Traditional bone broth in modern health and disease

Townsend Letter for Doctors and Patients, Feb-March, 2005 by Allison Siebecker

Glycine is classified as a nonessential amino acid because we can synthesize it within our body. Not all scientists believe it is unnecessary to consume it though. In fact, Yu and associates found that glycine metabolism is directly responsive to dietary glycine and that prolonged abstinence in the diet may limit the formation of heme, glutathione, purines and creatine. (37) Jackson has concluded that a marginal state of glycine is more common then previously thought. (38) Jackson also found that certain conditions increase our need for glycine, such as sickle cell anemia and pregnancy. In the case of sickle cell anemia, the high rate of heme destruction increases the requirement for glycine. (39) In pregnancy, the growing fetus creates a demand for glycine that is two to ten times greater than normal, and two to ten times greater than the need for other amino acids. (40)

Additional studies have reported positive results with glycine for health conditions. Fogarty states that glycine is "associated with a strongly reduced risk of asthma." (41) Wald demonstrated that glycine stimulates gastric acid secretion. (42) In a study on wound healing, Minuskin theorized that glycine was particularly helpful due to its high concentration in connective tissue and also due to the increased need for creatine in wound healing. (43) It has also been found to be the rate limiting step in rapid growth, of which both wound healing and fetus growth are an example. (44) Lastly, Ottenberg stated that "the ability of the liver to perform protective synthesis is limited by the amount of glycine available," and further recommended gelatin as a glycine supplement for patients with jaundice and other liver problems. (45)

Broths are often used in modified fasting and cleansing regimes. In the fasting state, glycine is used for gluconeogenesis. During periods of fasting when no food or energy source is being consumed, our body breaks down our own protein tissues, such as muscle, to create energy from. If broth is consumed, it supplies an outside source of glycine, which limits or prevents degeneration during the fast. Since glycine is also used for phase I and II detoxification, it puts broth into the category of a liver tonic (or liver supportive). Broth helps the body to detoxify during a cleanse, and in fact at any time it is eaten.

To summarize, glycine (broth) can be considered for use in the following conditions: anemia, fatigue, detoxification, blood sugar dysregulation, muscle wasting, wound healing, pregnancy, infant and childhood growth, asthma, hypochlorhydria, jaundice and liver support.

Proline

Proline is found in most of the proteins in the body. One of its main roles is in the structure of collagen. It is therefore incorporated into connective tissues such as bone, skin, ligaments and tendons, and cartilage. Proline is also considered a nonessential amino acid, but as with glycine, it may be considered 'conditionally essential' in that it is important to consume proline dietarily. Research shows that proline levels drop significantly when it is absent from the diet. (46)