Preliminary Study Questions Carnitine’s Role in Cardiovascular Disease, Generates Misleading Media Headlines
A recent investigational study published by Koeth et al. in the journal Nature Medicine1 examined levels of a compound called trimethylamine-N-oxide (TMAO) in relationship to microbial metabolism of carnitine in the gut. The researchers cite very recent, limited research suggesting TMAO may be a risk factor for cardiovascular disease. They then provocatively propose that carnitine consumption may increase cardiovascular risk in some individuals due to increasing TMAO levels following microbial metabolism of the compound.
The authors report the intestinal bacterial flora of people who consume red meat, a source of dietary carnitine, was conducive to TMAO production in the presence of carnitine, whereas vegetarians produced little to no TMAO under the same circumstances. They concluded that alterations in the intestinal microbiota associated with meat consumption may promote the formation of TMAO from dietary carnitine, and therefore suggested that the carnitine content of red meat may be one of the reasons it is linked to heart disease.
Following publication of this study, mainstream media outlets propagated misleading headlines blaming carnitine for heart disease without explaining that these findings were very preliminary and that red meat consumption was required for the observed effect. Life Extension® members are well aware of the potential health threats associated with red meat consumption, such as exposure to saturated fats and advanced glycation end products,4 and many already consume a heart-healthy, plant-based diet such as the Mediterranean diet.
These deceptive media headlines have generated concern that supplemental forms of L-carnitine may be detrimental to heart health. This notion flies in the face of numerous published, peer-reviewed studies showing L-carnitine promotescardiovascular health in a variety of ways. The media’s effort to generate headlines has undermined decades of scientific research on the heart-health benefits of carnitine.
New Mayo Clinic Meta-Analysis: Carnitine Improves Outcomes in Heart Attack Patients
Ironically, days after publication of the Koethe et al. carnitine article, a new meta-analysis of the research on carnitine and heart health was published by researchers from Mayo Clinic. This large systematic review provides strong evidence for carnitine’s benefits in heart health. This article examined 13 controlled trials that enrolled, collectively, 3629 participants, representing the largest, most powerful scientific review of carnitine’s cardiovascular benefits to date.2
The authors of the Mayo Clinic study found carnitine supplementation was associated with a 27% reduction in all-cause mortality, a 65% reduction in ventricular arrhythmias, and a 40% reduction in angina symptoms in patients who had experienced a heart attack. These effects were thought to occur through multiple mechanisms, including improved energy metabolism in the mitochondria, decreased ischemia, and enhanced left ventricle function.2
The authors describe carnitine as an inexpensive therapy with an “excellent safety profile” which could potentially be used in patients with angina or who are at risk for angina after suffering from a heart attack. Based on the results of this meta-analysis, the authors suggest L-carnitine as a potential future therapy for heart attack and secondary coronary prevention and treatment, including angina. The scientists state: “Further study with large randomized controlled trials of this inexpensive and safe therapy in the modern era is warranted.” Unfortunately they also note:”However, a large trial may never be performed because L-carnitine is an over-the-counter supplement available to the public, which decreases the potential revenue compared with a synthesized [pharmaceutical] product.”2
Carnitine’s benefits are well-established and Life Extension® has written about them at length over the years. The next several paragraphs describe some of the key health benefits associated with carnitine.
Misleading is right and it’s important to realize that red-meat is often a risk factor for those who consume it too much, which does NOT apply to everyone.
See on www.lef.org