Carnitine, Coronary Heart Disease-Myocardial Ischemia and Diabetes
Carnitine is a naturally occurring extremely safe substance found in most human cells. It is, by far, the most widely researched cardiac nutraceutical regarding how it protects the heart against a lack of oxygen which occurs before a non-fatal or fatal heart attack. Doctors refer to this lack of oxygen as myocardial ischemia.
Here’s how it works. You all know about insulin. It transports sugar into the cells which then enters the cell’s furnaces or mitochondria to be metabolized in order to produce ATP or the energy molecule which keeps us alive. Carnitine, instead, transports fatty acids directly into the mitochondria to produce energy. Fatty acids, however, produce twice the amount of energy as sugars, and that’s why high energy requiring cells such as the heart and sperm tails almost exclusively use them for fuel or energy. Skeletal muscle also depends on fatty acids but to a lesser extent.
As I mentioned in previous posts, as a young doctor I wondered whether carnitine could protect the heart against myocardial ischemia both in its prevention and treatment. During the Vietnam War, I was stationed at WRAIR, the Walter Reed Army Institute of Research, where I met Major James Vick, an outstanding cardiovascular pharmacologist. He agreed with me on carnitine’s promise, and we then conducted a series of laboratory studies which showed that carnitine was highly effective in protecting the heart – both in the prevention and treatment of myocardial ischemia.
Though the results were, in a real sense, “spectacular” we couldn’t come up with a biochemical theory to explain the results. Then one day I got a call from Dr. Austin Shug, a well-respected scientist at the University of Wisconsin. He asked to meet with me along with his cardiologist colleague, James Thomsen. We met at O’Hare airport in Chicago. He discovered in laboratory studies that during ischemia, carnitine leaks out from the cardiac cells. When this happens the heart loses its ability to use fatty acids and switches to sugar instead. This is called anaerobic metabolism and is bad news for the patient. What follows are cardiac arrhythmias and often times fatal cardiac arrest. Carnitine is indeed nature’s way of protecting the heart against the lack of oxygen. They proposed a unique clinical study where the hearts of patients with coronary artery disease were electrically stimulated to work harder in order to determine whether intravenously administered carnitine would permit their hearts to pump longer and more forcefully before ischemic changes were seen. Carnitine did its job, and the results of the study were published in 1978 in the American Journal of Cardiology- a long time ago!
Since then a number of clinical studies have been published supporting carnitine’s natural anti-ischemic property. In a few studies, carnitine was given to patients immediately after a heart attack to determine whether it would preserve the thickness of the left ventricle, the part of the heart that pumps blood throughout the body. If the left ventricle is not preserved a patient can die from a heart attack or go into chronic congestive heart failure which is becoming common in our aging population. Carnitine impressively maintained the thickness of the ventricle. In a large study carnitine was given to patients with coronary heart disease and angina or chest pain where it reduced the number of angina attacks and also the amount of heart medication taken.
Over the years American physicians, including cardiologists, were unaware of carnitine’s cardiac properties let alone its existence. Recently, however, at “another” airport in Geneva, Switzerland, I met an American physician, David Kiefer, also like my aforementioned colleagues, from the University of Wisconsin, who informed me that many traditionally trained medical doctors are now routinely employing alternative medical treatments in their practices including carnitine for myocardial ischemia and chronic congestive heart failure. Needless to say, I was happy to hear the good news.
In a previous post I addressed the potential role of magnesium for the treatment of diabetes and the potential of carnitine to add to its benefit. There are a number of promising laboratory and clinical studies with respect to carnitine and diabetes. For example, it was found that lower carnitine blood levels were associated with an increase in diabetic complications. But, in my opinion, these studies are not convincing enough to persuade me to recommend carnitine supplementation. On the other hand, it certainly makes sense to administer carnitine together with it because of its anti-ischemic activity not only in the heart but in other tissues. Both types 1&2 diabetics have a more pervasive degree of total body ischemia then non-diabetic patients with large vessel atherosclerosis because, in addition, their very small arteries are also involved. As a previous diabetologist, if I were practicing today, I would not hesitate to prescribe both magnesium and carnitine. They are acceptably safe substances, and the risk-benefit ratio certainly favors the benefit. We are dealing with a classic Pascal’s Wager.