You gotta get glycine (warning: science lesson ahead)

Glycine, an amino acid, is absolutely essential to life and health; and lucky for you, it's readily available in bone broth.

​What's it good for? Keep reading. 

Cellular Maintenance and Repair

Cytoprotection, detoxification and immune response are unique processes, yet they are deeply intertwined. Let’s begin with glycine’s role in methylation, an essential process that controls the synthesis of cells and regulates gene expression. As a result, it is critical for the maintenance and repair of existing tissue, building new tissue, and cellular communication. For these processes to work properly we need a balance between B vitamins (fruits, veggies, nuts seafood, liver), methionine, and glycine. Methionine comes primarily from muscle meats (steak, chicken breast, etc.), and too much of it without B vitamins and glycine will result in a large buildup of homocysteine which is toxic and has been proven to lead to cardiovascular disease (1). If you are able to get your B vitamins and methionine but are lacking glycine, then you will over-methylate and severely deplete your glycine stores, resulting in massive breakdown of cellular communication. But when you get your necessary supply of B vitamins, methionine, and glycine you are able to methylate properly so cells can communicate and create glutathione which is considered the MASTER antioxidant of the body. This is essential as glutathione is vital to protect against cell damage, meaning you feel better!
 
In addition to proper methylation, glycine has been shown to be a strong anti-inflammatory (2). Glycine helps to regulate immune function and the production of superoxide, and synthesis of cytokines by altering the intracellular Ca2+ levels, which have been proven to protect against chronic inflammation. Glycine also works to decrease inflammation by hyperpolarizing immune cells via “glycine-gated chloride channels,” preventing an exaggerated, harmful immune response to endotoxin and other stimuli. Research studies on animals have proven that glycine can protect against harmful endotoxins created from over consumption of both sugar and alcohol; they first induced fatty liver and metabolic syndrome, and subsequently reversed the conditions via glycine administration (4). There are over 200 studies concerning the protective, restorative and anti-inflammatory nature of glycine, however this is beyond the scope of the quick start. It is safe to say that glycine is a simple-yet-powerful tool to help reduce inflammation, improve detoxification, and boost the immune system.

Gut Health

​As discussed above glycine helps to decrease inflammation, which is essential to gut health. In fact, many of the gut health protocols are based on the elimination of sugars, alcohol, allergenic foods, rancid or unstable fats, and processed food. Given glycine’s anti-inflammatory potential, it already plays a key role in healing the gut - but there’s more to it. American researcher Francis Pottenger studied the importance of gelatin found in broth is a hydrophilic colloid, which attracts and holds liquids, thus facilitating digestion by attracting digestive juices to food in the gut. Glycine is the main component of gelatin, along with proline. Similarly, Carl Voit found that gelatin improved digestion because of its ability to improve hydrochloric acid balance, due to its ability to improve the flow of gastric juices, thus promoting digestion (5). Studies on gelatin have also found that it can heal the gastrointestinal (GI) tract by enhancing the mucous membrane of the intestines and is thus used extensively in healing leaky gut. 

General Tissue Health

A good indicator of the importance of glycine in tissue repair, maintenance and building can be seen with studies on pregnant women and children. These two groups need significant amounts of glycine in the diet. Research shows that glycine deficiency could limit growth in infants, and stated that the “demands of the growing fetus for glycine are very high, in both absolute terms and relative to other amino acids, two to ten times as great on a molar basis.” Thus, by increasing the intake of this glycine could improve, the outcome of preterm infants (6). In fact, studies have shown that glycine status is an important marker of normal pregnancy (7). In addition, glycine has been shown to be a limiting amino acid in children recovering from malnutrition, and it is the limiting amino acid for rapid growth (8).

References

1. Stipanuk MH. Homocysteine, Cysteine, and Taurine. In Modern Nutrition in Health and Disease(eds M.E. Shills, et al.) 545-562 (Lippincott Williams & Wilkins, 2006).
2. Zhong Z1, et al. L-Glycine: a novel antiinflammatory, immunomodulatory, and cytoprotective agent. Curr Opin Clin Nutr Metab Care. 2003 Mar;6(2):229-40.
3. El Hafidi M, Pérez I, et al. Glycine intake decreases plasma free fatty acids, adipose cell size, and blood pressure in sucrose-fed rats. Am J Physiol Regul Integr Comp Physiol. 2004 Dec;287(6):R1387-93. Epub 2004 Aug 26.
4. Senthilkumar R, et al. Protective effect of glycine supplementation on the levels of lipid peroxidation and antioxidant enzymes in the erythrocyte of rats with alcohol-induced liver injury. Cell Biochem Funct. 2004 Mar-Apr;22(2):123-8.
5. Gotthoffer, NR, Gelatin in Nutrition and Medicine (Graylake IL, Grayslake Gelatin Company, 1945), pp. 65-68.
6. Jackson, et al. Optmising amino acid and protein supply and utilization in the newborn, Proceedings of the Nutrition Society, 1989, 48, 293-301.
7. Persaud, C et al. The excretion of 5-oxyproline in urine, as an index of glycine status during normal pregnancy, British Journal of Obstetrics and Gynaecology, 1989, 96, 440-444.
8. Persaud, C et al. Glycine: limiting amino acid for rapid growth, Proceedings of Nutritional Society, 1987, 46, 236A.