Tier 4 — mechanistic

Bone broth unlikely to provide reliable concentrations of collagen precursors compared to supplemental sources of collagen used in collagen research

Rebekah D. Alcock, Gregory C. Shaw, Louise M. Burke

International Journal of Sport Nutrition and Exercise Metabolism 2019 29(3):265–272

Bibliography

DOI: 10.1123/ijsnem.2018-0139
PubMed: PMID 29893587
Funding: No external grant funding statement in the extracted data. Authors were affiliated with the Australian Institute of Sport (Bruce, Canberra, ACT), Mary Mackillop Institute for Health Research at Australian Catholic University, and Brumbies Rugby (Bruce, Canberra, ACT).
Competing interests: Competing interests statement (verbatim): "The authors declare no conflict of interest." Lead author Rebekah D. Alcock affiliated with Brumbies Rugby (professional sports team) in addition to academic institution. Co-author Louise M. Burke is a highly-published sports nutrition researcher at the Australian Institute of Sport. No commercial ties to a specific bone broth or collagen manufacturer surfaced.

Study snapshot

Design	Analytical laboratory comparison — quantification of collagen-precursor amino acids across multiple bone broth preparations and standard collagen supplement products
Model	Not applicable — analytical study of food and supplement products
Sample	Not applicable — multiple bone broth batches (chicken bone, beef bone, home-prepared with and without vinegar, commercial powder-form) compared to standard collagen hydrolysate research doses
Intervention	Not applicable — analytical characterisation only
Duration	Not applicable
Endpoints	Hydroxyproline content per serving; Glycine content per serving; Proline content per serving; Hydroxylysine content per serving; Lysine content per serving; Leucine content per serving

What the study showed, in plain terms

Bone broth has been widely marketed as a natural, whole-food source of collagen — a "traditional" alternative to buying a collagen supplement powder. The intuitive logic is straightforward: bone broth is made by simmering bones for hours, which extracts collagen from them into the broth. So a mug of bone broth should, in theory, deliver the same collagen-precursor amino acids as a scoop of collagen powder. The problem is that no one had rigorously measured whether this is actually true.

This 2019 analytical study did exactly that. The researchers prepared bone broth in multiple ways — chicken bone, beef bone, home-simmered with and without added vinegar to extract more minerals, and a commercial powder-form product — and measured the concentration of the specific amino acids that matter for collagen synthesis: hydroxyproline, glycine, proline, hydroxylysine, lysine, and leucine. They then compared these to the amino acid content of standard doses of collagen supplements used in published research trials.

The finding is unambiguous: bone broth contains far less of the key collagen-precursor amino acids per serving than a research-grade collagen supplement dose. Even the highest-yielding broth (the commercial powder-form product) came nowhere close to matching the hydroxyproline content of a typical 10–15 g supplemental dose. Moreover, the amino acid content varied enormously between broth preparations — meaning consumers cannot reliably estimate how much collagen precursor they are consuming from a batch of home-made broth. For anyone hoping to replicate the trial-dose collagen intake from bone broth alone, the practical implication is that they would need to consume implausibly large volumes daily. Bone broth may still have culinary or comfort value, but for the specific goal of dosing collagen precursors it is not a reliable substitute for standardised supplementation.

Key findings

Hydroxyproline content per typical serving of bone broth ranged from approximately 2,950–6,500 mg, versus ~10,000 mg in a standard 10 g research-grade collagen supplement dose.
Glycine content per serving of bone broth ranged approximately 5,200–11,417 mg, versus ~17,444 mg in a standard supplement dose.
Proline content per serving of bone broth ranged approximately 3,200–6,983 mg, versus ~10,667 mg in a standard supplement dose.
Highest-yielding preparation was beef bone broth, but still fell substantially below supplement-equivalent doses of key collagen precursors.
Home-prepared broths showed wide batch-to-batch variability, making them unreliable as a standardised collagen source.
Addition of vinegar to the broth preparation increased mineral extraction but did not substantially increase amino acid content.
Commercial powder-form bone broth products contained more concentrated amino acids per serving than liquid home-prepared broths but still fell below supplemental research doses.

What this study can and cannot tell us

Analytical study — measures composition of the food/supplement, not what actually enters the bloodstream. Bioavailability of amino acids from bone broth vs from a collagen hydrolysate could theoretically differ, though there is no reason to expect it does substantially.
Limited number of preparations tested — commercial bone broth products vary widely, and this study only sampled representative examples.
Amino acid analysis technique and detection limits not extracted from the visible text — verify from full PDF for sensitivity limits.
Does not compare bone broth to whole-food dietary collagen precursors (e.g., meat with connective tissue, gelatin desserts) — some readers may draw an unfair comparison to only powder supplements.
Nutritional value of bone broth as a whole food (minerals, fluids, other nutrients) is not addressed — this is a narrowly-scoped comparison on collagen-precursor amino acids specifically.
Does not measure whether the peptide profile in bone broth (as opposed to isolated amino acids) matches that in hydrolysates — this could differ meaningfully.

Tier 2

Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study

Ehrhardt Proksch et al. · Skin Pharmacology and Physiology · 2014

Tier 3

Comparison of quantity and structures of hydroxyproline-containing peptides in human blood after oral ingestion of gelatin hydrolysates from different sources

Hiroki Ohara et al. · Journal of Agricultural and Food Chemistry · 2007