- What is glycine?
- The role of glycine in the body
- He alth benefits of glycine
- Glycine - food sources
- Glycine supplementation
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Glycine is one of the 20 protein amino acids. It is one of the endogenous amino acids, i.e. those produced by the body. Glycine forms collagen structures, is a neurotransmitter and immunomodulator. But this is not the end of its functions in the body. Why is glycine important to the body? What diseases does glycine help to prevent? Is its supplementation safe?
Glycineis one of the 20 simplest protein amino acids of all amino acids and the formula NH2-CH2-COOH. In chemical nomenclature, glycine is called aminoacetic acid.
What is glycine?
Glycine accounts for 11.5% of all amino acids in the human body. It is an endogenous amino acid, i.e. an amino acid produced by the body. The sources of glycine production are other amino acids:
- L-glutamate,
- L-alanine,
- L-threonine,
- L-hydroxyproline
- and L-serine in the presence of appropriate enzymes, as well as choline.
Glycine is a white powder with a sweet taste similar to glucose.
All biologically active amino acids are L-amino acids. What does it mean?
The letters "L" and "D" in front of the amino acid name inform about which of the optical isomers of the amino acid we are dealing with. Optical isomers have the same total composition, but differ in the position of the substituents relative to the central atom and twist the polarized light in opposite directions. This makes some of the properties of chemical compounds very different from each other.
For a compound to be optically active, it must have 4 different substituents. Glycine does not meet this condition and is the only amino acid not optically active. This means that for glycine there is no need to use the terms "L-glycine" and "D-glycine" because the distinction between these isomers is simply not found in nature.
The role of glycine in the body
Glycine creates collagen
Glycine is primarily associated with the main component of collagen. Due to its short chain and small molecule, glycine forms very compact structures, which makes it the basic component of alpha-helices (protein secondary structure), and in particular of collagen's triple helixes.
Collagen, i.e. the main structural protein of connective tissue, which binds skin and muscle cells together,bone and cartilage, about 30% is made of glycine.
Glycine needs to be produced in the body in adequate amounts for the he alth of joints, bones and skin.
Glycine is a neurotransmitter
Glycine is a neurotransmitter in the central nervous system, the main inhibitory neurotransmitter in the spinal cord. Among other things, it controls food intake and behavior.
Abnormal glycine levels can cause uninhibited muscle contractions.
The amount of glycine in the central nervous system is higher in the medulla, pons and spinal cord, and lower in the cerebral hemispheres and the cerebellum.
Glycine is essential for the production of glutathione
Glutathione is a very powerful antioxidant that the body makes from L-glutamic acid, L-cysteine, and glycine.
In the case of glycine deficiency, the body produces less glutathione, which over time increases the risk of disease and contributes to faster aging of the body.
The elderly should especially take care of the increased supply of glycine, because the level of glutathione naturally decreases with age.
Glycine is a component of creatine
Creatine is an excellent source of energy for muscles during short and intense episodes of exercise, such as weightlifting, jumping or sprinting. It is one of the most widely used supplements in sports thanks to its anabolic and anti-catabolic effects on muscles.
Creatine is synthesized by the body from L-arginine, L-methionine and glycine. Due to the production of creatine by the body, physically active people are advised to increase the consumption of amino acids, including glycine.
Other glycine functions
- bile s alt formation in liver cells,
- participation in purine biosynthesis,
- participation in porphyrin biosynthesis,
- participation in heme synthesis,
- regulation of the immune system through the synthesis of cytokines and control of the intracellular level of calcium ions,
- creating numerous proteins in the body.
How do individual body parts age?
See the gallery of 10 photos
He alth benefits of glycine
Glycine taken as a dietary supplement can have great he alth benefits. It improves tissue growth, well-being, sleep quality and cognitive performance. It is used to treat schizophrenia.
Glycine supplementation in appropriate doses may be effective:
- to treat liver damage,
- metabolic disorders in people with cardiovascular diseases,
- with various inflammatory diseases,
- obesity,
- cancer
- and diabetes.
Most studies have so far been conducted on animals, so we cannot speak of glycine therapy yet, but the results are very promising.
Taking glycine can be very helpful in:
- reversing and preventing liver damage from excessive alcohol consumption,
- protection of intestinal epithelial cells in inflammatory bowel diseases and inflammations caused by toxic and pro-oxidative factors,
- treatment and prevention of gastric ulcer,
- protection of joints against rheumatoid inflammation,
- inhibiting the proliferation of cells of certain types of cancer, as glycine blocks the synthesis of tumor-causing factors - TNFα and κB,
- reducing the damage caused by cardiac ischemia.
Based on human research, glycine is known to be effective in improving sleep quality. Taking 3 g of glycine at bedtime:
- makes it easier to fall asleep at night,
- shortens the time of falling asleep,
- prevents you from waking up at night,
- reduces daytime sleepiness
- and improves cognitive functions.
Higher levels of glycine in the body are associated with a lower risk of heart disease and heart attacks, according to an observational study of 4,100 people. The cardioprotective effect of glycine is associated with improving the lipid profile, reducing plaque accumulation and increasing the body's ability to use nitric oxide, which lowers blood pressure and improves blood flow in the vessels.
Preliminary studies suggest that glycine supplementation increases cell sensitivity to insulin in people with type 2 diabetes. In addition, higher blood glycine levels are associated with a lower risk of type 2 diabetes, even after considering other factors, including lifestyle .
This is a very interesting area that requires more research, but people at risk and with type 2 diabetes may benefit from glycine supplementation.
Glycine - food sources
Glycine is found in very high concentrations in collagen and elastin - the proteins that make up the skin, cartilage, bones, etc. You can get very large amounts of it by eating broth slowly cooked on the bones.
Another best source is meat or vegetable jelly over gelatin. In addition, glycine can be obtained from all meats, fish, dairy products and eggs. Good vegetable sources of glycine include spinach, kale, cauliflower, pumpkin, kiwi fruit, and bananas.
Glycine supplementation
Glycine in supplement form hasin the form of a sweet powder, so it is best to use it as a sweetener in desserts, cocktails, oatmeal, yoghurt, coffee or tea.
Is glycine supplementation safe?
Glycine, even in very high doses (up to 90 g per day), does not cause serious side effects. Symptoms observed with the consumption of such large amounts of glycine relate to problems with the digestive tract - nausea, stomach pains, less often vomiting and flatulence.
Dosages of glycine administered to research participants most often range between 3 and 5 g per day. When using glycine for pro-he alth purposes, it is worth including such amounts in the diet.
About the author
Aleksandra Żyłowska-Mharrab, dietician Food technologist, dietitian, educator. A graduate of Biotechnology at the Gdańsk University of Technology and Nutritional Services at the Maritime University. A supporter of simple, he althy cuisine and conscious choices in everyday nutrition. My main interests include building permanent changes in eating habits and individually composing a diet according to the body's needs. Because the same thing is not he althy for everyone! I believe that nutritional education is very important, both for children and adults. I focus my activities on spreading knowledge about nutrition, analyze new research results, and make my own conclusions. I adhere to the principle that a diet is a lifestyle, not strict adherence to meals on a sheet of paper. There is always room for delicious pleasures in he althy and conscious eating.