Carnitine is found in nearly all cells of the body and plays a critical role in fueling the production of energy. It transports long-chain fatty acids into the mitochondria so they can be oxidized, or burned, to produce energy. Carnitine also transports toxic compounds out of the cellular organelle, preventing any accumulation. Given these functions, carnitine is concentrated in tissues that utilize fatty acids as fuel, like skeletal and cardiac muscles.
For most people, the body makes a sufficient amount of carnitine, obtaining additional carnitine from their diets (The name “carnitine” comes from the Latin word “carnus,” meaning flesh, as it was first isolated from meat.) However, some people have genetic or medical conditions that prevent their bodies from meeting the necessary needs. This is when supplementation by oral supplement or IV is essential.
Carnitine occurs in two forms known as D-carnitine and L-carnitine. They are isomers (or mirror images) of each other. D-carnitine is not used in lipid metabolism, while L-carnitine does. L-carnitine is the active form found in the body that transports fat to cells to be used as fuel in metabolic processes. L-carnitine is synthesized in the brain, liver, and kidneys from the amino acids methionine and lysine and is critical to heart and brain function, muscle movement, and several other body processes.
When consumed, L-carnitine is absorbed in the small intestine and enters the bloodstream. Carnitine can be found in animal food sources such as meat, fish, poultry, and milk. Those who eat a diet that includes red meat and other animal products typically obtain about 60-180 milligrams of carnitine per day. Insufficient carnitine can lead to problems in the liver, heart, and muscles.
Carnitine is indicated in those with cardiovascular disease, renal (kidney) insufficiency, male infertility, diabetes, muscular disease, HIV/AIDS, and it also helps aid in athletic performance and aging.
There are no known side effects of carnitine when taken in normal doses. Some reported side effects include:
- – Nausea
- – Vomiting
- – Diarrhea
- – Stuffy nose
- – Restlessness
- – Insomnia
- – Body odor (“fishy” smell)
Some serious side effects may include:
- – Tachycardia (fast heart rate)
- – Hypertension (increased blood pressure)
- – Fever
There are no reported contraindications for carnitine. However, you should always speak with your doctor before taking carnitine.
According to the National Institutes of Health, carnitine interacts with pivalate-conjugated antibiotics such as pivampicillin which are used in the treatment of urinary tract infections. Taking these antibiotics increases the excretion of pivaloyl-carnitine, which can lead to carnitine depletion.
Carnitine also interacts with the anticonvulsants valproic acid, phenobarbital, phenytoin, or carbamazepine. Taking these have been shown to significantly decrease blood levels of carnitine. In addition, the use of valproic acid with or without other anticonvulsants may cause hepatotoxicity and increase plasma ammonia concentrations, leading to encephalopathy.
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