Citrulline is a nonessential amino acid, which means that it is manufactured from other amino acids in the liver; it does not have to be obtained directly through the diet. Citrulline is found in high concentration in the liver. Citrulline is not a component of any major proteins or enzymes. It is synthesized in the body from ornithine by the addition of CO2 and ammonia and is a precursor of arginine. Only the L form of amino acids are constituents of protein.
Citrulline exists primarily in the liver, where it is heavily involved in the urea cycle to detoxify and excrete ammonia. This unusual amino acid is formed in the urea cycle by the addition of carbon dioxide and ammonia to ornithine. Next, it is combined with aspartic acid to form arginosuccinic acid, which later is metabolized into the amino acid arginine. Citrulline is not a component of any major proteins or enzymes. This unusual amino acid is formed in the urea cycle by the addition of carbon dioxide and ammonia to ornithine. Next, it is combined with aspartic acid to form arginosuccinic acid, which later is metabolized into the amino acid arginine. Citrulline is not a component of any major proteins or enzymes.
Function and Benefits of Citrulline
- Promotes energy
- Stimulates the Immune system
- Metabolized to form L-Arginine
- Detoxifies ammonia
- Citrulline helps the immune system in fighting infections and increases energy.
- Citrulline, through its conversion into another amino acid (arginine) in our body optimizes blood flow. Arginine allows for increased production of nitric acid in the endothelium, to support circulatory function.
- Without citrulline it is not possible to detoxify liver cells from ammonia, which is a waste product of oxidation process.
- It helps maintain the acid-base balance in the body.
- It plays an important role in the production of arginine, which stimulates the secretion of human growth hormone and prolactin. Arginine helps in bodybuilding, in enhancing blood flow and in relieving stress.
- Citrulline promotes the production of insulin, creatine and the growth hormone.
- Watermelon, especially the melon rind is an excellent source of citrulline. Vegetables like pumpkins, cucumbers, gourds and squashes are also good sources of citrulline.
- Besides vegetables, fruits such as cantaloupes, honeydews, bittermelons and muskmelons also contain citrulline in substantial amounts.
- Walnut seedlings are considered to be the richest source of citrulline.
- Citrulline is also abundantly found in fish, meat, eggs, milk, and legumes.
- Foods rich in protein, also contain high amount of citrulline.
Serine is is a nonessential amino acid. Serine was first isolated in 1865 from sericin, a silk protein, it can be synthesized in the body from glycine , but this process requires the presence of sufficient amounts of vitamins B3 and B6 and folic acid. Glycine is converted into serine by the addition of hydroxymethyl group and this reaction is catalyzed by serine hydroxymethyl transferase enzymes which also requires the two coenzymes namely, tetrahydrofolate and pyridoxal phosphate.
Serine is required for the metabolism of fat, tissue growth and the immune system as it assists in the production of immunoglobulins and antibodies, and is a constituent of brain proteins and nerve sheaths. It is important in the production of cell membranes, and muscle tissue synthesis. It is important in RNA and DNA function, cell membrane formation, and creatine synthesis. Cancer-preventative. However, too-high serine levels in the body may have adverse effects on the immune system.
Function and Benefits of Serine
- Serine is required for the metabolism of fat, tissue growth and the immune system as it assists in the production of immunoglobulins and antibodies. Some derivatives (e.g. ethanolamine) are also important components of the phospholipids found in biological membranes.
- It performs an important function in the catalytic role of numerous enzymes, for example it has been found to occur in the active sites of trypsin, chymotrypsin and various other enzymes.
- Serine is also utilized in the synthesis of tryptophan amino acid which then gives rise to important neurotransmitter the serotonin in the central nervous system. Their deficiency leads to depression, irritability, insomnia, anxiety and confusion.
- Serine has found to increase the absorption of creatine. Creatine is important for muscles as it make them strong and increases their mass.
- It is a component of brain proteins and the protective myelin sheaths that cover nerve fibers. It is important in RNA and DNA function, cell membrane formation, involved in the metabolism of purines and pyrimidines, and muscle synthesis
- Serine can be made from glycine in the body, but this process requires the presence of sufficient amounts of vitamins B3 and B6 and folic acid
- It is also used in cosmetics as a skin moisturizer.
- Serine stimulates the synthesis of glucose (blood sugar) in the liver. For this reason, eating proteins foods that are rich in serine will help stabilize the body against oscillations of blood sugar levels after eating. Serine is known to be the precursor to cysteine, along with methionine.
Deficiency leads to depression, irritability, insomnia, anxiety and confusion.
Rich Food Sources of Serine
- Animal origin sources: These include : meat, beef, dairy products like cheese etc.
- Plant origin sources: These include : almonds, asparagus, chickpea, cow pea, flax-seed, lentils, sesame seed, walnut and soy beans.
Ornithine is a nonessential amino acid and is manufactured by the body. The amino acid, arginine, is metabolized during urea production and is required by the body as it acts as a precursor of citrulline, proline and glutamic acid. Ornithine induces the release of growth hormone in the body, which in turn helps with fat metabolism. It is required for a properly functioning immune system and liver and assists in ammonia detoxification and liver rejuvenation. Helps in healing and repairing skin and tissue.
Ornithine plays an important role in the urea cycle and is the precursor of the amino acids citrulline, glutamic acid, and proline. Another primary role of ornithine is being an intermediate in arginine biosynthesis, although this is due to its participation in the urea cycle (responsible for the production of urea). Ornithine is not directly incorporated into proteins and enzymes and does not have a codon in the genetic code.
Functions and Benefits of Ornithine
- Induces the release of growth hormone in the body, which in turn helps with fat metabolism. It is required for a properly functioning immune system and liver and assists in ammonia detoxification and liver rejuvenation. Helps in healing and repairing skin and tissue.
- Ornithine is necessary for proper immune-system and liver function.
- High concentrations of ornithine are found in the skin and connective tissue, making it useful for promoting healing and repairing damaged tissues.
- Ornithine is synthesized in the body from arginine, and in turn serves as the precursor of citrulline, proline, and glutamic acid.
- Animal research has suggested that ornithine, along with arginine, may promote muscle-building activity in the body by increasing levels of growth-promoting (anabolic) hormones such as insulin and growth hormone. However, most human research does not support these claims at reasonable intake levels. One study that did demonstrate increased growth hormone with oral ornithine used very high amounts (an average of 13 grams per day) and reported many gastrointestinal side effects. One controlled study reported greater increases in lean body mass and strength after five weeks of intensive strength training in athletes taking 1 gram per day each of arginine and ornithine, compared with a group doing the exercise but taking a placebo. These findings require independent confirmation.
- Ornithine aspartate has been shown to be beneficial in people with brain abnormalities (hepatic encephalopathy) due to liver cirrhosis. In a double-blind trial, people with cirrhosis and hepatic encephalopathy received either 18 grams per day of L-ornithine-L-aspartate or a placebo for two weeks. Those taking the ornithine had significant improvements in liver function and blood tests compared with those taking the placebo.
Deficiency Symptoms of Ornithine
- Since the body can produce ornithine, a deficiency of this non-essential amino acid is rare.
- A deficiency of this nonessential amino acid is unlikely, though depletion can occur during growth or pregnancy, and after severe trauma or malnutrition.
Rich Food Sources of Ornithine
- carob, chocolate, coconut, dairy products, gelatin, meats, oats, peanuts, soybeans, walnuts, wheat, and wheat germ.