researchers at the Cleveland Clinic on April 7th.
In it, the authors suggest carnitine, found in red meat, might set off a chain of events that increases the risk of heart disease.
Apparently, certain stomach bacteria feed on the carnitine that enters your digestive tract after eating red meat. Then the bacteria burp out a chemical which increases levels of trimethylamine-N-oxide (TMAO) in the bloodstream.
The researchers believe it’s this increased level of TMAO that leads to hardening of the arteries.
To test things out, they fed mice a carnitine supplement. Sure enough, “chronic” supplementation with carnitine increased the risk of atherosclerosis in mice. And the researchers believed elevated TMAO was the reason.
Of course, if we were mice we would never intentionally take a carnitine supplement. So you have to wonder how this translates to people.
Well, when five meat-eaters and one vegan ate steak, the meat-eaters had increased TMAO levels. However, the vegan didn’t.
When carnitine supplements were given to five meat-eaters and five vegetarians or vegans, the results were similar. TMAO increased in the meat-eaters, but not the others.
Now this doesn’t say eating meat or taking carnitine increased the omnivore’s risk of heart disease or atherosclerosis. That link has NOT been firmly established.
It simply says it increased TMAO levels in people who eat meat, but not those who don’t.
What does this mean for you? Is this enough evidence to say you shouldn’t be eating meat?
Just days after the study above was released, the Mayo Clinic released a truly newsworthy analysis. And you know what? It didn’t receive nearly the same amount of media coverage.
I guess it’s because it wasn’t scary enough. Quite the opposite. This study was loaded with good news about carnitine.
The research involved 13 studies and 3,629 patients. And it revealed the numerous heart benefits associated with carnitine, including…
- 40% reduction in angina symptoms in patients experiencing a heart attack
- 65% reduction in ventricular arrhythmias
- 27% reduction in all-cause mortality
But that’s not all.
What about the massive meta-analysis released just a couple years ago? You probably don’t remember reading about it. But it was big news at the time.
This huge analysis included 20 different studies. And more than 1.2 million people were involved.
The researchers wanted to find out if there was a relationship between certain types of meat and the risk of heart disease, stroke and diabetes. They included red, processed and total meat consumption in their analysis.
Guess what they discovered?
- There was NO association between red meat and heart disease.
- Red meat was NOT associated with an increased risk of diabetes.
- Red meat DID NOT increase stroke risk.
Now these results don’t hold true for processed meat, so that’s something to note.
But additional research shows that, among other things, carnitine also improves endothelial function, blood pressure, insulin resistance and blood glucose.
I’m not saying you should be digging into a steak for lunch, breakfast and dinner every day. But there is a very healthy and satisfying way to get your fill of red meat…
I’ve given considerable thought to exactly why meat eaters produce more TMAO than vegetarians. And I think one thing is very clear.
The intestinal bacteria in people who eat meat must differ considerably from that found in vegetarians.
Just think about it.
After a person who eats meat regularly consumes meat or carnitine, TMAO levels are increased. And a certain type of gut bacteria is directly linked to that increase. But this same reaction doesn’t occur in vegetarians.
This, in itself, may explain things. That’s because fruits and vegetables have a positive effect on the growth of certain bacteria in your digestive tract.
However, there are plenty of people who don’t consume their fare share of fresh veggies and fruits every day. And meat-eaters may fall into that group.
That’s why I think switching to a modified Mediterranean diet is one of the best things anyone – and everyone – should do.
The Mediterranean style of eating is one of the most healthful on the planet. It allows you to enjoy red meat while offering a full range of fresh foods loaded with antioxidants, phytonutrients and omega-3 fatty acids.
And here’s the icing on the cake…
Researchers recently compared the heart benefits of a low-fat diet against a Mediterranean diet.
The low-fat group was allowed to have one or less servings of red meat each week. However, the folks in the Mediterranean group could have less than a full serving of red meat every day.
Guess which produced the best health results?
Even allowing for more meat consumption, the Mediterranean way of eating prevented heart disease much better than the low-fat diet.
You can learn all about my modified Mediterranean diet here.
In the meantime, the only caveat I have is this. Make sure you select fresh (not processed) red meats from grass-fed cattle.
Koeth RA, et al. Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med. 2013 Apr 7. [Epub ahead of print]
James J. DiNicolantonio, et al. L-Carnitine in the Secondary Prevention of Cardiovascular Disease: Systematic Review and Meta-analysis. Mayo Clinic Proceedings – 17 April 2013 (10.1016/j.mayocp.2013.02.007)
Renata Micha, et al. Red and processed meat consumption and risk of incident coronary heart disease, stroke, and diabetes: A systematic review and meta-analysis. Circulation. 2010 June 1; 121(21): 2271–2283.
Ruggenenti P, et al. Ameliorating hypertension and insulin resistance in subjects at increased cardiovascular risk: effects of acetyl-L-carnitine therapy. Hypertension. 2009 Sep;54(3):567-74.
De Marchi S, et al. Propionyl-L-carnitine improves endothelial function, microcirculation and pain management in critical limb ischemia. Cardiovasc Drugs Ther. 2012 Oct;26(5):401-8.
Li F, et al. Human gut bacterial communities are altered by addition of cruciferous vegetables to a controlled fruit- and vegetable-free diet. J Nutr. 2009 Sep;139(9):1685-91. Epub 2009 Jul 29.
Estruch R, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med. 2013 Apr 4;368(14):1279-90. Epub 2013 Feb 25