From ancient to modern times and across cultures, healers have used the nourishing and medicinal powers of broth, especially bone broth. A homemade, long-simmered bone broth benefits the sick and weak, as well as for anyone suffering from an ailment involving the connective tissues—including the digestive system, joints, skin, and blood. Naturopathic doctors, Traditional Chinese Medicine practitioners, and those in the traditional foods movement consider long-simmered bone broths to be a classic example of “food as medicine.”
Bones are mineral storehouses: They are made up of 65% minerals and contain 99% of the body's calcium and 85% of its phosphorus. They also contain concentrated amounts of other important minerals like magnesium and zinc. Bones also contain collagen and glycosaminoglycans—substances found in no other foods. Bones are about 35% collagen (gelatin), a protein that makes the broth gel when it is cooled. Collagen is also found in cartilage, tendons, and skin and is what allows these tissues, as well as bones, to be flexible.
Gelatin and other forms of collagen are marketed as popular supplements for joints and other connective tissues like hair, skin, and nails, and there is some evidence in the scientific literature supporting these claims.[1,2] Most of the research has been conducted not with bone broths, but with gelatin itself and other forms of collagen for treating the most common cause of joint pain, osteoarthritis. There is good evidence from clinical studies that regular gelatin consumption improves joint pain in people with osteoarthritis. Because of its very high gelatin content, it is generally assumed that bone broth benefits joint pain as well.
Because of their incredibly high gelatin content, bone broths have also been used traditionally as natural therapy for digestive ailments, as a way to coat and soothe the gastrointestinal lining and improve digestion. Historically, it was studied as a way to improve milk and protein digestion and treat indigestion. More recently, studies have shown that that glycine, (one of gelatin’s main ingredients) stimulates hydrochloric acid secretion in the stomach and that gelatin protects the gastrointestinal mucosa from damage.[4,5]
In addition, bone broth benefits leaky gut syndrome, according to a number of modern integrative physicians who specialize in treating this common condition. Leaky gut, the condition in which intestinal permeability is abnormally increased, is now considered an underlying cause of many chronic diseases, including autoimmune disease. Because of its ability to heal leaky gut, well known integrative physician and author of the bestseller Clean, Alejandro Junger, MD, calls grass-fed beef bone broth “one of the most digestively healing, nourishing and building foods available.”
Bone broth also contains two very important glycosaminoglycans, chondroitin sulfate and hyaluronic acid, also important for the health of connective tissues like joints and skin. These compounds are found mostly in cartilage and are used by the body as lubricants and shock absorbers. Cartilage extracts containing these two compounds have been found in clinical studies to improve osteoarthritis-related symptoms and to counteract natural photo aging processes to reduce visible aging signs in the human face.[2,8] Bone broths can be an excellent source of chondroitin sulfate and hyaluronic acid, especially when they are made with high-cartilage-containing bones, such as knuckles or chicken feet.
When making bone broth, two factors appear to help the bones release their minerals into the broth: the length of cooking and the addition of an acidic component to the cooking liquid. Simmer grass-fed bones for up to 24 hours in acidic liquid (for instance, by adding some vinegar or lemon juice to the water) to make the minerals more available. For a general, customizable bone broth recipe, see Dr. Allison Siebecker’s version, available here in her article, “Traditional Bone Broth in Modern Health and Disease.”
 Osteoarthritis Cartilage. 2012 Aug;20(8):809-21.
 Clin Interv Aging. 2012; 7: 267–273.
 Townsend Ltr. 2005 Feb/Mar.
 Am J Physiol. 1982 Feb;242(2):G85-8.
 Pathophysiology. 2000 Apr;7(1):69-73.
 Clin Rev Allergy Immunol. 2012 Feb;42(1):71-8.
 Clean Gut. p. 191.
 J Agric Food Chem. 2012 Apr 25;60(16):4096-101.
 Calcif Tissue Int. 1994 Jun;54(6):486-8.