L-Carnitine is not an amino acid in the strict sense, but it bears similarity to amino acids and is usually grouped under that heading. It is also a vitamin-like nutrient related to the B vitamins. L-Carnitine is used by the body to transport long chain fatty acids to the mitochondria in your cells, where it is burned for energy. Since this fat burning is such a major source of muscular energy, deficiencies in carnitine are manifested as low energy levels and muscular weakness. They can also appear as mental confusion or cloudiness, angina (heart pain) and weight gain.
Carnitine can be manufactured in the body provided the necessary vitamins and minerals are present. These include vitamin B1, B6, C, and iron. The amino acids lysine and methionine are also needed. Carnitine is present in meat, particularly beef, sheep, and lamb. Other animal foods such as milk, cheese, and poultry contain somewhat less carnitine. The available research on L-carnitine supplementation does not appear to support claims of enhanced aerobic or anaerobic exercise performance.
Carnitine supplementation can help prevent fatty build-up in the heart and liver (especially likely if you are a regular consumer of alcoholic beverages).
L-Carnitine can help with the following
Alzheimer's Disease
In 19 male and 14 female subjects (mean ages 73.9 and 76.2 years, respectively) with Alzheimer’s disease who were non-responders to acetylcholinesterase inhibitor therapy, subjects were given in addition to their donepezil at 5mg/day or rivastigmine at 3mg, BID, acetyl-L-carnitine at 2gm/day, BID. There was an improvement in responders from 38% with drug therapy alone to 50% with the addition of acetyl-L-carnitine. [Curr Med Res Opin. 2003;19(4): pp.350-353]
Hyperthyroidism
In a double-blind, placebo-controlled trial, 50 women with normal thyroid function were given thyroid hormone and randomly assigned to three groups: placebo for six months; placebo for two months followed by 2gm or 4gm per day of L-carnitine for months three and four, then placebo for months five and six; or 2gm or 4gm per day of L-carnitine for the first four months followed by two months of placebo. Clinical symptoms such as palpitations and biochemical parameters worsened when patients took placebo, and returned to baseline or improved minimally during L-carnitine treatment. Bone loss is normally experienced during a hyperthyroid state, but bone mineral density improved throughout the trial in all patients taking L-carnitine. The authors suggest the supplement may be useful for both preventing and treating hyperthyroidism. [J Clin Endocrinol Metab 2001;86(8): pp.3579-94]
Angina
Several clinical trials have demonstrated that carnitine supplementation improves angina and heart disease. Improvements have been noted in exercise tolerance and heart function. In one study of patients with stable angina, oral administration of 900mg of L-carnitine increased mean exercise time and the time necessary for abnormalities to occur on a stress test.
These results indicate that carnitine may be an effective alternative to other anti-angina agents, especially in patients with chronic stable angina. [ Drugs Exp Clin Res 1991;17(4): pp.225-35, Eur Heart J 1996 Mar;17(3): pp.414-20]
Mitral Valve Prolapse
L-carnitine is an amino acid that acts as a shuttle for fat that is required for cellular metabolism and also acts to strengthen the heart. Dosage: 500-1,000mg two to three times daily. Acetyl-l-carnitine is a related nutrient that may be more bio-available. Dosage: 120mg three times daily.
Congestive Heart Failure
Carnitine seems to help people who have suffered congestive heart failure. [Drugs 34 1987: pp.1-24, Arzneim Forsch 42 1992: pp.1101-4]
Atherosclerosis
Dosage: 750 to 1,500mg bid. Important in fatty acid metabolism, depleted in cardiac muscle during acute infarctions.
Arrhythmias/Dysrhythmias
In a controlled trial, patients with exercise induced angina received L-carnitine at a dose of 2gm per day. After 6 months, compared to controls, they had a significant reduction in the number of premature ventricular contractions at rest and increased tolerance during exercise. Improvements were noticeable after 1 month and became more pronounced with continued treatment. [Drugs Exp Clin Res 17: pp.225-35, 1991]
Cardiomyopathy
There is a little evidence that carnitine may be useful in cardiomyopathy. [J Child Neurol (Canada) 10: pp.2S45-2S51, 1995] A deficiency of carnitine is associated with the development of some forms of cardiomyopathy. Inherited forms of cardiomyopathy seen in children may be the most responsive to therapy with L-carnitine. Will carnitine supplementation help the average person with cardiomyopathy? While it remains unknown, some doctors recommend up to 3gm of carnitine per day for the average adult. Carnitine is thought to work well with CoQ10, the two treatments being often combined.
Carnitine deficiency may also be implicated in diabetic cardiomyopathy [ J Diabetes Complications 1999 Mar-Apr;13(2):86-90.]
Chemotherapy Side-Effects/Risks
Treatment with L-carnitine for 7 days at 4gm per day ameliorated chemotherapy-induced fatigue until the next cycle of
chemotherapy in a study of 50 patients who received cisplatin or ifosfamide. [Br J Cancer 2002;86(12): pp.1854-1857]
Neuritis/Neuropathy
L-Acetyl Carnitine (LAC) was effective and well tolerated in improving neurophysiological parameters and in reducing pain over a 1-year period. LAC is, therefore, a promising treatment option in patients with diabetic neuropathy. [Drugs R D. 2002;3(4):223-33]
Another study conducted in a British Hospital found that LAC can greatly reduce the damage caused to nerves by certain HIV drugs, even promoting nerve regeneration. [AIDS 2004;18: 1549-1560, 2004] The dose in this study was 3 grams per day (1500mg bid).
Diabetes Type II
The amino acid L-carnitine improves insulin sensitivity in type 2 diabetes.
Increased Risk of Liver Cancer
The study was published on March 21, 2009 in World Journal of Gastroenterology. A research group in King Saud University, Kingdom of Saudi Arabia investigated, for the first time, the role of carnitine, a naturally occurring compound that is synthesized mainly in the liver, during the development of hepatocarcinogenesis. Authors of the study reported that carnitine deficiency is a risk factor and should be viewed as a mechanism in hepatic carcinogenesis, and that long-term L-carnitine supplementation prevents the development of liver cancer. Therefore, carnitine supplementation alone or in combination with other natural chemopreventive compounds could be used to prevent, slow or reverse the occurrence of liver cancer.
Liver Cancer
The study was published on March 21, 2009 in World Journal of Gastroenterology. A research group in King Saud University, Kingdom of Saudi Arabia investigated, for the first time, the role of carnitine, a naturally occurring compound that is synthesized mainly in the liver, during the development of hepatocarcinogenesis. Authors of the study reported that carnitine deficiency is a risk factor and should be viewed as a mechanism in hepatic carcinogenesis, and that long-term L-carnitine supplementation prevents the development of liver cancer. Therefore, carnitine supplementation alone or in combination with other natural chemopreventive compounds could be used to prevent, slow or reverse the occurrence of liver cancer.
Key
| May do some good |
| Likely to help |
| Highly recommended |
Glossary
Amino Acid
An organic acid containing nitrogen chemical building blocks that aid in the production of protein in the body. Eight of the twenty-two known amino acids are considered "essential," and must be obtained from dietary sources because the body can not synthesize them.
Fatty Acids
Chemical chains of carbon, hydrogen, and oxygen atoms that are part of a fat (lipid) and are the major component of triglycerides. Depending on the number and arrangement of these atoms, fatty acids are classified as either saturated, polyunsaturated, or monounsaturated. They are nutritional substances found in nature which include cholesterol, prostaglandins, and stearic, palmitic, linoleic, linolenic, eicosapentanoic (EPA), and decohexanoic acids. Important nutritional lipids include lecithin, choline, gamma-linoleic acid, and inositol.
Mitochondrion
Structure inside a cell that is the location of the cell's energy production machinery. (Plural: Mitochondria)
Carnitine
A compound found in skeletal and cardiac muscle and certain other tissues that functions as a carrier of fatty acids across the membranes of the mitochondria. Carnitine has been used therapeutically in treating angina and certain deficiency diseases.
Angina
Angina pectoris. Severe, restricting chest pain with sensations of suffocation caused by temporary reduction of oxygen to the heart muscle through narrowed diseased coronary arteries.
Mineral
Plays a vital role in regulating many body functions. They act as catalysts in nerve response, muscle contraction and the metabolism of nutrients in foods. They regulate electrolyte balance and hormonal production, and they strengthen skeletal structures.
Thiamine
(Vitamin B-1): A B-complex vitamin that acts as a coenzyme necessary for the conversion of carbohydrates into glucose, which is burned in the body for energy. It is essential for the functioning of the nervous system.
Vitamin B6
Influences many body functions including regulating blood glucose levels, manufacturing hemoglobin and aiding the utilization of protein, carbohydrates and fats. It also aids in the function of the nervous system.
Iron
An essential mineral. Prevents anemia: as a constituent of hemoglobin, transports oxygen throughout the body. Virtually all of the oxygen used by cells in the life process are brought to the cells by the hemoglobin of red blood cells. Iron is a small but most vital, component of the hemoglobin in 20,000 billion red blood cells, of which 115 million are formed every minute. Heme iron (from meat) is absorbed 10 times more readily than the ferrous or ferric form.
Lysine
Essential amino acid. Important for growth, tissue repair, and the production of hormones, enzymes and antibodies. Research indicates that lysine may be useful in the treatment of migraine and herpes simplex. Precursor to carnitine in the body.
Methionine
Essential amino acid. Dietary source of sulfur and methyl groups. Important for proper growth in infants, nitrogen balance in adults, healthy nails and skin and the synthesis of taurine, cysteine, phosphatidylcholine (lecithin), bile, carnitine and endorphins. It is an antioxidant nutrient and lipotropic agent which promotes the physiological utilization of fat.
Aerobic
Using oxygen. For example, aerobic exercises such as running, swimming, bicycling or playing tennis use up lots of oxygen and burn up lots of calories and fat.
Anaerobic
Of, relating to, or being activity in which the body incurs an oxygen debt (for example weight training or resistive exercises) and does not immediately burn off a lot of calories and fat.