Arginine is a non-essential amino acid, which means that the body is able to produce it itself from other amino acids (citrulline for example). Being non-essential on the other hand does not mean that an exogenous contribution has no interest because arginine has many interests both in improving physical performance and on health via its roles on blood circulation and hormone production.
Sources of arginine
Although the body is capable of producing arginine, this amino acid is sometimes referred to as semi-essential because sometimes endogenous synthesis is not sufficient to cover requirements. This is why it is sometimes necessary to supplement it through the diet or food supplements to ensure that the body functions properly. But which foods contain arginine?
Meats
Meat is an interesting source of arginine. Poultry in particular, because up to 1. 9% can be found in turkey or chicken 1. Among the sources of animal origin, pork is also rich in arginine with a quantity of around 1. 9%. This is slightly more than beef, which contains an average of 1. 7% 1
Seeds and nuts
This amino acid is found in large quantities in many seeds and nuts, in fact nuts themselves, almonds or sesame seeds can contain up to 3g of arginine per 100g! But the most concentrated food seems to remain the pumpkin seed which contains up to more than 5g per 100g! The problem is that it is not easy or advisable to consume such quantities of seeds, because of the carbohydrate or fat intake that this can represent.
Legumes
Naturally rich in protein, legumes are rich in amino acids and some in arginine. This is particularly true of lentils and chickpeas, which can contain up to 2g per 100g of arginine.
There are also other foods such as brown rice and other cereals that contain this amino acid. The problem is that in order to get health benefits, the doses often have to be higher than the amounts provided by the diet.
This is where arginine-based food supplements (Arginine HCL, AAKG. . . ) are interesting.
The benefits of this amino acid are indeed very numerous.
Arginine and physical performance
Congestion
Arginine is very often used by bodybuilders with training. This is because arginine has the ability to increase vasodilation, allowing for better congestion also known as "pumping". Plasma arginine is a precursor to a compound called nitric oxide. The latter has the capacity to improve vasodilation by relaxing the endothelial cells of the blood vessels, thus increasing their diameter.
However, arginine supplementation is difficult to increase plasma arginine and therefore nitric oxide production. Unless it is combined with citrulline supplementation.
Endurance
Because of its potential action on the production of nitric oxide and the dilation of blood vessels, the muscle is better irrigated. As a result, the muscle and muscle cells are better supplied with the nutrients and oxygen that are essential for their functioning.
Some efforts are very demanding in terms of energy and oxygen, but they can also lead to a significant production of lactic acid. This component is a waste product produced during anaerobic (without oxygen) lactic effort which causes a burning sensation, muscle pain and cramps if it remains in the muscle for too long. Vasodilatation therefore helps to better manage and eliminate the excess lactic acid and thus mitigate the side effects of these metabolic processes.
Muscle development
Once ingested, arginine has the ability to stimulate the pituitary gland which is responsible for the production of growth hormone 5. This stimulation increases the levels of growth hormone circulating in the body. This is known to stimulate the recovery of muscle cells damaged by training, and also muscle growth. Apart from its role in anabolism, growth hormone is involved in many metabolic processes. It also regulates the metabolism, reduces body fat and optimises the functioning of the organs. 6.
Arginine and health
Blood pressure
Hypertension is a major cause of morbidity and mortality, as it can lead to serious problems such as stroke or cardiac arrest. Although genetics play an important role in the development of hypertension, nutrition is also very important. Indeed, high blood pressure is associated with altered nitric oxide metabolism and high oxidative stress. Since arginine regulates nitric oxide levels, it is linked to the risk of developing hypertension. Indeed, one study showed that arginine supplementation increases nitric oxide synthesis and improves endothelial function in subjects with hypertension 7.
Erectile dysfunction
Sexual function is regulated in part by the ability of the penis to fill with blood. And so, erectile dysfunction can be the result of the vessels having difficulty carrying blood to the reproductive organ. Because of arginine's action on nitric oxide synthesis, supplementation may help to promote blood flow to the penis.
In men with low levels of nitric oxide, a study has shown that a daily intake of 5g of arginine improves the quality of erections.
The immune system
Arginine is an amino acid that has been used for many years, often in combination with other substances, to boost immunity. Studies have shown a link between arginine metabolism and the action of myeloid cells (cells that give rise to immune components). Indeed, arginine would have the capacity to prevent the accumulation of MSC (Myelin suppressor cells). These cells are very present in tumour cells and their function is to destroy the myeloid cells and thus disturb the immune system. Treatment with arginine therefore contributes to the proper functioning of this part of the immune system 9.
Kidney function
The catabolism of proteins leads to the production of ammonia, a toxic compound that must be eliminated by the kidneys through the urea cycle. If this substance is not eliminated, it can lead to undesirable effects in the long term. As arginine is involved in the urea cycle, it helps to detoxify the kidneys and thus better manage this metabolic waste product 10.
In summary, this amino acid has many beneficial effects often linked to its ability to stimulate nitric oxide activity. Whether it is for muscle growth, muscle soreness due to exercise, sexual function or blood pressure, arginine has shown positive results in numerous studies.
Finally, although it has few known side effects to date, it is best to consult a health professional before taking arginine if you have heart or kidney problems to avoid any adverse effects.
Bibliography
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4. Korthuis RJ. Skeletal Muscle Circulation. San Rafael (CA): Morgan & Claypool Life Sciences; 2011. Chapter 4, Exercise Hyperemia and Regulation of Tissue Oxygenation During Muscular Activity.
5. Scott R. Collier. Growth hormone responses to varying doses of oral arginine. Growth Hormone & IGF Research April 2005,Volume 15, Issue 2, Pages 136-139
6. Frisch H. Growth hormone and body composition in athletes. J Endocrinol Invest. 1999
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8. Klotz T, Mathers MJ, et al. Effectiveness of oral L-arginine in first-line treatment of erectile dysfunction in a controlled crossover study. Urol Int. 1999;63(4):220-3.
9. Petar J. Popovic, Herbert J. Zeh, Juan B. Ochoa, Arginine and Immunity, The Journal of Nutrition, Volume 137, Issue 6, June 2007, Pages 1681S-1686S
10. Zieve L. Conditional deficiencies of ornithine or arginine. J Am Coll Nutr 1986;5:167-76
