Arginine with symbol Arg or R is also known as L-arginine, an α-amino acid which is used in protein biosynthesis. It encloses an α-carboxylic acid group, α-amino group and a side chain which consists of a 3-carbon aliphatic straight chain ending in a guanidino group. Amino group is protonated (-NH3+) Carboxylic acid is deprotonated (-COO-) which makes arginine a charged and aliphatic amino acid. It is a precursor for biosynthesis of nitric oxide. It is encoded by codons CGU, CGA, CGC, AGA, CGG, and AGG.
Arginine is categorized as conditionally essential or semi-essential amino acid which depends on developmental stage or health status of individual. Infants (preterm) are not able to synthesize or form arginine internally which makes this amino acid nutritionally imperative for them. Healthy people does not require supplement of arginine as it is a component of all protein foods and could be synthesized in the body from glutamine by citrulline.
History
Initially, arginine was isolated in 1886 from lupin or pumpkin seedlings by German chemist Ernst Schzule and his assistant Ernst Steiger. Ernst Winterstein and Ernst Schulze (1865-1949) concluded the structure of arginine. Winterstein and Shulze amalgamate arginine from ornithine and cyanamide in 1899 but certain doubts about structure of arginine drifted until Sørensen’s synthesis of 1910.
Dietary sources of Arginine
| Food name | Weight (g) | Arginine (g) |
| Turkey | 863 | 16 |
| Lupins | 180 | 6 |
| Soybeans | 186 | 5 |
| Butternut | 120 | 5 |
| Spirulina | 112 | 4 |
| Peanuts | 146 | 4 |
| Black walnut | 125 | 4 |
| Sesame seeds | 144 | 3 |
| Hyacinth beans | 210 | 3 |
| Almonds | 143 | 3 |
| Winged beans | 182 | 3 |
| Pine nuts | 135 | 3 |
| Brazilnuts | 133 | 2 |
| Kielbasa | 370 | 2 |
| Yardlong beans | 167 | 2 |
| Kidney beans | 184 | 2 |
| Cowpeas | 167 | 2 |
| Pistachio | 123 | 2 |
| Chicken | 145 | 2 |
| Tuna | 146 | 2 |
Health Benefits of Arginine
This amino acid is essential for overall health and let’s know some:
- Circulatory health
Circulatory system comprises of heart and various blood vessels contained within body and are responsible to deliver nutrients and oxygen to cells which require it. Low supply of oxygen and nutrients to cells which results lower metabolic function. L-arginine is required for production of nitric oxide which assists blood vessels to relax and lower pumping pressure of heart. People with low level of arginine are more prone to suffer high blood pressure and heart failure because heart is being unable to meet demand of working cells.
- Helps to lose weight
Study shows that diet with high L-arginine have high lean body mass and promote burning off excess fat. The mechanism seems to include regulation of insulin which is a hormone that assists efficient discharge of glucose from blood. It lowers the chances of glucose being stored as fat but used for production of energy.
- Enhance performance
L-arginine is a well-known supplement used by athletes considered as ergogenic acid. Ergogenic acid helps to improve performance naturally by enhancing strength output and resistance to fatigue. Study shows that elder persons who consume more arginine have fewer chances to suffer from fractures and falls as a result of reduced muscle mass.
- Anti-aging activity
L-arginine enhances synthesis of growth hormone as we sleep. Growth hormone ensures that cells are repaired effectively so its functions could be maintained at optimum levels. Yet synthetic growth hormone decline to live up effects of naturally synthesized growth hormones which makes a better effect to promote levels by increment of L-arginine intake. L-arginine supplement has anti-aging activity.
- Normalize blood pressure
Something which promotes health of circulatory system is beneficial for blood pressure. L-arginine assists in stimulating production of endothelial nitric oxide synthesis that impacts directly to blood vessels ability to soothe. People with high consumption of L-arginine improve the level of blood pressure by lowering overall cardiac hazard significantly in the process.
- Control blood glucose
Diabetic patients who use L-arginine have better control over their level of blood glucose. L-arginine assist sugar metabolism so there is less present in blood stream at any time. Supplements of L-arginine improve insulin sensitivity. Insulin is a hormone which enhance uptake of glucose into cells that require it. Typically diabetics acquire reduced insulin sensitivities that favor glucose storage as fat instead of being used in cells which require them. It helps to lower diabetic complications as a result of elevated levels.
- Promotes recovery
Low collagen synthesis rate results longer time period to heal wounds. Yet, L-arginine helps to speed up healing of wounds. It synthesize other amino acid called L-proline. Proline is a step in collagen synthesis which is a protein accountable for skin and structural health. It also promotes reduction of pain or swelling by improving blood flow.
- Hair health
L-arginine helps to promote nitric oxide levels by promoting blood flow to scalp and follicles which require them. Debilitate blood flow is a major cause of hair loss in both women and men. Men are more likely to feel brunt of it as a result of DHT lowering blood flow to follicles. Though L-arginine is not able to reverse hair loss effects completely but shows improvement by regular consumption patterns in male pattern baldness or woman.
- Treatment for erectile dysfunction
Men with erectile dysfunction have impaired blood flow to penis and suffer from some pre-existing vascular deficits. L-arginine is helpful to stimulate production of nitric oxide from within walls of blood vessels. This is why supplements with L-arginine are regarded as an effective treatment.
- Strengthen immunity
L-arginine helps to speed up healing of wounds and stimulates immune system. It helps to lower chances of infection and could improve detection of precancerous cells and also suppress allergies or asthmatic attacks before it occur. It vitalizes both leukocytes MST cells and T cells which are essential for preventing cancer.
Side effects of L-arginine
L-arginine might cause some side effects such as gout, bloating, abdominal pain, airway inflammation, diarrhea, low blood pressure, blood abnormalities, allergies and worsening of asthma. People with low blood pressure, heart disease, kidney problems, and diabetes should consult doctor for using L-arginine.
References:
https://en.wikipedia.org/wiki/Arginine
https://pubchem.ncbi.nlm.nih.gov/compound/L-arginine#section=Top
http://www.newworldencyclopedia.org/entry/Arginine
https://www.medicalnewstoday.com/articles/318174.php
https://www.selfhacked.com/blog/l-arginine/
https://www.naturalfoodseries.com/10-benefits-arginine-l-arginine/