Description of carnitine

The body synthesises the carnitine it needs from lysine and methionine, two amino acids found in food.

This process also requires the presence of vitamin C, iron, vitamin B6 and vitamin B3 (niacin) and various enzymes.

Carnitine plays an essential role in the transport of long chain fatty acids within the mitochondria (components of the body's cells).

This process in the mitochondria enables the production of energy in the form of adenosine triphosphate (ATP).

Carnitine is therefore essential for the proper functioning of muscles, including the heart, a muscle that is constantly being used and therefore constantly needs 'fuel'.

In the body, carnitine is mainly synthesised by the liver and kidneys.

Commercially, it is synthesised in a laboratory and sold as a dietary supplement in the form of L-carnitine and acetyl L-carnitine (in capsules, tablets, powder to be diluted, etc.).

L-carnitine is water soluble, whereas acetyl L-carnitine is fat soluble.

Indications

Uncertain effectiveness

Improvement of physical performance.

Medical use

Carnitine is being used experimentally as an adjuvant in the treatment of angina pectoris, heart failure, cardiomyopathy and the sequelae of myocardial infarction.

Trials have also been carried out in people with Alzheimer's disease and diabetic neuropathy.

Dosage 

Current data suggests that a dose of 2g of L-carnitine per day, divided into 1 to 3 doses, does not appear to present any health risks.

Food sources

The body synthesises the carnitine it needs from food.

The best sources are meat, especially red meat, and to a lesser extent dairy products, avocados and tempeh (a fermented soy product).

The dietary intake of carnitine in modern societies is estimated to be between 20mg and 200mg per day, which is much lower than the doses used in clinical trials.

However, dietary carnitine is much better absorbed (75%) than supplemental carnitine (5% to 18%).

Carnitine deficiency

Carnitine deficiency is relatively uncommon.

It can be caused by the use of certain drugs (e.g. valproic acid, antiepileptic drugs and reverse transcriptase inhibitors such as AZT) or prolonged dialysis treatment.

It can also be caused by certain genetic disorders or a metabolic disorder that interferes with the normal synthesis of this substance in the body.

Premature babies who are intubated are at risk of carnitine deficiency. This can lead to muscle weakness, increased fatigue and cardiac arrhythmias.

Interactions

With herbs or supplements: None known.

With medicines: Carnitine has been reported to increase the effects of acenocoumarol (Sintrom®), an anticoagulant that works for a shorter time than warfarin. It is not known whether carnitine enhances the effects of warfarin.