Can the Amino Acid L-Carnitine Be Linked to Cardiac Health? (May 2014)
I see clients who bring their medicine cabinet in of supplements in review. Individuals either begin taking supplements as the internet/magazine has suggested as a good idea or to take these supplements after their internist’s recommendations. If you are taking supplement (s) this article will discuss the latest findings on the amino acid called L-carnitine.
The latest research indicates that by maintaining adequate levels of this amino acid then perhaps this will improve the health of the cardiac patient. Carnitine is found naturally in red meat and synthetically as an over the counter supplement. L-carnitine plays a significant role in blood glucose regulation, energy metabolism, in muscle tissue and in the heart’s myocardium. L-carnitine also helps transport long chain fatty acids across the mitochondrial membrane where they become a main factor in energy production which is then metabolized through beta-oxidation.
In the heart, L-carnitine becomes especially important as the myocardium prefers to oxidize long-chain fatty acids for energy. It also removes toxins, inhibits fatty acid accumulation during ischemic events, and prevents cardiac cell death.
Since L-carnitine is important in metabolic pathways, it is touted as a supplement to increase energy, promote weight loss as well as improve athletic performance. These claims have not been supported by clinical research studies. When L-carnitine is used as an ergogenic aid (sports performance enhancer) the research has been disappointing. The research shows that plasma levels increase with supplementation, the intramuscular concentration of L-carnitine doesn’t always increase, and performance isn’t consistently affected.
According to Janet Bond Brill, PhD, RD, LDN, author of Blood Pressure Down! L-carnitine is synthesized in the body from the amino acids lysine and methionine. As a result we don’t need to eat or take it in a supplement form. The average person gets adequate amounts of this amino acid in their diet alone.
Current Research is now reviewing whether the effects of L-carnitine supplementation are promising for the cardiac patient. The latest research shows that having adequate levels of this amino acid in the heart muscle can be beneficial to offer several protective benefits but the verdict is still out if it can effectively treat cardiac disease. Before taking any supplement on your own, I would always consult with your cardiologist or your primary care physician.
A meta-analysis review was done in the June issue of Mayo Clinic Proceedings which shows how a team of researchers evaluates L-carnitine on heart health. The research was done over the last 30 years evaluating 13 clinical trials including more than 3,600 cardiac patients all whom had a history of an acute MI (Myocardial Infarction). The researchers concluded that L-carnitine was safe, cost effective for cardiac patients and reduced mortality from all causes (27%), a decline in ventricular arrhythmias (65%), and a decrease in angina(40%). The research failed to show any correlation between supplemental L-carnitine and reoccurrence of an MI or heart failure.
The researchers also mentioned that this study was not conducted in an aggressive manner. This means that dietary changes were taken into consideration as well as different medications that were used than may have been recommended. It was recommended that further research be done for acute coronary syndrome than the dosage that was used.
It is speculated that the minimum dosage for the 13 trials of L-carnitine was 2 gm day, but the optimal amount is 6-9 gm/day. The exact dosage recommendation remains unclear.
With all of this positive news noted above there is also some conflicting evidence too. Although some people may have positive results with L-carnitine supplementation, it is important to note that a high dietary intake of L-carnitine has been linked with an increased risk of heart disease.
Red meat has been the food that elevated L-carnitine levels. According to Janet Bond Brill, PhD, RD, LDN “L-carnitine is metabolized by the intestinal microbiotia to trimethylamine-N-oxide, an atherogenic substance which increases risk of cardiovascular disease”.
Since this information is all new I would recommend obtaining your L-carnitine via supplementation vs. the dietary choices that I mentioned above. By having a diet that is high in red meat to obtain your L-carnitine research shows that it is not recommended for a variety of reasons.
References:
1. Janet Bond Brill, Ph.D, RD, LDN, Blood Pressure Down! (2013)
2. Oyanagi E, Yano H, Uchida M, Utsumi K, Sasaki J. Protective action of L-carnitine on mitochondrial function and structure against fatty acid stress. Biochemical & Biophysical
3. 3. McArdle WD, Katch Fl, Katch Vl. Sports and Exercise Nutrition, 4th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2012.
4. 4. Koeth RA, Wang Z, Levison BS, et al. Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis, Natural Medicine Journal. 2013;19(5) 576-585.
