Posts tagged: amino acid

Health Benefits Of Arginine

Health Benefits Of Arginine
Graphic ©

Arginine is a semiessential amino acid whose indispensability sets in when critical illness and severe trauma occur; adults can produce this amino acid through the biosynthetic pathway, although its consumption from diet is still imperative to sustain satisfactory physiological levels our bodily functions require, especially in preterm infants who are incapable of natural arginine synthesis and in critically ill individuals with poor nutritional status and certain physical conditions. Similar to any amino acid, arginine is involved with protein synthesis and also increases growth hormone secretion, hence regulating immune function. Furthermore, arginine serves as the precursor of creatine, which in turn is used by the body for the growth and energy metabolism of muscles, nerve, and testes. [1] Arginine is a precursor as well for the synthesis of glutamate, polyamines, creatine, agmatine, proline and urea.

In general, a healthy person can easily replenish one’s own arginine supply, but once metabolic needs increase due to sickness and exceed more than what our arginine-producing mechanism can meet, extra amounts from diet and supplements can remedy the demand. Very good sources of arginine include turkey, pork, chicken, pumpkin seeds, soybeans, nuts (including peanuts) and egg white. [2]

Arginine and the Production of Nitric Oxide

There are many reasons why arginine is unanimously considered physiologically important in our bodies since this amino acid participates in numerous metabolic processes, but the foremost perhaps would be its role as the precursor (“building block”) for the body’s creation of nitric oxide. Nitric oxide serves as a neurotransmitter in the central nervous system, particularly in the brain, as a mediator of host defense in the immune system, and as a vasodilator and endogenous antiatherogenic molecule in the cardiovascular system. Nitric oxide is the chief form of the endothelium-derived relaxing factor as well. Böger (2007) notes that an intake of reasonably large doses of L-arginine either through our diets or intravenously leads to enhanced nitric oxide production in individuals exhibiting impaired endothelial function at baseline and to improved cardiovascular disease symptoms, as demonstrated in a number of controlled clinical trials. [3] Studies have demonstrated that systemic or oral intake of arginine enhances cardiovascular function, reduces blood pressure and decreases myocardial ischemia among patients with coronary artery disease. It also reduces renal vascular resistance in patients with high blood pressure and normal or insufficient kidney function. [1]

Arginine, Hormones, and Exercise

A number of recent studies have demonstrated that L-arginine, orally administered, at a tolerated dose range of 5-9 g, potently stimulates a dose-dependent increase in resting growth hormone responses. Notably, at least 100% of resting growth hormone levels is achieved upon oral arginine intake. [4] Furthermore, McConell (2007) reported that administration of L-arginine improves endothelial function in a range of disease states and elevates the levels of hormones such as plasma insulin, catecholamines, growth hormone, glucagon and prolactin. These in turn influence metabolism. Research evidence also points to L-arginine boosting the positive effects of exercise on capillary growth in muscles and insulin sensitivity. [5]

To date, a considerably good amount of data supports the claim that arginine can be regarded as an effective ergogenic aid or performance enhancer. The double-blind, placebo-controlled study of Camic et al. (2010), for instance, randomized fifty college-aged men into three groups, namely, those on placebo, on 1.5 g arginine, and on 3.0 g arginine treatment, to determine the effect of daily 4-week oral administration of arginine-based supplements on the physical working capacity at the fatigue threshold (PWCFT), which measures the ability of an individual to resist fatigue and hence his or her functional capacity. Results revealed significant mean increases in PWCFT among subjects on L-arginine supplementation but no change for the placebo group. [6]

Arginine and Wound Healing

Because arginine plays a role in protein synthesis, in cell signaling via nitric oxide production and in cell proliferation, its participation in wound healing comes as a no surprise. In fact, several studies have concluded that arginine supplementation can lead to normalization or improvement of wound healing, making supplementation with arginine either on its own or in combination with other amino acids a very reasonably attractive treatment option in the management and care of critically ill or traumatized patients. [7] In artificial incisional wounds in rodents and humans, arginine boosts wound strength and collagen deposition, but as of today, concrete data from robust clinical trials / human studies are still limited as regards the recommended safe dose of arginine to fulfill the metabolic necessities during wound healing and the efficacy of arginine supplementation in improving recovery from acute and chronic wounds. [8]

Arginine and Aging

The potential anti-aging benefits of arginine come from the various health-promoting effects this amino acid renders in the body, including its ability to reduct risk of heart and vascular disease, supporting healthy erectile function, immune response improvement and suppression of gastric hyperacidity. According to a number of human and experimental animal studies, exogenous L-arginine intake induces several pharmacological effects when administered in doses larger than what can be obtained through normal dietary consumption. [9]


[1] Tapiero H., MathÈ G., Couvreur P., Tew K. D. (2002). I. Arginine. Biomedicine & Pharmacotherapy. 56(9): 439-445.

[2] Arginine(g). USDA National Nutrient Database for Standard Reference Release 27.…/

[3] Böger R. H. (2007). The pharmacodynamics of L-arginine. Journal of Nutrition. 137(6 Suppl 2): 1650S-1655S.

[4] Kanaley J. A. (2008). Growth hormone, arginine and exercise. Current Opinion in Clinical Nutrition and Metabolic Care. 11(1): 50-54.

[5] McConell G. K. (2007). Effects of L-arginine supplementation on exercise metabolism. Current Opinion in Clinical Nutrition and Metabolic Care. 10(1): 46-51.

[6] Camic C. L. et al. (2010). Effects of arginine-based supplements on the physical working capacity at the fatigue threshold. Journal of Strength and Conditioning Research. 24(5): 1306-1312. doi: 10.1519/JSC.0b013e3181d68816.

[7] Witte M. B., Barbul A. (2003). Arginine physiology and its implication for wound healing. Wound Repair and Regeneration. 11(6): 419-423.

[8] Stechmiller J. K., Childress B., Cowan L. (2005). Arginine supplementation and wound healing. Nutrition in Clinical Practice. 20(1): 52-61.

[9] Gad M. (2010). Anti-aging effects of l-arginine. Journal of Advanced Research. 1(3): 169-177.

Health Benefits Of Alanine – The Performance Enhancing Amino Acid

Health Benefits Of Alanine - The Performance Enhancing Amino Acid
Health Benefits Of Alanine – The Performance Enhancing Amino Acid. Infographic © Photo sources – see foot of article

Before you hit the gym to build those muscles you are so aspiring for or do your routine daily run, jogging, or cycling, you might be interested to meet the “performance-enhancing” amino acid called alanine. Alanine is a hydrophobic nonessential amino acid widely occurring in high concentrations in its free state in plasma, and although the body can naturally synthesized it through a process known as transamination from pyruvate, [1] a healthy diet consisting of alanine-rich food items such as chicken, beef, pork, lamb, turkey, and whole eggs [2] wouldn’t hurt and in fact would contribute to a lean mass gain and increased physical performance according to studies. With respect to molecular structure, alanine is one of the most simplest amino acids, [3] but don’t let this misled you to consider alanine as a chemical with little utility in the body. Alanine helps ward off infections by increasing our immunity, is involved in sugar and acid metabolism, and supplies fuel to muscles and brain tissues. [1]

Alanine and Athletic Performance

Any person with an average computer skill to research the Internet can easily come into a realization that alanine’s primary role in the body is as a substrate of carnosine. Carnosine, a compound that occurs naturally in numerous tissues of the body, especially the muscles, and is synthesized from beta-alanine and L-histidine, is a major contributor to H+ buffering that occurs in high-intensity exercise. It is a cytosolic buffering agent with powerful, specific antioxidant and antihypertensive properties. [4] Because of the key function of alanine in carnosine synthesis, this amino acid has been incessantly the focus of sports performance research and has become a well-known ergogenic aid, that is, a performance-enhancing substance. To date, a number of studies have already positively associated beta-alanine supplementation and a delay in the onset of neuromuscular fatigue. Most notably, significant improvements have been recorded in athletic performance during multiple bouts of intense exercise and single bouts of exercise lasting more than 60 seconds, with no life-threatening side effects recorded thus far. [5]

Van Thienen et al. (2009) conducted a double-blind study to investigate beta-alanine administration’s effect on the sprint performance of cyclists at the end of a simulated cycling race. In this study, the group on oral beta-alanine supplementation had an increased peak power output of 11.4% during the final sprint. [6] In the 2008 study of Hoffman et al., who have explored the effect of 30-day beta-alanine supplementation on anaerobic measures of collegiate football players, the group on beta-alanine, as compared with placebo, were able to achieve higher training volume during the bench press exercise and other resistance exercises, combined with lower self-reported sense of fatigue, although when testing with high-intensity anaerobic exercises minimal improvement in fatigue levels was observed. [7] A similar study was performed by Kern and Robinson (2011), this time on the effect beta-alanine had on the anaerobic power output and body composition of not only collegiate football players but also wrestlers. The results of this double-blind, placebo-controlled study demonstrated that study participants belonging to the beta-alanine group displayed more desirable test results than the placebo group, with improvements in performance being greatest in football players taking beta-alanine (a reduction in 300-yard shuttle time and an increase in flexed-arm hang). Wrestlers who ingested and not ingested beta-alanine both lost weight, but an increase in lean mass was only observed in those on beta-alanine supplements. [8]

Alanine and Its Antioxidant and Antiatherogenic Effects

Alanine also provides long-term protection to cells against harmful agents, although the molecular mechanism underlying such process is yet to be further explored. A research team from Martin Luther University, Germany, had tested the influence of L-alanine on the cytotoxicity and the expression of antioxidant stress proteins, ferritin and heme oxygenase 1, using cultured human endothelial cells. In this study, L-alanine pre-treatment conferred cellular protection against cytotoxicity, elevating the proportion of endothelial cells that survived by 76%. A significant induction of ferritin protein synthesis and heme oxygenase activity were also found, suggesting a stimulated expression of such antioxidant “defense proteins” in the cells of living beings. [9]

Alanine and Diarrhea

A randomized double-blind controlled trial from the International Centre for Diarrhoeal Disease Research, Bangladesh, investigated the effectiveness of oral rehydration solution with L-alanine and glucose in treating acute diarrhea among patients suffering from dehydration due to Vibrio cholera- or Escherichia coli-caused diarrhea. The findings from this study indicated that the addition of alanine in oral rehydration solution resulted in better efficacy at decreasing the severity of symptoms and the need for fluids among patients than standard oral rehydration solution without alanine content. [10]


[1] L-alanine. PubChem, National Center for Biotechnology Information, U.S. National Library of Medicine.

[2] Alanine(g). USDA National Nutrient Database for Standard Reference Release 27.…/

[3] Alanine. Wikipedia.

[4] Quinn P. J., Boldyrev A. A., Formazuyk V. E. (1992). Carnosine: its properties, functions and potential therapeutic applications. Molecular Aspects of Medicine. 13(5):379-444.

[5] Artioli G. G., Gualano B., Smith A., Stout J., Lancha A. H. Jr. (2010). Role of beta-alanine supplementation on muscle carnosine and exercise performance. Medicine & Science in Sports & Exercise. 42(6): 1162-1173. doi: 10.1249/MSS.0b013e3181c74e38.

[6] Van Thienen R., Van Proeyen K., Vanden Eynde B., Puype J., Lefere T., Hespel P. (2009). Beta-alanine improves sprint performance in endurance cycling. Medicine & Science in Sports & Exercise. 41(4): 898-903. doi: 10.1249/MSS.0b013e31818db708.

[7] Hoffman J. R. et al. (2008). Short-duration beta-alanine supplementation increases training volume and reduces subjective feelings of fatigue in college football players. Nutrition Research. 28(1): 31-35. doi: 10.1016/j.nutres.2007.11.004.

[8] Kern B. D., Robinson T. L. (2011). Effects of ß-alanine supplementation on performance and body composition in collegiate wrestlers and football players. Journal of Strength and Conditioning Research. 25(7): 1804-1815. doi: 10.1519/JSC.0b013e3181e741cf.

[9] Grosser N. et al. (2004). Antioxidant action of L-alanine: heme oxygenase-1 and ferritin as possible mediators. Biochemical and Biophysical Research Communications. 314(2): 351-355.

[10] Patra F. C., Sack D. A., Islam A., Alam A. N., Mazumder R. N. (1989). Oral rehydration formula containing alanine and glucose for treatment of diarrhoea: a controlled trial. British Medical Journal. 298(6684): 1353-1356.

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Health Benefits Of Alanine
Health Benefits Of Alanine – The Performance Enhancing Amino Acid. Graphic ©

Health Benefits Of Aspartic Acid

Health Benefits Of Aspartic Acid
Graphic ©

Aspartic acid is a nonessential amino acid produced in our bodies under normal physiological conditions through transamination of oxaloacetate or from ornithine and citrulline in the urea cycle to meet our daily requirements. [1] It can exist in two forms, namely, (1) L-aspartic acid, which can function as a precursor or building block for the synthesis of a number of molecules, including proteins, oligopeptides, purines, pyrimidines, and nucleic acids, [2] and (2) D-aspartic acid. In general, aspartic acid is involved in enzyme active centers and in the maintenance of protein solubility and ionic character and, due to being a charged amino acid, contributes to the buffering properties of proteins responsible for pH homeostasis in our bodies. [3]

As aforementioned, we can naturally synthesize aspartic acid, although a dietary intake of the amino acid through various food sources and supplements can help promote sufficient, healthy levels of aspartic acid in the body. Good aspartic acid-rich food items include egg whites, soybeans and soy meal, fish, seaweeds, tofu, pork, and beef, among others. [4]

Aspartic Acid and the Production of Testosterone and Other Reproductive Hormones

D-Aspartic acid has been claimed to be of beneficial effects to infertile men requiring a boost in testosterone levels and even to athletic individuals. A 1996 Italian study established the relationship between D-aspartic acid and hormonal activities, reporting that in in vitro experiments, this amino acid triggers testosterone synthesis and, in in vivo experiments, accumulates in the pituitary gland and testes of experimental rodents with a simultaneous increase in blood levels of luteinizing hormone, testosterone, and progesterone. [5] Another Italian study from Second University of Naples investigated the role of D-aspartic acid in male steroidogenesis and the amino acid’s effect on testosterone-dependent secondary sexual characteristics, but this time in experimental green frogs rather than rats. Short-term in vivo experiments demonstrated that the amino acid builds up in the testes and its injection leads to an increase in testosterone levels in both testes and plasma. Administration of other amino acids such as L-aspartic acid, D-glutamic acid, and L-glutamic acid rather than D-aspartic acid proved ineffective in elevating testosterone levels, suggesting that this increase comes as a result of D-aspartic acid uptake. [6]

Aside from testosterone, D-aspartic acid is also involved in the release and synthesis of luteinizing hormone, which induces ovulation and corpus luteum development in women. Topo et al. (2009) explained that D-aspartic acid triggers an augmentation of luteinizing hormone and testosterone release in humans. Furthermore, as observed in the pituitary glands of rats, such release and synthesis of luteinizing hormone involves cGMP as a second messenger. [7]

Aspartic Acid and Fatigue

Aspartic acid takes part in the synthesis of glucose and, via its metabolism in the Krebs cycle, contributes to energy production; in fact, it is said that low levels of aspartic acid may translate to lowered energy-generating capacity in cells. [8]

Aspartic Acid as Performance Enhancers

Although scientific evidence for claims of aspartic acid being an efficacious ergogenic aid is limited, it is assumed that L-aspartic acid improves performance during prolong and short-term intense physical activities by acting as a substrate for energy production in the Krebs cycle, conserving glycogen stores, and promoting a faster rate of glycogen resynthesis. [9]

Aspartic Acid and Opiate Dependence

L-Aspartic acid has been suggested to be of value in the treatment of signs of opiate abstinence syndrome, as it has been observed to reduce the compulsory intake of opiates by addicts and minimize physical dependence on the drug. In the study of Sener, Ceylan, and Koyuncuoğlu (1986), 8 g of L-aspartic acid was administered to 31 opiate addicts for 7 days after their withdrawal from opiate and the appearance of signs of abstinence syndrome. The effects of L-aspartic acid were then statistically compared with those of chlorpromazine plus diazepam, a drug combination used since then in therapy to suppress abstinence syndrome. The results revealed that the intensity and duration of a majority of abstinence syndrome signs (13 out of 16 signs) were more alleviated and shortened among addicts on L-aspartic acid treatment. [10]


[1] Aspartic acid. Wikipedia.

[2] L-aspartic acid.

[3] Aspartic acid D (Asp). The Biology Project, Department of Biochemistry and Molecular Biophysics, University of Arizona.

[4] Aspartic acid(g). USDA National Nutrient Database for Standard Reference Release 27.

[5] D’Aniello A. et al. (1996). Involvement of D-aspartic acid in the synthesis of testosterone in rat testes. Life Sciences. 59(2): 97-104.

[6] Raucci F. et al. (2004). Testicular endocrine activity is upregulated by D-aspartic acid in the green frog, Rana esculenta. Journal of Endocrinology. 182(2): 365-376.

[7] Topo E. et al. (2009). The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats. Reproductive Biology and Endocrinology. 7:120. doi:10.1186/1477-7827-7-120.

[8] Neustadt J., Pieczenik S. (2009). Foundations and applications of medical biochemistry in clinical practice. Bloomington, IN: iUniverse. p. 160.

[9] L-Aspartic acid. DrugBank.

[10] Sener A. I., Ceylan M. E., Koyuncuoglu H. (1986). Comparison of the suppressive effects of L-aspartic acid and chlorpromazine + diazepam treatments on opiate abstinence syndrome signs in men. Arzneimittelforschung. 36(11): 1684-1686.