Arginine, or arginine amino acids, are a group of more than twenty amino acids which are required for the synthesis of many biological proteins and enzymes. It is usually sourced from foods, especially meats, poultry, fish, dairy products, seeds, nuts, and herbs. Arginine is used to treat many inflammatory diseases and is essential in sustaining life in all mammals (including humans). Although not required in sufficient quantities in the human body, arginine is synthesized by the pancreas, liver, kidneys, gastrointestinal tract, lungs, skin, bladder, bowels, heart, and brain. Because of this, there has been an increased interest in the role of supplements in treating and preventing age-related illnesses and diseases.
Nitric oxide plays an important role in maintaining the smooth function of the arteries, a vital part of the circulatory system, as well as other vital organs like the liver. In recent years, the effects of nutritional supplementation with arginine amino acids have been investigated for their possible benefits in preventing arteriosclerosis and improving blood flow. Preliminary data have indicated a reduction in vessel plaque buildup in patients with mild atherosclerosis. Furthermore, nitric oxide has been reported to improve blood flow through dilated arteries. Studies in animals have indicated that the nitric oxide supplements can improve survival and performance in injured athletes.
The recommended daily allowance of arginine is two grams for adults and six grams for children.
However, studies investigating the effect of l-arginine on nitric oxide in the circulatory system found that this addition did not significantly improve blood flow or oxygenation in the vessels. Because the addition of arginine can cause gastrointestinal upset, care should be taken when taking this supplement to avoid bleeding and ulcer formation. However, in studies investigating the effect of l-arginine on cholesterol levels, arginine has been shown to help reduce levels of bad (HDL) cholesterol.