Carnitine: role, types and food sources
It plays a decisive role in conveying the long-chain fatty acids from the cellular cytosol into the mitochondria (organelles responsible for cellular respiration, in which most of the energy is produced using oxygen), where they can be used to produce Adenosine-Tri -Phosphate (ATP, the molecule that "stores" the energy).
In the organism, carnitine is more concentrated in the muscles and in the heart. The richest food sources of carnitine are of animal origin, above all: meat, offal, fish products, milk and derivatives, and few vegetables.
Given its crucial importance for life and health, carnitine is also produced endogenously; nevertheless, due to disease, special conditions and malnutrition, it can become a conditionally essential nutrient, requiring exogenous intake - food and dietary supplements.
In this regard, today numerous carnitine-based products are available, useful for filling an increased need or nutritional deficit, with physical and mental energy and ergogenic functions for sport. Food supplements based on L-carnitine, given its very low toxicity, in conditions of full health, are considered totally safe for consumption.and Propionyl-L-carnitine.
L-carnitine (LC), by injection or orally, is clinically indicated in the treatment of:
- Primary carnitine deficiency
- Secondary carnitine deficiency.
These deficiencies, very different from each other (some genetic, others subordinate to other disorders or treatments), can cause serious complications. The most important is cardiomyopathy, which is present in children suffering from primary genetic carnitine deficiency.
Causes of secondary carnitine deficiency include:
- Drugs or active ingredients for: antibiotic therapy, chemotherapy, antiviral therapy with zidovudine, valproic acid
- Hemodialysis, in which the alteration of the homeostasis of carnitine causes anomalies, and which can be resolved with the administration of L-carnitine.
Acetyl-L-carnitine (ALC) is present in the central nervous system (CNS) and has a structure similar to that of acetylcholine. It is essential for the synthesis of myelin, promotes the synthesis of the "Nervous Growth Factor" (NGF), is essential for the metabolism of glutamate (amino acid derivative), counteracts the pain mechanism.In fact, several studies have shown that treatment with acetyl-L-carnitine reduces neuropathic pain. Acetyl-L-carnitine has been proposed for the treatment of mechanical and inflammatory lesions of the peripheral nerves, in doses of 0.5-1.5 g / day, with which it could:
- Improve nerve morphology
- Optimize conduction
- Support regeneration
- Reduce the pain.
Propionyl-L-carnitine (PLC) has been proposed in the treatment of diseases such as:
- Peripheral arterial disease (PAD), in doses of 2-3 g / day orally, or 300-600 mg / day intravenously
- Congestive heart failure, to increase exercise tolerance, in doses of 2 g / day
The pharmacological properties attributed to propionyl-L-carnitine are:
- Anaplerotic effects (this means that, once taken, the PLC provides the cell with propionyl-CoA, a compound useful for the production of energy in the absence of acetyl-CoA, an event that typically occurs in the case of ischemia)
- Reduction of endothelial dysfunction.
Carnitine is more abundant in animal tissues than in plant tissues.
The carnitine present in foods is perfectly bioavailable and is more abundant in animal tissues than in plant tissues.
The main food sources of carnitine - but not the only ones - are black meat (game), red meat and offal. Other significant sources of exogenous carnitine are white meats (poultry, rabbit, etc.), fishery products, milk and its derivatives.
About 54 - 86% of dietary carnitine is absorbed in the small intestine and enters the bloodstream directly. An adult who follows a varied diet, including products of animal origin, takes about 60-180 milligrams (mg) of carnitine per day. (die). On the contrary, in the vegan diet this intake drops drastically and seems to be below 10-12 mg / day. It should be noted, however, that diets low in carnitine have a relative impact on the circulating content of this nutrient, since the kidneys are able to store it quite efficiently.
In the table below we report the carnitine content of some foods.
Beef steak, cooked, approx. 115 g
Minced meat, cooked, approx. 115 g
Cod, cooked, about 115 g
Chicken breast, cooked, approx. 115 g
Wholemeal bread, 2 slices
On average, omnivorous humans take on 2-12 μmol / day / kg of body weight, which represents 75% of the total content in the organism. The endogenous production (autonomous of the organism), on the other hand, has an importance of about 1 , 2 μmol / day / kg of body weight, which corresponds to 25% of the body's carnitine. In practice, ¾ of the necessary carnitine is taken exogenously - with food - and only ¼ is synthesized by the body.
Pure vegetarians, i.e. vegans, without food of animal origin derive from food only about 0.1 μmol 7 days / kg of body weight..