Once eaten and digested, dietary protein is broken down into individual amino acids, which are then absorbed into the blood stream and transported around the body. Amino acids are small molecules that combine to make the various proteins that the cells in the body need. Twenty different naturally occurring amino acids are required by the body for these processes, consisting of non-essential amino acids which the body produces, and essential amino acids that must come from food.
Glycine is one of these 20 individual amino acids that the body needs to function properly, and these amino acids combine in different ways to make proteins, the building blocks of the body. The basic structure of a single protein is a chain of individual amino acids, linked together in a special way, referred to as a unique sequence. The thousands of different proteins in the body have different functions.
Although glycine is a lesser-known amino acid, it plays such an important role in the body that it deserves to be highlighted.
What is glycine?
Glycine is a simple, non-essential amino acid vital to human health, as the body requires glycine for many biochemical processes. It is the smallest amino acid and forms an integral component of many biological molecules and metabolic reactions. Also known as amino acetic acid, glycine is an important component of many proteins made in the body. Its name comes from the Greek word “glykys”, which means sweet. It appears as a colourless crystalline with a sweet taste and is highly soluble in water.
Glycine is made in the body from precursors such as choline, serine, glyoxylate, and threonine. When the body produces less glycine than it requires, the shortfall would have to come from dietary sources or supplements.
Potential benefits and effects of glycine:
Glycine is a versatile amino acid with many potential health benefits, as many processes in the body, such as cell signaling, require glycine. It also acts as a precursor to make various other biomolecules, such as creatine.
- Making glutathione: Glycine is a precursor (along with cysteine and glutamic acid) to making glutathione, the most powerful antioxidant in the body, which helps to improve immune system function. Glutathione fights inflammation and saves cells from oxidative stress and damage from free radicals. Studies have shown that a lack of glycine can lower glutathione levels.
- Increasing creatine production: Glycine is one of the amino acids that helps to produce creatine, which is a compound that provides energy to the muscles, supports muscle growth and power, and may improve bone health and brain function.
- Making collagen: Glycine is essential to make collagen, as a major part of collagen is made up of glycine. Collagen has been described as the glue holding the body together, as its fiber-like structure is used to make connective tissue, connecting tissue with other tissue. It is a major component of bone, cartilage, skin, tendons, and muscle in the body.
- Improve sleep quality: Studies have shown that supplementation with glycine can improve sleep quality. It helps to activate the N-methyl-D-aspartate receptor in the brain, which may have a calming effect on the brain and lower core body temperature to help improve symptoms of sleep disorders.
- Protect the liver from alcohol damage: Animal studies have shown that glycine lowered the amount of alcohol in the blood by boosting the speed at which the stomach can break down alcohol, which may help to prevent alcohol from damaging the liver.
- Reducing the risk of muscle loss: Animal studies have shown that glycine might stop the loss of muscles, such as when getting older, and boost muscle growth.
- Assists with managing type 2 diabetes: Glycine is suggested to help improve insulin response in people with type 2 diabetes, but more research is needed to corroborate it.
- Assisting with inflammation: Preliminary studies in cell cultures in laboratories and animal studies suggest that glycine may exert an anti-inflammatory effect by downregulating pro-inflammatory pathways in the body. Glycine has been proposed to help treat conditions with low-grade inflammation, such as obesity, but corroborative studies in humans are still lacking.
- Neurotransmitter: Glycine acts as a neurotransmitter in the central nervous system.
- Gastrointestinal disorders: Glycine shows promise in treating gastrointestinal disorders and may protect against inflammation and gastric ulcers.
- Immune function: Glycine supports the immune function by regulating cytokine synthesis. Cytokines are signaling proteins that help control inflammation in the body.
Sources of glycine:
As glycine is an amino acid, which is found in dietary proteins, adequate protein intake would naturally boost glycine levels. The highest concentrations of glycine are found in collagen-rich animal protein, such as in the bone, skin, and connective tissue, as well as in tougher cuts of meat that require slow cooking, such as shoulder roasts, brisket, and chuck. Sources of animal protein include meat, poultry, seafood, eggs, and dairy products,
Soybeans are deemed to be the plant food with the highest levels of glycine, while other good plant sources include other legumes, nuts, and seeds.
The body naturally produces glycine, being synthesized from other amino acids, making it more realistic to prioritize protein in general, rather than seeking out foods that are specifically high in glycine.
Glycine supplements are available as capsules and powders. There is no standard dose for glycine supplements, but most studies stick to doses of 3-5 grams daily.
Conclusion:
Glycine has been described as an all-purpose amino acid with many possible health benefits and constitutes about 11% of the amino acid content in the body. As a vital compound of important items such as antioxidants, creatine, and collagen, glycine affects various aspects of our health, such as sleep, liver function, heart health, diabetes control, nervous system functioning, and looking after the muscles. Symptoms of deficiency may include fatigue, muscle weakness, digestive issues, and cognitive impairment.
References:
Health benefits of glycine. Published 29 November 2022. WebMD. (www.webmd.com)
Health benefits of glycine. Published 10 June 2024. Health. (www.health.com)
Top 9 benefits and uses of glycine. Published online. MedicineNet. (www.medicinenet.com)
Glycine: The smallest anti-inflammatory nutrient. Published 8 July 2023. International Journal of Molecular Sciences. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
Glycine. Published online and updated 5 June 2023. Examine. (Claimed to be the largest database of nutrition and supplement research on the Internet.) (www.examine.com)
Recent developments in glycine transporter-1 inhibitors. Published in Annual Reports in Medicinal Chemistry, 2010. Science Direct. (www.sciencedirect.com)
Glycine structure. Published online. BYJUS. (www.byjus.com)
What is glycine and is it good for you? Published 6 March 2024. Levels Health. (www.levelshealth.com)
Glycine benefits: Exploring the science-backed advantages. Published online and updated 4 July 2024. PharmEasy. (www.pharmeasy.in)
Glycine. Published online. Rupa Health. (www.rupahealth.com)
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