What is carnitine and what it is used for

It was 1905 when, for the first time, the name of carnitine appeared in a scientific publication . More than a century later, it certainly cannot be said that this molecule has gone out of fashion: hundreds of papers are published by the scientific community every year.

But let’s start from the beginning: what exactly is carnitine and why is it so important for our body?

At a chemical level, carnitine is made up of an amino group and a carboxylic group but it is not an amino acid because it does not form proteins. It is not even a vitamin (despite having a similar structure), because the body is able to synthesize it. 

This unique molecule is found almost entirely in the heart , with the exception of 2% which is found in the  liver and  kidneys . 
Carnitine is used to transport long-chain fatty acids from the cytoplasm (the fluid contained in the cell membrane) to the mitochondria (organelles present in our cells), where they are subjected to oxidation to obtain ATP . 

All cells produce ATP , starting from nutrients and in the presence of oxygen. And ATP (adenosine triphosphate) is nothing more than a nucleotide that releases the energy that allows all our cells, organs and tissues to keep us alive.

It is estimated that a man weighing 70 pounds, at complete rest, needs 40 pounds of ATP per day . During intense physical activity the need soars, reaching 500 grams per minute. With such a need, it is clear that ATP must be built and rebuilt continuously. On average, each of us produces 139 kilos every day , largely thanks to carnitine. 

The three forms of carnitine

More than carnitine, we should actually talk about carnitine , even if the most studied molecules, in addition to L-Carnitine, are its derivatives Acetyl-L-Carnitine and Propionyl-L-Carnitine which have the same biological properties but different uses: 

> L-Carnitine should be taken in case of primary and secondary carnitine deficiency;

> Acetyl-L-Carnitine , present in the central nervous system and with a structure similar to that of acetylcholine, is indicated in case of mechanical and inflammatory lesions of the peripheral nerve;

> Propionyl-L-Carnitine should be administered in case of peripheral arterial disease and heart failure. 

Inside the cell, Acetyl-L-Carnitine and Propionyl-L-Carnitine both transform into L-Carnitine, but the former has a greater affinity for brain tissue , while the latter has a greater affinity for muscle tissue. 

How we take carnitine

Under normal conditions, our body synthesizes 25% of the carnitine requirement and obtains the remaining 75% from food .

The main sources of carnitine are meats such as sheep, lamb, beef, pork and rabbit; secondly, there are cheeses , which however have a much lower content, and some vegetable sources .

To be able to absorb it, the presence of vitamin C , niacin, vitamin B6 and iron is essential . It should also be remembered that the precursor of carnitine is lysine , an amino acid present in legumes .

It goes without saying that without carnitine we could not live , and heavy imbalances in the carnitine system can trigger serious diseases (insulin resistance, muscle weakness, dyslipidemia, diabetes  and heart problems). 

But there are also many other cases in which the deficit is milder and causes us tiredness, physical and mental fatigue, reduction of muscle mass and loss of appetite. In this case, for example  , taking food supplements can significantly improve our quality of life .