Our Summary
Bone broth has become enormously popular as a natural source of collagen, with proponents claiming it supports joint health, skin, and connective tissue repair. But this 2019 study published in the International Journal of Sport Nutrition and Exercise Metabolism by Australian researchers Alcock, Shaw, and Burke put that claim to the test by directly measuring the amino acid content of bone broth and comparing it against the doses used in collagen research. The researchers analyzed both commercially prepared and self-prepared bone broths made under standardized and non-standardized recipes, measuring levels of the key collagen-building amino acids including glycine, proline, hydroxyproline, lysine, hydroxylysine, and leucine, all of which the body uses to synthesize collagen. The findings were clear and consistent: amino acid concentrations in bone broth, even when made to a standardized recipe, were significantly lower than the amounts provided by a therapeutically relevant dose of collagen supplements, the doses actually shown in research to support collagen synthesis. The variability problem was equally striking: non-standardized homemade recipes produced wildly inconsistent amino acid levels depending on preparation method, ingredients, and cooking time, with cafe-prepared broths tending to be higher and commercial packaged broths tending to be the lowest of all. The study concludes that while bone broth is not without nutritional value, it cannot be considered a reliable or consistent substitute for supplemental collagen when the goal is to deliver the specific collagen precursor amino acids at doses that research has associated with meaningful effects on tissue repair and collagen production.
PMID: 29893587
Abstract
Intake of dietary sources of collagen may support the synthesis of collagen in varying tissues, with the availability of key amino acids being a likely contributor to its effectiveness. This study analyzed commonly consumed preparations of bone broth (BB) to assess the amount and consistency of its amino acid content. Commercial and laboratory-prepared samples, made with standardized and variable (nonstandardized) protocols, were analyzed for key amino acids (glycine, lysine, proline, leucine, hydroxyproline, and hydroxylysine). The main finding of this study was that amino acid concentrations in BB made to a standardized recipe were significantly lower for hydroxyproline, glycine, and proline (p = .003) and hydroxylysine, leucine, and lysine (p = .004) than those provided by a potentially therapeutic dose (20 g) of reference collagen supplements (p > .05). There was a large variability in the amino acid content of BB made to nonstandardized recipes, with the highest levels of all amino acids found within the café-prepared varieties. For standardized preparations, commercial BBs were lower in all amino acids than the self-prepared varieties. There were no differences (p > .05) in the amino acid content of different batches of BB when prepared according to a standardized recipe. If the intake of collagen precursors is proven to support the synthesis of new collagen in vivo, it is unlikely that BB can provide a consistently reliable source of key amino acids. Research on the provision of key amino acids from dietary sources should continue to focus on the standard sources currently being researched.
Keywords: gelatine; glycine; ligament; proline; protein; tendon.
