Bones contain an abundance of minerals as well as 17 different amino acids, many of which are found in broth as proteins like collagen and gelatin. Though the exact nutritional content varies based on the bones used, cooking time, and cooking method, the following nutrients are consistently found in most bone broths.
Bone Broth Benefits – Collagen
With 28 different types, collagen makes up about 30 percent of the protein in your body (4) and is the main component of connective tissues like cartilage, ligaments, tendons, bone, and skin. It is also present in the blood vessels, cornea, and lens of the eye. The name collagen comes from the Greek “kólla,” meaning “glue,” and the suffix “-gen,” which means “producing.” In fact, early glue was made from collagen more than 8,000 years ago, likely by boiling the skin and sinews of animals (5). In addition to providing structure, collagen also plays an important role in tissue development and regulation (6, 7).
Bone Broth Benefits -Gelatin
When collagen is simmered, it forms gelatin. This hydrolysis of collagen is irreversible and results in the breakdown of long collagen protein fibrils into smaller protein peptides. However, its chemical composition is very similar to its parent molecule, collagen (8). Gelatin is what gives bone broth or stock its Jell-O-like consistency once it has cooled.
Bone Broth Benefits -Glycosaminoglycans
Glycosaminoglycans (GAGs) are complex carbohydrates that participate in many biological processes. They can attach to proteins in order to form proteoglycans, which are integral parts of connective tissue and synovial fluid, the lubricant that surrounds the joint (9). If the connective tissue, such as tendons, ligaments, and cartilage, is still attached, the bones in broth will provide our bodies with the whole spectrum of GAGs, including keratan sulfates, dermatan sulfates, chondroitin sulfates, and hyaluronic acid, which are the raw materials for skin, bone, and cartilage formation.
Bone Broth Benefits -Glycine
Glycine is an amino acid that makes up more than a third of collagen. It also acts as a neurotransmitter, binding to glycine receptors present throughout the nervous system and peripheral tissues. Signaling through this receptor is particularly important in mediating inhibitory neurotransmission in the brainstem and spinal cord (10, 11).
Bone Broth Benefits -Proline
Proline is an amino acid that makes up about 17 percent of collagen. The addition of hydroxyl groups to proline significantly increases the stability of collagen and is essential to its structure. Though small amounts of proline can be manufactured in the body, evidence shows that adequate dietary proline is necessary to maintain an optimal level of proline in the body (12, 13). Proline is not typically thought of as a neurotransmitter, but it is able to weakly bind to glutamate receptors and glycine receptors (14).
Bone Broth Benefits -Glutamine
Glutamine is yet another important amino acid found in bone broth and is the most abundant amino acid in the blood (15). It is one of the few amino acids that can directly cross the blood–brain barrier (16). Intestinal epithelial cells and activated immune cells eagerly consume glutamine for cellular energy (17, 18).
Bone Broth Benefits -Bone marrow
Inside the center cavity of the bone is the bone marrow, consisting of two types, red and yellow. Both types contain collagen. Red bone marrow is the site of manufacturing for new immune cells and red blood cells, while yellow marrow consists of healthy fats (19, 20). It is thought that important nutritional and immune support factors might be extracted from marrow during cooking, but the bioavailability of these factors has not been studied.
Bone Broth Benefits -Minerals
Bone is also full of minerals, including calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sodium, and zinc (21). An acidic medium is necessary to extract these minerals from food. When making broth, always add a splash of vinegar or other acid in order to extract the most minerals from the bone.