Carnitine: what it is, functions and benefits

What is carnitine?

Carnitine is an amino acid or quaternary amine, it is an essential molecule for its indispensable physiological action in metabolism, being present in many animal species.

For its synthesis in the liver, kidneys or brain, it requires the combination of essential amino acid compounds, mainly lysine and methionine as well as ascorbic acid, niacin, pyridoxine and iron.

Note: It is generally consumed directly from foods of animal origin, although vegetables also contain it but in small quantities. Exogenous carnitine, i.e. through supplements, can also be consumed in special situations.

What are the functions of carnitine in the body?

The basic function of the also calledL carnitine, is related to the production of energy necessary for the functioning of cells, in addition to the balance in the use of energy sources. Here are the most outstanding features:

1. Metabolize fats

Its basic function consists of the transport of long-chain fatty acids such as eicosapentaenoic acid (EPA) anddocosahexaenoic acid (DHA), activated from the cytosol to the mitochondrial matrix, where they are oxidized to obtain energy. This is how an article entitled “Carnitine in sport” describes it. (1)

In addition, another scientific study titled “Oxidation of long- and medium-chain fatty acids increases in exercise-trained human skeletal muscle,” describes the influence of carnitine on long-chain fatty acids on transport to the mitochondria of cells during physical exercise. (2)

2. Reduce oxidative stress

In the mechanism of ATP production, carnitine palmitoyltransferase binds L-carnitine molecules to long-chain fatty acids, discarding short-chain fatty acids improving mitochondrial function, reducing oxidative stress, a process that allows the release of proinflammatory cytokines during situations that can impair cellular energy homeostasis.

To highlight: Carnitinehas antioxidant effects as it eliminates free radicals, particles that if accumulated in excess alter DNA and damage cells by oxidation. In this sense, a scientific article describesthe antioxidant action of L carnitine in laboratory-induced oxidative stress. (3)

3. Decrease lipid accumulation in the liver

Lipogenesis is thebiochemical reaction that occurs in the body, specifically in the liver, and consists of the synthesis of esterified long-chain fatty acids to form triglycerides or reserve fats.

In this sense, carnitine decreases the synthesis of these fatty acids (lipogenesis) in the liver through the diversion of acetyl remains to acetyl-carnitine, which is subsequently released by the liver into the bloodstream, which generates adecrease in the accumulation of free radicals.

4. Protect mitochondrial function

The function of mitochondria is togenerate enough energyto activate the metabolism of the cell, through the production of adenosine triphosphate or ATP.

The capacity of the mitochondria can be exceeded whenlarge amounts of fatty acids are mobilizedto meet energy demand, for example in sports activities.

To highlight: The action of L-carnitine is that itcontrols the access of excess fatty acidsthat cannot be used, reducing the formation of ketone bodies and stimulating the oxidation of glucose, thus preventing free radicals from forming.

What are the benefits of carnitine?

Thevarious benefits of carnitine have focused on theproduction ofenergy for the body, especially those that require a special energy intake. Here are the most relevant ones:

1. Transform fat into energy

In physical work inmoderate-intensity sports activity, long-chain fatty acids are mobilized and begin to betransported to the muscle.

They are then taken to the mitochondria, usingL carnitine molecules as a transport vehicleand will later be oxidized to be used as energy in ATP molecules.

2. Increase physical performance

The main effect of this amino acid is that in sports activities of high intensity and long duration, it allows themitochondria to generate energy from fatty acids, reserving the glycogen of the muscles. This mechanismallows there to be a significant increasein physical performance when performing sports exercise.

Note: In the case of high-performance athletes, the daily intake of this amino acid should be done exogenously through the use of supplements.

3. Promotes muscle recovery

L carnitine uses fat as energy in sports activities in endurance sports, through the reduction of the use of carbohydrates by the muscles.

In this way, it helps to store muscle glycogen, with an immediate effect, delaying fatigue and lengthening the time and quality of workouts, especially those of long duration and high intensity.

4. Maintains muscle mass

In recommended doses, this amino acid protects muscles from degradationthat occurs due to slimming diets or lack of protein, being a powerful anticatabolic. This amino acid through physical activity, maintains the tone of the muscles, preventing their catabolization.

What are the foods that contain carnitine?

Themain source of this amino acidis foods of animal origin, especially lean meats and other plant sources. We mention the most important ones:

1. Meats

The main source of this amino acid in important concentrations arefoods of animal origin, especially beef, fish, chicken or pork.

A study on “Novel knowledge about meat intake and prevention of sarcopenia: all the reasons for adequate consumption”, states that through this foodamino acids such as carnitine are obtained that are importantto prevent sarcopenia. (4)

2. Dairy products

Milk productssuchas low-fat cheeses, butter among others, providesignificant concentrations of this amino acid.

Important: The consumption of skimmed or skim milk is recommended, so that the intake of unsaturated fats is avoided.

3. Cereals

Cereals contain few concentrations of this amino acid, however their consumption is conducive as they provide other nutrients that contribute to the synthesisof this amino acid in the liver.

4. Vegetables and fruits

Likewise, vegetables and fruits have alow contribution of carnitine, due to their minimum protein value, however, the nutritional composition of these foodsallow them to provide other nutrientsrequired by both the liver and kidneys to synthesize this amino acid.

Key Findings

• Carnitine is anessential amino aciddue to its action on metabolism.
• The main function of carnitine is thetransport of fatty acidsinto the mitochondria to produce energy.
• The foods with the best concentrations of this amino acid aremeats.
• Thanks to this amino acid,physical performancein athletes is increased.
• It promotesmuscle recovery, especially in high-intensity sports activities.
• In case of consuming carnitine in supplement form, it is necessaryto consult the doctorto avoid unwanted effects.