A new study released yesterday in the journal Nature Medicine determined that the fat and cholesterol in red meat isn’t what makes red meat a cardiovascular risk—but rather it’s the L-carnitine in red meat that’s troublesome.
Dr. Sinatra's Thoughts on the Red Meat Study
First off, I’ve been saying the same thing for years—that the cholesterol and fat in red meat aren’t the real cause of heart disease. But implicating the L-carnitine nutrient based on this type of research needs enormous future investigation and replication.
First off, this is a very complex study with a lot of moving parts. They looked at both mice and humans, giving mice a carnitine diet versus a non-carnitine diet. Then, they did the same thing with human meat eaters and compared them to vegan eaters. Then, based on the results, they implicated L-carnitine for contributing to cardiovascular disease—including plaque buildup in the blood vessels of the mice.
What happens in the gut is that your body metabolizes L-carnitine into a compound called Trimethylamine N-oxide (TMAO). People who regularly eat a lot of red meat have a lot of TMAO in their systems—and high levels of TMAO may lead to cardiovascular disease. Those who eat less red meat, on the other hand, have far fewer of the bacteria that turn L-carnitine into harmful TMAO—and therefore have better heart health.
The researchers suggested meat eaters could perhaps be given antibiotics to kill off the bacteria that turn L-carnitine into TMAO. I have another suggestion—cut back on red meat. And more importantly, cut back on red meat that’s treated with antibiotics, hormones, insecticides, pesticides and nitrites, as most of our meat supply is. I strongly suspect that it’s all of these chemicals in red meat that are causing the bacterial imbalance that’s leading to the build-up of harmful levels of TMAO.
Instead, Eat Red Meat that is Toxin-Free
I recommend eating range-fed buffalo, a red meat that contains none of the above environmental toxins. However, moderation is key when eating any range-fed meat. A 3.5 ounce serving every other day is reasonable. As I discussed in a 2012 newsletter article about cutting back on red meat to lower your heart health risk, over-consumption of red meat is associated with a higher incidence of both heart disease and cancer.
The researchers also suggested that, “the safety of chronic L-carnitine supplementation should be examined, as high amounts of orally ingested L-carnitine may under some conditions foster growth of gut microbiota with an enhanced capacity to produce TMAO and potentially advance atherosclerosis.” While this is a bold statement, obviously more research needs to be done when one considers the fact that there have been so many well-designed and replicated studies confirming the efficacy and safety of L-carnitine for human consumption.
When it comes to the use of L-carnitine as a supplement, a 500 mg ingested dose is only about 15% absorbed because the bioavailability of the compound is limited. So, a person taking a 500 mg dose is only getting about 75mg of L-carnitine, the equivalent found in a large serving (8-10 ounces) of red meat.
Should You Continue to Take Your L-Carnitine?
Absolutely! That is unless you’re chowing down on chemical-laden red meat daily (which I know doesn’t apply to any of you). It’s also important to remember that like CoQ10, your body manufactures L-Carnitine—and the reason it does is because it’s essential to good health. There are multiple animal studies that demonstrate the beneficial effects of supplemental L-carnitine in cardiovascular prevention. In addition, there are multiple human studies confirming the benefits of L-carnitine in documented heart disease, i.e. heart attack, angina, congestive heart failure, and atherosclerotic vessels.
The researchers raise the issue of TMAO concentrations, which does deserve further investigation. The connection between TMAO and antimicrobials may suggest a link between gut microflora and the theory that heart disease may have an infectious component, as well. The human GI tract has been extremely altered by the environmental toxins of this modern age. Chlorine is but one example. As the late Bernard Jensen often has been quoted: “Death and pathology begin in the colon.”
In conclusion, this study on red meat and L-carnitine raises a lot more questions than answers, but does not suggest more research into the role of our gut microflora and optimum health.
For now, I’m going to continue taking my L-carnitine (200 mg twice a day), and my acetyl L-carnitine (500 mg twice daily), as well as enjoy a modest serving (3-4 ounces) of free-range lamb, beef and bison, two or three times a week.
Now it's your turn: What are your thoughts on this study?