L-arginine is known as a semi-essential amino acid. Was first isolated from a lupin seedling extract in 1886 by the Swiss scientist Ernst Schultze. This aminoacid can be obtained from exogenous sources via blood circulation, from intracellular protein degradation, or by the endogenous synthesis of arginine.
L-arginine Human Health Importance and Benefits
L-arginine is used for heart and blood vessel problems including congestive heart failure, chest pain, coronary artery disease, hypertension. Also used for recurrent pain in the legs due to blocked arteries, reduced mental capacity in the elderly, erectile dysfunction, and male infertility. Also, L-arginine is added to enteral and parenteral feedings for burn, sepsis and trauma patients.
In the body, arginine is converted to nitric oxide, which relaxes the blood vessels. This lowers stress on the heart and develops circulation. L-arginine could have a favorable role in congestive heart failure, acting through the nitric oxide L-arginine pathway or by growth hormone increment. Three small-scale study enrolling a total of 70 participant with congestive heart failure (CHF) found that L-arginine at a dose of 5 g to 15 g daily could significantly improve symptoms as well as objective measurements of heart function. L-arginine may enhance cardiac performance in patients with congestive heart failure, according to a 2000 study reported in “Clinical Cardiology“. In a study, of 36 participants with heart disease found that use of L-arginine (in combination with antioxidant vitamins and minerals) at a daily dose of 6.6 g decreased symptoms of angina. A small-scale a study showed that use of arginine (700 mg 4 times daily) may support transdermal nitroglycerin treatment for angina. In addition, intravenous infusion of L-arginine reduces blood pressure in individuals with hypertension as well as healthy people.
L-arginine is a precursor of different compounds (spermidine, spermine and putrescine) that are thought to play a role in sperm motility. A normal semen sample should have a volume of 1.5-5.0 ml, with greater than 20million sperm/ml. L-arginine is an amino acid necessary in the replication of cells, and is considered substantial for male fertility. Researches have shown arginine improves sperm count and motility. For infertile men with sperm counts greater than 10 million per milliliter, some physicians recommend up to 4 g of arginine per day for several months. In 1973, researchers reported a study in which L-arginine was given to 178 men with low sperm count. 74% of the participants had significant development in sperm count and motility after taking 4 g/day for 3 months. Another study, researchers evaluated the clinical efficacy of L-arginine in 40 infertile men. Participants were given 80 ml of a 10-percent arginine HCl solution for 6 months. L-arginine supplement significantly developed sperm motility without any adverse effects.
L-arginine is converted in the body into a chemical named nitric oxide. Nitric oxide (NO) is a strong neurotransmitter that helps blood vessels relax and develops circulation. L-arginine used in combination with proanthocyanidins or yohimbine, has been used as a therapy for erectile dysfunction. A study reported in European Urology found that the combination of L-arginine and yohimbine improves erectile function. Study by researchers at Seminological Laboratory, and reported in the May issue of Journal of Sex and Marital Therapy in 2003 discovered that administration of Pycnogenol and L-arginine important enhances sexual function in men with erectile dysfunction. During the three-month study period participants received 3 ampoules Sargenor a day, a drinkable solution of the dipeptide arginyl aspartate. (equivalent to 1.7 g L-arginine). Throughout the second month, participants were additionally supplemented with 40 mg Pycnogenol 2 times per day; during the third month, the daily dosage was increased to 3 time 40 mg Pycnogenol. After one month of therapy with arginine, a statistically non significant number of 2 participant (5%) experienced a normal erection. Therapy with a combination of Pycnogenol and L-arginine for the subsequent month increased the number of men with restored sexual function to 80%. After the third month of treatment, 92.5% of the men experienced a successful erection. Treatment of erectile dysfunction with pycnogenol and L-arginine.
L-arginine has different immunomodulatory activities such as stimulating T- and NK (natural killer) cell activity and influencing pro-inflammatory cytokine levels. As a increase of the immune system, L-arginine stimulates the thymus and promotes lymphocyte production. T cells are produced in the thymus, an endocrine system gland located beneath the sternum in the upper area of the chest. Researchers have found that arginine can enhance the weight of the thymus, an effect that is directly correlated with an increase in the number of thymic T-lymphocytes. Animal-based research has shown that supplementing the diet with L-arginine increases T-lymphocyte count as measured by weight of the thymus gland.
In human breast cancer, supplement with L-arginine has been shown to enhance the quantity and cytotoxic activity of NK (natural killer) cells and LAK (lymphokine-activated-killer) cells. In healthy participants, administering 30 g of arginine daily for 3 days resulted in improved NK (natural killer) cells and LAK (lymphokine-activated-killer) cells. A average rise of 91% in natural killer cell activity and a average rise of 58% in lymphokine-activated-killer cell activity were observed. According to a study published in the journal Clinical Cancer Research; researchers have found that L-arginine may reactivate cancer-fighting T-cells in glioblastoma patients, allowing reactivation of the immune system to fight cancer progression. L-arginine/omega-3 fatty acids / RNA supplements, strengthens the immune system. In one study involving 42 people who had undergone gastrointestinal operation for cancer, it was found that the number of T cells increased. On the tenth day after surgery, the patients receiving the supplement posted an activated T-cell count of 132 cells per milliliter, versus 81 cells/ml in the control group an development of 63%; by day 16 after surgery, the development was 92%. According to research published in the Journal of Nutrition Biochemistry; indicate that the combination of vitamin C and L-arginine interferes with specific chemical reactions that affect the survival of cancer and tumor cells.
L-arginine taken in combination with lysine has been shown beneficial in treating people subjected to high levels of mental stress and anxiety, in a clinical study, involving 108 Japanese adults. Anxiety was significantly decreased, and basal levels of the stress hormone cortisol were reduced. A study reported in the June 2005 edition of the journal, “Nutritional Neuroscience” demonstrated that a combination of L-arginine and L-lysine helped to decrease the effects of stress in study participants with high trait anxiety who were exposed to a simulated stress test.
HGH (Human Growth Hormone)
Arginine has been shown to stimulate the pituitary gland to produce and secrete HGH (Human Growth Hormone) in young males, at a dose of 3 g daily. L-arginine, rises growth hormone by blocking a natural inhibitor of Human Growth Hormone, according to a Feb 2002 published in the European Journal of Endocrinology. A study at the “Division of Endocrinology at the University of Turin” involving normal adults aged 66-82 who tripled the level of Human Growth Hormone in their blood after application of 30 g injections of arginine. L-arginine has been approved by the FDA to test for specific human growth disorders. In these tests, arginine is injected into the body (acromegaly, panhypopituitarism, gigantism).
Arginine is considered one of the important muscle building supplements designed to help body synthesize more protein needful for accelerated muscle gain and developed stamina. In advanced years, HGH is responsible for maintaining muscle mass and increasing fat metabolism. Through its capability to enhance growth hormone secretion, arginine may stimulate muscle growth. L-arginine is utilized for creatine biosynthesis in the body. Creatine is important for energy metabolism in skeletal muscle and other organs. It is converted to a high-energy phosphate format, known as phosphocreatine. According to a research from the July 2010 edition of Amino Acid, increased L-arginine intake may enhance muscle mass and decrease body fat.
Wasting syndrome is a frequent complication of HIV disease. The AIDS wasting syndrome shares many features with the cachexia seen in cancer or sepsis. Wasting is related to illness progression and death. Some researchers forecast that 20 percent of HIV-positive patients will experience wasting. L-arginine is believed to affect muscle proteolysis. The combination of L-arginine, glutamine, and the amino acid derivative, HMB (hydroxymethylbutyrate), may avoid loss of lean body mass in people with HIV/AIDS linked wasting. In a clinical study, AIDS patients who had lost 5% of their body weight in the previous 3 months received either placebo or a combination containing 1.5 grams of HMB (hydroxymethylbutyrate), 7 g of glutamine, and 7 g of arginine twice daily for 8 weeks. Those supplemented with placebo gained an average of 0.37 pounds, usually fat, however lost lean body mass. Those taking the nutrient combination gained an average of 3 pounds, 85% of which was lean body weight. New researches carried out at University Hospital, Geneva, Switzerland have shown favorable effects using L-arginine and omega 3 fatty acids on patients who have symptoms of wasting. The HIV Wasting Syndrome.
L-arginine has been examined at doses of 6 to 30 g/day for a different of ailment.
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