Nutrition advice has become remarkably good at telling us what to avoid. We are warned about excessive sugar, processed foods, trans fats, alcohol, and excess calories. Over the decades, fat has been condemned and partly rehabilitated, eggs have moved from dietary villain to respectable food, and carbohydrates have alternated between essential fuel and metabolic poison. Yet amid this constant stream of nutritional advice, one question is asked surprisingly rarely: what have modern diets quietly stopped providing?
An intriguing scientific debate surrounding collagen suggests the answer may be more significant than many realise.
Collagen is the body's most abundant structural protein. It provides strength and flexibility to skin, tendons, ligaments, cartilage, bones and blood vessels. Much of collagen is built from the amino acid glycine. Traditionally, glycine has been classified as a "non-essential" amino acid because the human body can manufacture it. However, an increasing number of researchers argue that this classification may be misleading. While the body certainly produces glycine, it may not always produce enough to satisfy the demands of collagen synthesis, particularly during ageing, illness, injury, or prolonged physical activity. In these circumstances, glycine may become what nutritionists call a conditionally essential amino acid.
The science remains unsettled. Some researchers estimate that humans may require considerably more glycine each day than can be produced internally and obtained from the average modern diet. Others argue that healthy individuals generally compensate well and that the body adapts to varying circumstances. As with much of nutrition science, certainty remains elusive. Yet the debate itself raises an important question that extends well beyond one amino acid.
Perhaps the real issue is not that our bodies have suddenly become deficient? Perhaps modern civilisation has fundamentally changed the foods we eat?
For most of human history, people consumed far more of the whole animal than they do today. Skin, tendons, cartilage, marrow and connective tissue were valuable sources of nourishment. Tough cuts became slow-cooked stews. Bones became broths. Chicken skin was eaten rather than discarded. Fish skin often remained attached. Little was wasted because food itself was precious.
By contrast, the modern supermarket encourages a very different approach. Consumers are drawn towards skinless chicken breasts, extra-lean mince, trimmed steaks and neatly packaged fillets. The collagen-rich portions of the animal are frequently discarded, processed into pet food, or diverted into industrial products. In pursuing convenience and lean meat, we may have unintentionally reduced our intake of nutrients that previous generations consumed almost automatically.
This possibility illustrates a broader truth about human progress. Technological advances often solve one problem while quietly creating another. Refrigeration, food preservation, mechanised agriculture and global supply chains have dramatically improved food security and reduced hunger across much of the world. Yet these same developments have encouraged increasingly selective eating habits that may narrow the diversity of nutrients reaching our plates.
The collagen debate therefore becomes a case study in a larger principle. Modernity often changes not only how much we eat, but what we eat. The disappearance of collagen-rich foods from everyday diets may represent one example of this broader nutritional transition.
None of this means that collagen alone explains healthy ageing. Collagen synthesis depends upon many factors. Adequate total protein remains essential. Vitamin C is required for proper collagen formation. Minerals such as copper and iron also play important roles. Regular physical activity, particularly resistance exercise, provides the mechanical stimulus that encourages the body to build and remodel connective tissue. Even abundant glycine cannot compensate for deficiencies in these other requirements.
Nor does the evidence justify panic or the assumption that everyone requires expensive supplements. Collagen peptide supplements may offer modest benefits for some individuals, particularly regarding skin elasticity or joint comfort, but they are not miracle cures. Before reaching for another tub of powdered collagen, it may be worth asking whether modern eating habits have simply abandoned foods that naturally supplied these nutrients for countless generations.
The practical response is refreshingly simple. Eat adequate amounts of quality protein. Ensure sufficient vitamin C through fruit and vegetables. Engage in regular resistance exercise to stimulate the body's natural collagen production. Consider occasionally including collagen-rich foods such as slow-cooked beef shanks, oxtail, homemade bone broths, chicken with the skin, fish skin, and other traditional dishes that make use of connective tissue rather than discarding it. These foods nourished generations long before collagen became a fashionable supplement.
The collagen debate reminds us that progress is rarely free. Every technological advance solves some problems while creating others. We have mastered refrigeration, food processing, selective breeding and global supply chains, yet in doing so we may have quietly abandoned parts of the human diet that nourished countless generations. Whether the emerging glycine hypothesis ultimately proves entirely correct or only partly so, it raises a valuable question: have we become so efficient at producing food that we have forgotten what food once was?
Sometimes the greatest advances in health come not from discovering an entirely new nutrient, but from rediscovering an old one. The future of nutrition may depend as much on recovering lost wisdom as on inventing new science. In our enthusiasm for modern convenience, we may simply have left some of nature's most valuable foods behind.
https://articles.mercola.com/sites/articles/archive/2026/06/11/collagen-crisis.aspx