Glycine, a non-essential amino acid , is a fundamental component of proteins. Known for its multiple biological roles, it is particularly prized by athletes for its many benefits.
Here we will explore the benefits of glycine to enhance physical performance and support recovery.
What is glycine?
Definition and history
Glycine, also called aminoacetic acid, is one of the 22 proteinogenic amino acids, essential for the formation of proteins in the body.
It was first isolated by French chemist Henri Braconnot in 1820. Glycine gets its name from the Greek "glykys", meaning "sweet", because of its sweet taste. Today, it is produced industrially from chloroacetic acid and ammonia.
Unique Features
Unlike most other amino acids, glycine is nonchiral, meaning it does not have an asymmetric carbon. This distinguishes it and simplifies its notation, without the "L-" prefix commonly used for other amino acids.
Biological functions of glycine
Collagen synthesis
Glycine is fundamental for the synthesis of collagen , the most abundant protein in the human body. Collagen is essential for maintaining the structure and strength of bones, cartilage, tendons and ligaments.
By stimulating the production of collagen , glycine contributes to the regeneration of connective tissues and joint health, which is particularly beneficial for athletes subjected to intense physical effort.
Bile acid metabolism
Glycine is involved in the formation of bile acids, which are necessary for the digestion and absorption of fats.
By combining with bile salts, it helps make these compounds more soluble, thus facilitating their excretion and participating in the detoxification of the liver, making it an excellent liver food supplement .
Precursor of bioactive compounds
Glycine is an important precursor to several biologically active compounds, including creatine, porphyrins, glutathione, acetylcholine, and uric acid.
Each of these compounds participates in important metabolic processes, from oxygen transport to antioxidant protection to nerve and muscle function.
Regulation of homocysteine metabolism
One of the notable benefits of glycine is its ability to regulate homocysteine levels in the blood. Homocysteine, an amino acid derived from methionine, can be harmful in high concentrations.
Glycine helps reduce homocysteine levels, maintaining your cardiovascular fitness and acting to prevent complications related to overconsumption of animal proteins.
The benefits of glycine for athletes
Muscle development and recovery
Glycine is widely recognized for its positive effects on muscle mass . By promoting protein synthesis and increasing the secretion of growth hormone , it helps build muscle. After exercise, glycine helps rebuild muscle fibers, thus speeding up recovery and reducing muscle fatigue.
Joint protection
As a component of collagen, glycine plays an important role in protecting joints. As a joint supplement , it helps maintain the integrity of tendons and ligaments, reducing the risk of injuries related to intense physical activity.
Athletes benefit from improved joint resilience and faster recovery after training.
Improved sleep quality
Studies have shown that taking glycine before bed improves sleep quality . By acting as an inhibitory neurotransmitter, it helps regulate nerve impulses, promoting restful sleep.
Good sleep is essential for physical recovery and improving your athletic performance.
Antioxidant effects
Glycine participates in the synthesis of glutathione , an extremely powerful and important antioxidant for the body.
Glutathione protects cells from oxidative damage, reducing inflammation and oxidative stress caused by intense exercise. This contributes to the recovery and overall health of athletes.
Food sources of glycine
Glycine, as a nonessential amino acid , is present in many foods, mainly those rich in protein.
These natural sources make it possible to incorporate this vital amino acid into your daily diet, providing various benefits for health and physical performance.
Meat and poultry
Meats and poultry are among the best sources of glycine. Beef, chicken and pork contain significant amounts of this amino acid, due to their richness in collagen proteins.
- Beef: Beef is a major source of glycine, especially cuts rich in connective tissue such as shank and marrow bones. These parts are often used to make collagen-rich broths.
- Chicken: Glycine is abundant in chicken, especially in the skin and cartilaginous parts. Chicken broth, prepared with bones and skin, is an excellent source of glycine.
- Pork: Like beef and chicken, pork contains glycine, particularly in cuts like pig's feet and bones used for broths.
Pisces
Fish, especially oily fish, are also good sources of glycine. Fish contain collagen proteins that provide this amino acid.
- Salmon: Salmon is not only rich in omega-3, but also in glycine, which contributes to muscle and joint health.
- Tuna: Tuna, especially canned, is a convenient source of glycine.
- Other oily fish: Fish such as mackerel and trout also provide notable amounts of glycine.
Dairy products
Dairy products, although less rich in glycine compared to meats, nevertheless contribute to the overall intake of this amino acid.
- Milk: Both whole milk and skim milk contain glycine, although the concentrations are moderate.
- Yogurt: Yogurt, especially Greek yogurt, is a source of glycine due to its high protein content.
- Cheese: Cheeses like cheddar, parmesan, and mozzarella also provide glycine.
Legumes
Legumes are an excellent source of plant-based protein and glycine, ideal for those following a vegetarian or vegan diet.
- Peas: Green peas and split peas are rich in glycine.
- Lentils: Lentils, whether green, red or brown, provide a good amount of glycine.
- Beans: Red, black and white beans are also important sources of this amino acid.
Cereals
Whole grains, such as wheat and corn, contain glycine, although their levels are generally lower than those in meats and fish.
- Wheat: Whole wheat and its derivatives, such as whole wheat bread and pasta, contribute to glycine intake.
- Corn: Corn, in grain or flour form, is another source of glycine.
Vegetables
Some vegetables, although not as rich in glycine as animal sources, nevertheless offer notable amounts of this amino acid.
- Spinach: Spinach is a plant-based source of glycine and other beneficial nutrients.
- Cabbage: Green cabbage and kale contain glycine.
- Parsley: Parsley, often used as a garnish, is also a source of glycine.
Glycine Supplements
To maximize the benefits of glycine , especially for athletes looking to improve their performance and recovery, taking glycine in the form of a health food supplement is an effective alternative.
These supplements provide concentrated doses of glycine without the added calories of protein-rich foods. The supplements are available in powder or capsule form, giving you flexibility when it comes to choosing how to consume them.
Dosage and use
Recommended dosage
Glycine dosage depends on individual goals. For athletes, a dose of 5 to 10 grams per day is generally recommended, divided into several doses throughout the day, especially before and after exercise.
For people looking to improve their sleep, a dose of 3 grams of glycine before bed is typically prescribed.
Practical use
Glycine is available in powder or capsule form. It can be taken with water or mixed into a protein drink. It is recommended to consume it with meals to promote absorption.
To maximize its effects, it is advisable to combine it with B vitamins, which facilitate its assimilation.
Glycine is an amino acid with multiple benefits, particularly appreciated by athletes for its effects on muscle growth , recovery and joint protection.
By incorporating glycine into your diet or in supplement form, you can improve your performance and overall well-being. As with any supplement, it is essential to follow dosage recommendations and consult a healthcare professional before starting a new supplement.
Sources:
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- I nagawa, K., et al. “Subjective effects of glycine ingestion before bedtime on sleep quality.” Sleep and Biological Rhythms, 2006.: https://www.researchgate.net/publication/230167843_Glycine_ingestion_improves_subjective_sleep_quality_in_human_volunteers_correlating_with_polysomnographic_changes
- Fukada, S., Shimada, Y., Morita, T., Sugiyama, K. "Suppression of methionine-induced hyperhomocysteinemia by glycine and serine in rats." Biosci Biotechnol Biochem, 2006 .: https://pubmed.ncbi.nlm.nih.gov/17031061/
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- Li, C., et al. “Regulation of glucagon secretion in normal and diabetic human islets by γ-hydroxybutyrate and glycine.” J Biol Chem, 2013 .: https://pubmed.ncbi.nlm.nih.gov/23266825/
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