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What the Heck is L-Carnitine?

Fitday Editor

L-Carnitine is derived from an amino acid that is found in almost all of the cells in the body. Carnitine is a generic term for several compounds known as acetyl-L-carnitine, L-carnitine and propionyl-L-carnitine. Carnitine plays an important role in energy production in the mitochondria of the cells and transports toxic compounds out of the cells to prevent them from accumulating in the body. The body makes carnitine from the amino acids lysine and methionine to meet our daily needs.

Where Do You Get L-Carnitine?

You can find carnitine in food sources including chicken, fish, meat and milk. Those who eat red meat and other animal products receive about 60 to 180 milligrams of carnitine per day. Vegans receive considerably less, only about 10 to 12 milligrams per day since they avoid animal-source food products. Over 50 percent of dietary carnitine is absorbed in the small intestine and then enters the bloodstream. Most people obtain sufficient carnitine naturally through a diet that includes:

• A variety of fresh fruits, vegetables, whole-grains and fat-free, low-fat dairy products
• Lean meats, eggs, fish, chicken and nuts
• Low saturated fats, trans fats and cholesterol, salt and added sugars
• Appropriate daily caloric needs

L-Carnitine Deficiencies

A deficiency can occur if one has kidney problems, renal failure, skeletal-muscle weakness, hypoglycemia or cardiomyopathy. Carnitine has been studied extensively due to its ability to help with energy production, weight loss and improve athletic performance. However, over twenty years of research finds no consistent evidence that carnitine supplements can improve exercise or physical performance in healthy people. However, there is evidence to show a carnitine supplement can help in certain situations.

L-Carnitine and Aging

Mitochondria are like tiny, little packages inside each of our cells. A decline in their function can contribute to the aging process. Supplementing with carnitine has been shown to reduce mitochondrial decay when taken with alpha-lipoic acid (an antioxidant). It has also been shown to improve memory, mental function and reduce deterioration in older adults with mild cognitive impairment and Alzheimer's disease.

L-Carnitine and Cardiovascular Disease

Several studies have shown supplementing with carnitine can help manage cardio ischemia (restriction of blood flow to the heart) and peripheral arterial disease that includes poor circulation in the legs. Levels of carnitine are low in the heart muscle when dealing with these health issues so supplementing with carnitine has been beneficial to the heart muscle.

L-Carnitine and Cancer

Chemotherapy, radiation treatment and poor nutrition is common in cancer patients. Some studies show that when patients supplemented with carnitine they experienced less fatigue, improved mood and better quality of sleep.

L-Carnitine and Type-2 Diabetes

Insulin resistance can lead to Type-2 Diabetes and early research has shown that supplementing with L-carnitine intravenously improves insulin sensitivity. It helped diabetics by decreasing fat levels in the muscle and may lower glucose levels in the blood. An added benefit is the reduction of nerve pain and improved vibration perception in those dealing with diabetic neuropathy.

L-Carnitine and HIV

Those dealing with HIV often accumulate fat in some areas of the body and lose fat in others developing high levels of blood fats and insulin resistance. This can lead to a carnitine deficiency, so supplementing with carnitine both intravenously and orally can reduce neuropathy and affect blood lipid levels in a positive way.

Losing Weight with L-Carnitine

According to the University of Pittsburgh Medical Center, Acetyl L-Carnitine could help you lose weight by improving your fat-to-muscle ratio, or body composition and reduce fatigue. Althought acetyl L-carnitine is sometimes marketed as a weight loss or sports performance enhancing supplement, there is no conclusive medical research that supports it fully for weight loss. It may also be unsafe for people with low-thyroid hormone levels, people undergoing dialysis, pregnant or breastfeeding women and those with kidney or liver disease. Talk with your doctor before taking carnitine if you have high blood pressure, liver cirrhosis, diabetes or peripheral vascular disease. Carnitine supplements can interfere with thyroid medications as well.

Sherry L. Granader is a Sports Nutritionist, National Speaker and Spokesperson, Author of 2 healthy cookbooks, Writer, Ghost Writer, Nationally Certified Fitness Instructor and Personal Trainer. She has shared the stage with such celebrities as Whoopi Goldberg, Suze Orman and the late Governor Ann Richards and served as the On-Air Nutritionist for QVC television in the United States and the UK. She has cooked for her favorite bodybuilder, Lou Ferrigno (The Incredible Hulk) and his family, shared her nutrition expertise with Chuck Norris on the set of his movie "Sidekicks" and appeared on 8-time Mr. Olympia, Lee Haney's Championship Workouts on ESPN. Sherry hosted her own "Healthy Living" show on PBS for several years. For more information on Sherry, visit or write to Sherry at [email protected].

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