1 April 2024
Eben van Tonder

Introduction

Theodore Udeh, a research collaborator from Nigeria reports on a fascinating use of meat in healing bone fractures. He recalls a discussion he had with a certain Mr. Peter whom he met in Gaji Village in Bauchi state in East Nigeria. He recalls their “discussion on the traditional preparation of chicken in Nigeria, particularly from Mr. Peter’s native region of Benue.” Theodore recalls that their “conversation unveiled the medicinal application of chicken in treating fractured bones, a practice prevalent among the people of Benue. For male fractures, herbalists would utilize a premature male chicken, ensuring that the individual could consume the meat and entire bone post-preparation. Conversely, for female fractures, a female chicken would be used, with a virgin female overseeing the preparation process. The preparer would abstain from sexual activity during this time. Every part of the chicken, particularly the bones, would be consumed by the fracture victim. Additionally, Mr. Peter highlighted the collection of chicken fat to create herbal medicine, applied to the affected area. (TU)

I was eager to delve into the scientific background of this. Through a process of careful observation, ancients were able to develop traditions whereby certain parts of an animal would be consumed as treatment for certain ailments. These traditions were incorporated in religious beliefs which encapsulated it and ensured its transmission over multiple generations. The basis for many traditional beliefs and religious practices such as the offering of blood is therefore observation with a solid basis in the the natural world. Decades and in many instances, millennia later, modern science would confirm these observations.

The account by Mr Peter is a beautiful example of the power of collagen and it leads us into a deeper look into these amazing molecules. I frame the discussion in the light of the example above where whole chicken, including the bone is consumed to assist in the healing of a bone fracture.

General Overview

Collagen is the most abundant protein in the human body, providing structure to much of our tissue, including skin, bones, tendons, and ligaments. There are at least 16 types of collagen, but the majority of collagen in the body consists of types I, II, and III. Collagen types I and II are particularly important for their distinct roles in the body’s structure and function.

-> Collagen Type I

• Source: Collagen type I is predominantly found in the skin, bones, tendons, fibrous cartilage, connective tissue, and teeth. It comes mainly from the skin and bones of animals and is the most abundant collagen type in the human body.
• Function: Type I collagen is essential for the healing of bone fractures as it is the primary collagen found in bones. It provides the matrix for bone mineralization and is critical in the bone healing process. Additionally, it’s crucial for the strength of tendons, skin elasticity, and overall skin health.
• Structural Characteristics: Collagen type I fibres are densely packed and provide high tensile strength to tissues. This structural property is what makes it so effective in supporting skin and bone health.

Collagen Type II

• Source: Collagen type II is primarily found in elastic cartilage, which makes up the joints. It’s derived mostly from cartilage, such as that found in chicken and bovine sources.
• Function: Type II collagen is vital for the health and integrity of cartilage and is therefore essential in supporting joint health. While it’s not directly involved in bone healing like type I, it plays a crucial role in maintaining joint function and can be beneficial in conditions like osteoarthritis by helping to maintain the health of cartilage.
• Structural Characteristics: Collagen type II fibres are more loosely packed than type I and are found in cartilage, providing it with elasticity and resistance to intermittent pressures.

Structural Differences and Implications for Healing and Health

The main structural difference between collagen types I and II lies in their amino acid composition and the organization of their fibres, which dictates their function and location in the body. Collagen type I’s dense, tightly packed fibres provide structural support and tensile strength necessary for skin and bones, making it ideal for healing bone fractures and supporting skin and tendon health. In contrast, the more loosely organized fibres of type II collagen contribute to the elasticity and cushioning required for healthy cartilage and joint function.

For healing a bone fracture, collagen type I derived from sources like bovine hide or marine collagen, would be most beneficial due to its critical role in bone structure and repair. For strengthening tendons and improving skin health, collagen type I also plays a significant role, given its abundance in these tissues. Collagen type II often derived from chicken cartilage, may be more beneficial for individuals looking to support joint health and alleviate joint-related issues.

Delving Deeper

We noted that collagen types I and II differ in their amino acid compositions, which contribute to their unique structural properties and functions within the body. Let’s look a bit closer. Both types of collagen are composed of three polypeptide chains, forming a triple helix structure, but the specific sequence of amino acids in these chains and the post-translational modifications they undergo can vary between types, influencing their physical properties and roles in tissue.

-> Common Features

Before delving into the differences, it’s important to note that all collagen types share a common motif in their amino acid sequence: Glycine-Proline-X or Glycine-X-Hydroxyproline, where “X” can be any amino acid. This repetition is crucial for the formation of the collagen triple helix structure. Glycine, being the smallest amino acid, is essential because it fits into the centre of the triple helix. Proline and hydroxyproline contribute to the stability of the helix through hydrogen bonding.

Differences in Amino Acid Composition and Implications

->Amino Acid Composition:

• Type I Collagen: Type I collagen, being the most abundant in the human body, has a slightly higher proline and hydroxyproline content compared to type II. This composition is critical for the tensile strength of tissues like skin, bone, and tendons, where type I collagen is predominantly found.
• Type II Collagen: While also containing a significant amount of proline and hydroxyproline, type II collagen is enriched in other amino acids that may contribute to its ability to form more loosely packed fibers in cartilaginous tissues, providing cushion and flexibility to joints.

-> Structural Differences and Functions:

• The structural differences between type I and II collagen arise not only from their amino acid composition but also from the way their fibers are organized. Type I collagen fibers are densely packed, providing high tensile strength necessary for the structural integrity of skin, bone, and tendons. This dense packing is facilitated by the specific arrangement of amino acids that allows for tight packing of the collagen molecules.
• In contrast, type II collagen fibers are found in cartilage and are designed to resist intermittent pressure while providing flexibility and cushioning to joints. The differences in amino acid content and organization contribute to a less dense packing than type I, suitable for cartilage’s function.

-> Post-Translational Modifications:

• Both types of collagen undergo post-translational modifications, such as hydroxylation of proline and lysine residues, which are critical for the stability of the collagen triple helix and the formation of cross-links between collagen molecules. Variations in these modifications can affect the mechanical properties of the collagen fibres, further distinguishing their functions in the body.

Post-translational modifications (PTMs) refer to the chemical modifications that proteins undergo after they have been synthesized (translated) by ribosomes in the process of protein biosynthesis. These modifications can occur at specific amino acid side chains or peptide linkages and are essential for a protein’s activity, stability, location, and interaction with other molecules. PTMs can dramatically alter a protein’s properties and functions without altering its primary amino acid sequence.

In the context of collagen, including types I and II, post-translational modifications are crucial for stabilizing the triple helix structure, forming intermolecular cross-links, and ensuring proper assembly and function of the collagen fibrils. Key PTMs in collagen synthesis include:

1. Hydroxylation: Proline and lysine residues in the collagen polypeptide chains can be hydroxylated to form hydroxyproline and hydroxylysine, respectively. This modification is catalyzed by the enzymes prolyl hydroxylase and lysyl hydroxylase, which require vitamin C as a cofactor. Hydroxyproline is critical for the stability of the collagen triple helix, as it enhances hydrogen bonding within the helix. Hydroxylysine is involved in the formation of cross-links between collagen molecules and can also serve as attachment points for carbohydrates.
2. Glycosylation: Some hydroxylysine residues undergo glycosylation, where sugars like glucose or galactose are attached. This modification can affect collagen’s solubility and interactions with other matrix components.
3. Formation of Disulfide Bridges: In some types of collagen, the C-terminal propeptide regions form disulfide bridges. This helps in the proper alignment of the triple helix before it is fully formed.
4. Cleavage of Propeptides: Collagen is synthesized as a precursor molecule called procollagen, which has extra peptide sequences at both ends (propeptides). These propeptides are cleaved off by specific proteases once the procollagen molecule is secreted into the extracellular space, allowing the collagen molecules to assemble into fibrils.
5. Cross-linking: After the triple helix is formed and the propeptides are cleaved, collagen molecules are further stabilized by the formation of covalent cross-links between lysine and hydroxylysine residues. This cross-linking, catalyzed by the enzyme lysyl oxidase, is crucial for the tensile strength and resistance of collagen fibres.

These post-translational modifications are essential for the proper functioning of collagen in the body. They not only ensure the structural integrity and mechanical properties of collagen-containing tissues but also play a role in tissue repair, signalling, and interaction with other proteins and molecules in the extracellular matrix.

Does it Matter What Collagen We Consume?

An interesting question now arises. Considering that the body synthesizes collagen from amino acids obtained through the digestion of dietary proteins, including ingested collagen, how does the body determine which type of collagen to produce in specific tissues? Is there a relationship between the type of collagen we consume and the type of collagen synthesized by the body? Furthermore, how is this synthesis process regulated within the body to ensure the appropriate type of collagen is produced in the correct locations?

The process of collagen synthesis in the body is quite sophisticated and does not directly utilize ingested collagen types (such as type I or II) to produce more of the same type within the body. Instead, collagen synthesis involves the assembly of amino acids into collagen peptides, following the genetic instructions encoded within cells. These amino acids are sourced from the overall pool available in the body, which are obtained through the digestion of dietary proteins or the breakdown of body proteins, not from the direct conversion of ingested collagen.

The specific type of collagen that a cell produces (be it type I, II, or any other type) is determined by the cell’s function and the genes it expresses, not by the specific type of collagen consumed in the diet. For instance, fibroblasts in connective tissues primarily produce type I collagen, essential for skin and bone health, while chondrocytes in joint cartilage produce type II collagen, crucial for joint function and health.

However, ingesting collagen indeed means that more collagen is produced! The mechanism, however, is indirect.

While ingesting collagen does not directly translate to an increase in the same type of collagen in the body, dietary collagen can provide essential amino acids and bioactive peptides. These components can play a significant role in supporting collagen production by supplying the necessary building blocks and potentially influencing collagen synthesis through various mechanisms.

Research into collagen and its impact on the human body has revealed that the digestion of collagen can lead to the formation of bioactive peptides—small sequences of amino acids that, once released, may have various physiological effects. When collagen is ingested and hydrolyzed (broken down) during digestion, these bioactive peptides are released and absorbed into the bloodstream. The notion is that these peptides can act as signalling molecules within the body, influencing cellular activities including the synthesis of new collagen.

-> Mechanisms of Action:

Here is how it works.

1. Stimulation of Collagen Production: Some studies suggest that specific collagen peptides can stimulate the cells that produce collagen (such as fibroblasts in the skin, chondrocytes in cartilage, and osteoblasts in bones) to increase their collagen output. This is believed to occur through the activation of certain signalling pathways that lead to the upregulation of collagen gene expression.
2. Activation of Growth Factor Production: Collagen-derived peptides may also promote the production of growth factors, such as transforming growth factor-beta (TGF-β), which are crucial for the synthesis and repair of the extracellular matrix and collagen in various tissues.
3. Enhancing Collagen Cross-Linking: Beyond stimulating collagen production, some peptides may influence the post-translational modifications of collagen, enhancing its cross-linking and stabilization in the extracellular matrix. This process is vital for the mechanical strength and structural integrity of collagen fibres.

These effects are believed to be mediated through the interaction of collagen peptides with specific receptors on the surface of target cells, initiating intracellular signalling cascades that lead to an increase in collagen production. It is important to note that the efficacy of collagen peptides can depend on factors such as their concentration, molecular weight, and amino acid composition, which can influence their bioavailability and biological activity.

While it might seem intuitive that consuming a specific type of collagen would directly increase the production of that same type within the body, the process is, as we noted, more complex and indirect. When you ingest collagen, regardless of the type, it’s broken down into its constituent amino acids and smaller peptides during digestion. These components do not retain the original “identity” of the collagen type they came from (e.g., type I, II, III, etc.). Once absorbed into the bloodstream, these amino acids and peptides become available for the body to use as building blocks for protein synthesis, according to its current needs and the specific instructions encoded in the cells’ DNA.

The stimulation of collagen-producing cells by specific peptides does not directly correlate with the ingestion of a particular type of collagen leading to the production of that same type. Instead, what research suggests is that certain bioactive peptides—resulting from the digestion of any collagen type—can signal the body’s cells to produce more collagen. These signals can activate fibroblasts, chondrocytes, osteoblasts, and other cells to synthesize more collagen, but the type of collagen synthesized is determined by the cell type and its genetic programming, not directly by the collagen type ingested.

For example, fibroblasts in the skin are programmed to produce mainly type I collagen, the most abundant form in the skin, regardless of whether the collagen peptides originated from type I, II, or III collagen ingestion. Similarly, chondrocytes in cartilage will predominantly produce type II collagen, following their genetic instructions.

In essence, while ingesting collagen can support overall collagen production in the body by providing necessary amino acids and stimulating bioactive peptides, it does not dictate a one-to-one correspondence where consuming a specific type of collagen directly increases the production of that same type. The body’s utilization of ingested collagen is a beneficial but more generalized support for collagen synthesis across different tissues.

The Consumption of Young Chicken to Aid Bone Fracture Healing

Now we return to the interesting case study from Nigeria where consuming a young chicken completely, bones and all, is associated with the healing of bone fractures.

Here I try and quantify the exact amount of collagen intake from consuming an entire chicken (including bones) versus a plant-based diet or consuming meat from a cow without bones involves considering the collagen content in different tissues and the absence of collagen in plant-based foods. Since collagen is a protein found exclusively in animal tissues, especially in connective tissues, skin, and bones, the comparison will inherently show a significant difference in collagen intake between these dietary choices.

-> Consuming an Entire Chicken (Including Bones)

• Collagen Content: Chickens are rich in collagen, particularly in the skin, connective tissues, and bones. Consuming the entire chicken, including making broth from the bones, or consuming the softer bones of a young bird, will provide a substantial amount of collagen. Bones and skin are especially collagen-dense, with the broth made from bones being a rich source of gelatin (cooked collagen) and other nutrients conducive to collagen synthesis, like glycine and proline.

-> Plant-Based Diet

• Collagen Content: A plant-based diet contains no collagen because collagen is exclusive to animal-derived foods. However, certain plant foods can support collagen synthesis in the body by providing necessary vitamins and amino acids. For example, vitamin C, found in citrus fruits and leafy greens, is essential for collagen synthesis. Similarly, lysine and proline, amino acids found in various plant proteins, are important for collagen production. Despite this, the direct intake of collagen from plant-based foods is 0%.

-> Consuming Beef (Without Bones)

• Collagen Content: Beef is a good source of collagen, particularly found in the connective tissues and, to a lesser extent, in the muscle meat. However, excluding bones (and thus, bone broth) from the diet significantly reduces the amount of collagen intake compared to consuming an entire chicken with bones. Muscle meat contains less collagen compared to skin and bones.

-> Projected Percentages

Without detailed analysis, we can draw the following general conclusions.

• Consuming an entire chicken with bones will provide the highest collagen intake of these options, particularly if the bones are consumed directly or if a broth is made from the harder bones.
• A plant-based diet would result in 0% direct collagen intake, though it can support the body’s collagen production indirectly.
• Consuming beef without bones would offer collagen intake lower than that from an entire chicken (including bones) but significantly higher than a plant-based diet, primarily through the consumption of connective tissues that are part of the meat cuts.

It’s important to note that the body’s ability to synthesize collagen internally from amino acids and other nutrients is crucial. Therefore, a balanced diet that includes a variety of nutrients supportive of collagen synthesis can be beneficial for maintaining healthy collagen levels in the body, regardless of direct collagen intake from the diet.

The Benefit of Beef-Bone In

This discussion leads to an interesting alternative application of the exact same process namely in beef bone-in products. Consuming bone-in beef can increase your collagen intake due to collagen and other beneficial compounds being released from the bones, especially when the meat is cooked for extended periods. Cooking methods that involve slow simmering or braising, such as making stews or bone broths, can extract collagen (which transforms into gelatin upon cooking), amino acids, and minerals from the bones and connective tissues. These nutrients then become part of the cooking liquid and the meat itself, enhancing its nutritional value.

Collagen is most abundant in the connective tissues and bones of animals. During the cooking process, the heat breaks down collagen into gelatin, making it more easily digestible and absorbable. This means that dishes prepared with bone-in beef not only potentially offer more flavour but also a richer source of collagen compared to cooking meat alone without the bones.

Bones contain marrow, which is rich in nutrients, including fatty acids, vitamins, minerals, and collagen, contributing to the overall nutritional profile of the meal. The nutrients leached from the bones into the broth or sauce are then consumed along with the meat, increasing your intake of these beneficial compounds. This can be incorporated into a stewing pack which is high in collagen, meat bone-on and beef bones that has been split to expose the marrow.

While consuming bone-in beef and the associated broth or juices can increase your collagen intake, the exact amount of collagen consumed will depend on several factors, including the cooking time, temperature, and the specific part of the animal the bones are from. Long, slow cooking methods are more effective at breaking down collagen and releasing it and other nutrients into the cooking liquid.

Conclusion

Researching old Nigerian meat-eating traditions within a spiritual context revealed a startling connection between collagen and healing bone fractures. What kind of collagen you ingest is not the important question, but the fact that you should consume more collagen if you suffer from a bone fracture stands the test of modern scientific scrutiny. As far as the application of animal fat to the affected area, it probably has more relevance if there is an accompanying external wound also. The reason for this is quite simply that animal fats can act as emollients, helping to keep the wound moist and potentially preventing the drying and cracking of skin around wounds. Moist wound environments are known to support the healing process. Another benefit will be in barrier formation. By forming a physical barrier over a wound, animal fats might protect the area from external contaminants. This made perfect sense in ancient times or in environments where advanced dressings are not available which will give the same benefit as the fat, without the risk of infection. Remember that the fat may not be sterile.

Boiling animal fat and allowing it to set before applying it to a wound in a rural environment could potentially reduce some risks associated with raw animal fats, such as the presence of pathogens. Boiling can sterilize the fat, killing bacteria and other microorganisms that might be present, which could make it a safer option than applying raw fat directly to a wound. However, it’s important to approach this method with caution. While boiling can kill bacteria, ensuring the fat remains sterile until it’s applied to the wound requires careful handling. Any subsequent contamination after boiling could reintroduce bacteria to the fat. There is also still the concern that animal fats, even when boiled, might not be optimal for wound healing and could potentially trigger an inflammatory response or delay healing due to their composition. Animal fats also do not contain specific wound-healing properties or agents (such as growth factors, antiseptics, or antibiotics) that are present in modern wound care products. All this being said, I can understand why this was a popular treatment for external wounds in the old days especially if that was the only option on the table.

References

Bello, A. E., & Oesser, S. (2006). Collagen hydrolysate for the treatment of osteoarthritis and other joint disorders: a review of the literature. Current Medical Research and Opinion, 22(11), 2221-2232.

Proksch, E., Segger, D., Degwert, J., Schunck, M., Zague, V., & Oesser, S. (2014). Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study. Skin Pharmacology and Physiology, 27(1), 47-55.

Shaw, G., Lee-Barthel, A., Ross, M. L., Wang, B., & Baar, K. (2017). Vitamin C–C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. The American Journal of Clinical Nutrition, 105(1), 136-143.

Theodore Ejikemme Yakubu Ude II (TE) from personal correspondence.