Tag Archives: glycine

Amino Acids and Gut Health – Glutamine and Other Aminos

There are a number of amino acids that affect the intestines and are necessary for proper functioning. Several amino acids and gut health are connected; in particular, glutamine (which I will cover more in-depth below), arginine, glutamate, glycine, threonine, lysine, as well as sulfur-containing aminos. These amino acids and gut functioning are important because they act as fuels for mucosa in the small intestine, and also for the synthesis of nitric oxide (NO), intestinal proteins, polyamines, and other products that are necessary for health. Amino acids come from protein foods like meats, fish, and eggs, or from taking supplements. 

What this means—according to a study by WW Wang, SY Quiao, and DF Li—is that glutamine and the other amino acids and gut-promoting effects from these aminos are not only “critical for the absorption of nutrients” but also are required for the “gut integrity, growth, and health in animals and humans.”

The researchers show that amino acids and gut health, in particular, indicate both trophic and cytoprotective effects. Trophic means relating to feeding and nutrition, and cytoprotective means it protects the cells from noxious chemicals and other things that would otherwise bother the intestinal tract and cause health problems.

Amino acids and gut health includes glutamine

According to the researchers RR van der Hulst, MF von Meyenfeldt, and PB Soeters, one of the essential amino acids and gut nutrients is glutamine. This non-essential amino acid (meaning your body can produce it, even though you can also get it through protein foods and supplements), is “an important nutrient for rapidly dividing cells such as cells from the immune system and the gut.”

There are a few conditions that can also cause a lack of glutamine, which can, according to the scientists, result in “functional disturbances of the immune system and/or the gut. Glutamine is produced mainly by the muscle tissue. A decrease in muscle mass during nutritional depletion may result in decreased glutamine production capacity. Furthermore during critical illness, there is an increased demand for glutamine probably as a result of an increased utilization by the immune system.”

Additionally, glutamine as one of the amino acids and gut nutritives, is important because it prevents toxins and/or bacteria from migrating from the gut lumen (the hollow part of the intestine) into the circulation of the system. Not having enough glutamine can deteriorate this barrier within the intestine and would, in this case, require supplementation of glutamine.

Lastly, glutamine (or other amino acids and gut health) may need to be supplemented in case of nutritional depletion, parenteral nutrition, or even critical illness.




Amino Acid Glycine Protects Muscles From Cancer Cachexia

Can the non-essential amino acid glycine become part of a treatment to improve quality of life for cancer patients? An animal study from Australia found some promising results.

Cachexia is a wasting syndrome, characterized by loss of weight, muscle atrophy, and loss of body mass which cannot be reversed by simply consuming more nutrition. This loss of body mass is often caused by cancer, often end-stage or advanced cancer. Cancer cachexia greatly affects quality of life, and can often hasten the patient towards their death. Cachexia is probably responsible for about 20 per cent of cancer deaths.

Cancer cachexia is caused by inflammation, the body’s complex response to harmful stimuli, such as cancer, as the body tries to destroy the cancer cells. Inflammation causes pain, and often swelling and loss of function. New treatments to reduce inflammation, which would also improve cancer therapies, are being researched globally.

D Ham, K Murphy, et al, researchers at the University of Melbourne in Australia, developed an animal trial to see if the amino acid glycine could become part of a safe, non-toxic treatment for cancer-induced muscle wastage.

Glycine is not an essential part of the human diet, as we synthetize it in our bodies from the amino acid serine. It is a neurotransmitter, but has other important effects too. It plays a role in detoxification, and could be an effective anti-inflammatory agent. It is glycine’s anti-inflammatory qualities that the researchers wanted to test.

Glycine protects muscle wastage – may be used for cachexia in cancer patients

Cachexia was induced in mice, which were then injected with glycine, alanine, or citrulline every day for 21 days. After this, selected muscles, tumors, and fat tissues were studied.

The glycine had impressive results. The mice given glycine had much less fat and muscle wastage, and less inflammation. Oxidative stress was also reduced.

The researchers concluded that glycine protected skeletal muscle from wastage and loss of function caused by cancer. They hope that in future, safe, non-toxic glycine treatments to protect against cancer cachexia will be developed.



Anti-Inflammatory Effect of Amino Acids Cysteine, Glycine and Histidine

Inflammation in the body is like fire in the veins! But can inflammation be “cooled off” by the amino acids cysteine, glycine, and histidine? Inflammation is characterized as the bodily response of vascular tissues to unsafe stimuli. 

Such stimuli may include pathogens, irritants or damaged cells. Symptoms can vary in cases of inflammation, but the most common signs are redness, heat, swelling, pain, and loss of function in the affected area.

Because inflammation is a discomfort that affects a majority of the population at one time or another, researchers at Yamaguchi University Graduate School of Medicine in Japan set out to examine the anti-inflammatory effects of the amino acids cysteine, glycine and histidine.

Researchers S. Hasegawa, et al., report that nuclear factor-kappa B is a system that regulates endothelial activation. They explain that nuclear factor-kappa B is induced by tumor necrosis factor-alpha in vascular endothelial cells, and it is this process that can lead to inflammation and disorders such as atherosclerosis.

The researchers wanted to test the anti-inflammatory effects in coronary endothelial cells since results from previous studies ended inconclusively. They hypothesize that amino acids cysteine, glycine and histidine would produce inhibitory effects on nuclear factor-kappa B activation in human coronary arterial endothelial cells.

The effect of amino acids cysteine, glycine and histidine on inflammation in endothelial cells

For the study Hasegawa et al. took human coronary arterial endothelial cell cultures and treated them with either alanine, cysteine, glycine and histidine amino acids. They stimulated the cultures with 2 ng/mL of tumour necrosis factor-alpha before taking out nuclear extracts to determine their concentrations of proteins and nuclear factor-kappa B.

They found that without treatment, the cultures showed significant activation of nuclear factor-kappa B. But with pretreatment of cysteine, glycine and histidine, nuclear factor-kappa B activation was inhibited significantly in the coronary endothelial cells. Alanine did not have an effect on the activation, demonstrating no anti-inflammatory properties.

Overall, cysteine showed the most inhibiting effects out of the tested amino acids at any concentration. They also found that the amino acids inhibited E-selectin expression, a cell adhesion molecule that plays an important role in inflammation.

Based on these results, the researchers conclude that cysteine, glycine and histidine can help reduce inflammation to the endothelial cells.



The Importance of GABA Amino Acid for the Central Nervous System

The human central nervous system is controlled by the brain. The brain’s neurotransmitters and receptor sites are affected either by how inhibited or excited the amino acids GABA (gamma-aminobutyric acid) and glutamate (glutamic acid) are. Of all the neurotransmitters within the central nervous system, amino acids are considered some of the most plenteous.

Steven M Paul write about “GABA and Glycine” and their role in the central nervous system. Amino acids have been shown in studies, he says, to “support current dogma that the majority of neurons in the mammalian brain utilize either glutamate or g-aminobutyric acid (GABA) as their primary neurotransmitters. [And] … GABA and glutamate serve to regulate the excitability of virtually all neurons in brain and, not surprisingly, therefore have been implicated as important mediators of many critical physiological as well as pathophysiological events that underlie brain function and/or dysfunction.”

There are studies in pharmacology on utilizing drugs that either block or enhance what GABA or glutamate, which according to Steven M Paul, supports that these neurotransmitters “by virtue of their often opposing excitatory and inhibitory actions, control, to a large degree, the overall excitability” of the central nervous system.

What this means, is that drugs (such as for schizophrenia, neurological diseases, or Lou Gehrig’s disease) that inhibit what GABA does may decrease what glutamate may excite, or vice versa. This means there needs to be a balance between inhibition and excitation in the “drugs which are known to alter GABAergic or glutamatergic neurotransmission).”

GABA amino acid is important to the central nervous system and spinal column

In a study done by J Yowtak, J Wang, et al., at the Department of Neuroscience and Cell Biology at the University of Texas, the neuropathic pain model in mice was studied regarding the antioxidant treatment on GABA neurons in the spinal column. The researchers suggested “that oxidative stress impaired some spinal GABA neuron activity in the neuropathic pain condition. Together the data suggest that neuropathic pain, at least partially, is attributed to oxidative stress which induces both a GABA neuron loss and dysfunction of surviving GABA neurons.”

Between the study above and the one spoken of by Steven M Paul, it is likely that all of the updated information on GABA, glutamate, or glycine will hopefully, as Paul states, “result in an even better understanding of their potential role(s) in various neuropsychiatric disorders and in the discovery even more of effective therapeutic agents.”

Certainly our central nervous system is dependent upon GABA and these other amino acids. It is no wonder that they are used in pharmaceutical drugs to enhance and inhibit certain neurotransmitters to help the body function properly.




Table of Amino Acid Abbreviations

Students and teachers come together with terms like “Amino acid abbreviations” – but scientists use these abbreviated forms to refer to the 20+ names of amino acids as well.

Amino acids are the building blocks of proteins, and they can be gotten from food. Before we get into the amino acid abbreviations you may want to know that there are two main types of amino acids (with a few exceptions)…

Essential and Non-essential amino acids

Essential amino acids does not mean they are “essential” as in necessary… it simply means that they can only be gotten from the food you eat so must be included through diet or dietary supplementation. Protein foods like meats (beef, chicken, pork, etc.) and eggs, as well as fish, are excellent sources of amino acids. Many meat-eating Americans actually eat an overabundance of protein compared with what the human body requires, which can lead to acidity (which leads to disease), cardiovascular and other diseases.

Non-essential amino acids are those that your body can produce naturally. Occasionally, someone is born with a deficiency in their body’s ability to produce the amino acids necessary for proper functioning, leading to diseases or disorders where people have trouble breaking down certain amino acids. An example of the latter is Maple Syrup Urine Disorder (MSUD) which is what newborn babies are screened for soon after birth.

There are 22 different amino acids in all (some of them semi-essential), but about 20 of them are more common. Their names, 3-letter, and 1-letter amino acid abbreviations follow.

Table of amino acid abbreviations

Amino Acid












Aspartic acid






Glutamic acid













































Aspartic acid or Asparagine



Any amino acid



Termination codon


For more information on amino acid abbreviations or more detailed information on amino acids in general, please see other articles at the Amino Acid Information Center. There are also many excellent resources on the Internet or in encyclopedias.





Selenium and Selenocysteine and Health

Selenium is a nonmetal element on the periodic table (between sulfur and tellurium), while Cysteine is a semi-essential amino acid. But when Selenium performs its biological functions, it does so through selenoproteins. Selenoproteins have selenium in them as the form of the 21st amino acid, selenocysteine (also called Sec), which is a cysteine analog. Selenocysteine is encoded by the UGA codon (one of three) in mRNA translation for non-selenoprotein genes. Selenocysteine is a proteinogenic amino acid.

Unlike the 20 regular amino acids (both essential and non-essential) selenocysteine is biosynthesized on its tRNA from the amino acid serine. Interestingly, there are 25 selenoproteins, like selenocysteine and selenomethionine (the latter of which replaces methionine amino acid residues, and is sometimes randomly substituted for methionine), which are encoded in our human genome.

Study on selenium and selenocysteine on health

Selenocysteine, according to S Kurokawa and MJ Berry, in their publication titled Selenium. Role of the essential metalloid in health discuss selenocysteine and its role in health. They say that selenocysteine (Sec) is described as “having stronger nucleophilic and electrophilic properties than cysteine, and Sec is present in the catalytic site of all selenoenzymes. Most selenoproteins, whose functions are known, are involved in redox systems and signaling pathways. However, several selenoproteins are not well characterized in terms of their function.”

Even though selenium can be considered toxic if the dose is too high, it is still required for health purposes in the bigger picture, selenocysteine notwithstanding. According to the researchers the selenium field (which includes the selenoproteins, and selenomethionine, etc.) has “grown dramatically in the last few decades, and research on selenium biology is providing extensive new information regarding its importance for human health.”

Selenocysteine, itself, is a building block of selenoproteins, contains selenium, and is present in several enzymes such as glutathione peroxidases, glycine reductases, methionine-R-sulfoxide reductase B1 (SEPX1), and so on). Glutathione and glycine are standard amino acids.

The biochemist, Theresa Stadtman (married to Earl R. Stadtman) at the National Institutes of Health, discovered selenocysteine.



Glycine Amino Acid May Help Control Schizophrenia

Could glycine amino acid help people with mental health disorders such as schizophrenia?

Schizophrenia is a mental disorder where someone suffers from the inability to tell the difference between what is real and what is not (delusional thoughts). The symptoms of schizophrenia can include hallucinations, paranoia, delusions, disorganized speech and thinking. These symptoms of this mental health problem disrupt work and social life.

A recent study was conducted at Harvard Medical School to determine if oral intake of glycine amino acids contributed to the treatment of schizophrenia. Previous studies showed that subjects who consumed glycine for two weeks showed signs of improvement.

Glycine is an amino acid, a natural compound that is produced by the consumption of protein in your diet. The amount of it in your diet is, however, very small.

For this specific study, the researchers at Harvard Medical School monitored oral glycine intake in 11 healthy adult men. The glycine intake in these subjects was monitored by using a non-invasive proton magnetic resonance spectroscopy technique to measure brain glycine changes.

The results showed a 38% increase in brain glycine ratio. The purpose of this study was to further understand the glycine dynamics in the human brain. Therefore, the findings are significant to future treatments of schizophrenia and other glutamate system dysfunctions.

The glutamate system is made up of neurotransmitters in the nervous system and glutamate receptors found throughout the brain and spinal cords. The glutamate system plays a huge role in normal physiological functions.

The results of this study suggest that people with schizophrenia and people with other physiological dysfunctions can benefit from oral glycine intake to help them control the mental disorder.

In other words, by taking glycine orally as a glycine dietary supplement, you may be able to control the symptoms of schizophrenia and other mental disorders.

To read further about the study, visit http://www.ncbi.nlm.nih.gov/pubmed?term=Oral%20glycine%20administration%20increases%20brain%20glycine%2Fcreatine%

Glycine Metabolism: Cancer Targeting Treatment?

Are we now able to peek into dangerous areas, like cancer, that would normally kill us? Scientists are having a look at glycine metabolism and its role in cancer growth. Researchers in Boston investigated the mutations cells undergo when healthy cells are mutated into cancer cells, and looked into possible ways of targeting these cancer cells.

Cancer occurs when previously healthy cells mutate, proliferating—replicating–rapidly. In fact, the definition of cancer is a malignant neoplasm, which refers to a group of diseases involving unregulated cell growth. The cancer cells divide and grow uncontrollably, forming malignant tumors which are often fatal. Rapidly proliferating cancer cells can spread to other parts of the body through the bloodstream or lymphatic system.

Very simply put, cancer can spread so rapidly because cancer cells reprogram normal, healthy cells. Mohit Jain, Roland Nilsson, et al, researchers with Harvard Medical School, Boston, USA, wanted to examine this metabolic reprogramming of cancer cells.

They studied 60 well-characterized human cancer cell lines, from nine common tumor types, to characterize cancer cell metabolism. The researchers profiled the cellular consumption and release of over 200 metabolites, the molecules which are necessary for metabolism.

Link between glycine metabolism and cancer cells

In the in vitro experiment, cancer cell lines were cultured, and their metabolites were measured. The researchers found a significant correlation between glycine consumption and cancer cell proliferation.

Glycine is a non-essential amino acid, which can be synthesized by our bodies. In the study, glycine was consumed by rapidly proliferating cells, and released by slowly proliferating cells. This means that glycine is demanded by the cancer cells. The glycine consumption was pronounced in ovarian, colon, and melanoma tumor cells.

The researchers discovered that the glycine biosynthetic pathway was closely linked to cancer cell proliferation, meaning that the cancer was relying on glycine to spread. This increased reliance could make the cancer cells metabolically vulnerable to specific targeting.

The study concluded that this metabolism of glycine could be used to target the rapidly proliferating cancer cells, possibly becoming a new anti-cancer treatment.



Glycine Benefits: Glycine for Cancer, Diseases, and Other Health Benefits

Glycine is an amino acid that has amazing implications for human health and nutrition. Through the kidneys and liver, glycine uses inter-organ metabolism where it is synthesized from threonine, serine, hydroxyproline, and choline. Glycine is used by the bodies of both humans and animals.

A study done by W Wang, Z Wu, et al., at the State Key Laboratory of Animal Nutrition in Beijing, China’s Agricultural University, covered some of the glycine pathways and how it is biosynthesized and what it is good for.

Benefits of Glycine

According to the study in Beijing, glycine degrades through three different pathways in the body: through glycine cleavage system (GCS), serine hydroxymethyltransferase, and also conversion. Also, “glycine is utilized for the biosynthesis of glutathione, heme, creatine, nucleic acids, and uric acid.”

What many don’t know is that glycine is an important part of bile acids from the liver, which are secreted into the small intestine for the breakdown of fats in digestion. The glycine then, via the bile acids, also help absorb long-chain fatty acids.

According to those who did the study, glycine “plays an important role in metabolic regulation, anti-oxidative reactions, and neurological function.

Thus, this nutrient has been used to:

(1) prevent tissue injury
(2) enhance anti-oxidative capacity
(3) promote protein synthesis and wound healing
(4) improve immunity, and
(5) treat metabolic disorders in obesity, diabetes, cardiovascular disease, ischemia-reperfusion injuries, cancers, and various inflammatory diseases.”

Glycine Benefits Reviewed

The uses for glycine in the body are unreal! Glycine is obviously beneficial to human health, and it is seriously a functional amino acid.



L-Glycine for Sleep

The next time you’re feeling the effects of sleep deprivation, consider adding L-glycine to your diet. A non-essential amino acid found predominantly in proteins, L-glycine is created in the body from another amino acid, serine. L-glycine has a variety of functions, such as protein production and as an inhibitory neurotransmitter in the spinal cord and brain. 

It is because of the amino acid’s inhibitory function that researchers at the Institute for Innovation and University of Miyazaki in Japan wanted to study the effects of L-glycine on insomnia symptoms by improving sleep quality. Researchers Makoto Bannai, Nobuhiro Kawai, Kaori Ono, Keiko Nakahara and Noboru Murakami report that insomnia affects about 30 per cent of the population.

Symptoms can include sleepiness, fatigue, inability to focus, memory deficits, and irritability, so finding an efficient treatment for insomnia is vital.

For the experiment, 10 healthy participants were recruited and baseline measures of sleeping patterns were recorded. In the randomized, crossover trial, the participants were given either three grams of L-glycine or a placebo half an hour before bedtime. Their sleep time was restricted to an average of 5.5 hours for three nights in a row. Their insomnia symptoms were evaluated using a visual analog scale, questionnaires, and various performance tests.

L-Glycine Effects on Sleep Quality

Researchers Bannai, Kawai, Ono, Nakahara and Murakami found that reaction time was significantly reduced for the L-glycine group when doing the psychomotor vigilance test. The amino acid group also tended to do better for the other forms of performance tests.

Self-reported symptoms of insomnia were improved only for the first day of sleep deprivation for the L-glycine group, but objective measures were improved up to the third day. The researchers also found that when compared to the placebo, the L-glycine participants had significantly less feelings of fatigue and improved sleep quality.

Based on findings from rat experiments, the researchers believe that the improvement in sleep quality stems from L-glycine’s ability to lower the body’s core temperature, which occurs naturally during sleep.