Tier 2 — strong

A randomized controlled trial on the efficacy and safety of a food ingredient, collagen hydrolysate, for improving joint comfort

P. Benito-Ruiz, M.M. Camacho-Zambrano, J.N. Carrillo-Arcentales, M.A. Mestanza-Peralta, C.A. Vallejo-Flores, S.V. Vargas-López, R.A. Villacís-Tamayo, L.A. Zurita-Gavilanes
International Journal of Food Sciences and Nutrition 2009 60(Suppl 2):99–113

Bibliography

PubMed
PMID 19212858
DOI
10.1080/09637480802498820
Funding
The accessible primary bibliographic record does not provide a funding statement. Later secondary reviews have classified this study as industry-sponsored, but those secondary classifications are not treated here as a verbatim funding disclosure from the original article.
Competing interests
No competing-interests declaration is visible in the accessible primary bibliographic record. Later secondary sources describe commercial sponsorship/manufacturer involvement; this record does not attribute those secondary statements to the original article as if they were author disclosures.

Study snapshot

DesignMulticentre, randomised, double-blind, placebo-controlled trial
ModelAdults with primary osteoarthritis of the knee (radiographically confirmed)
Sample250 randomised across multiple Ecuadorian and Spanish sites; both sexes
Intervention10 g/day collagen hydrolysate (food ingredient) versus placebo, once daily orally, for 6 months (24 weeks)
Duration6 months (24 weeks)
EndpointsKnee joint comfort — visual analogue scale (VAS) for pain; WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score for pain, stiffness, function; SF-36 quality-of-life questionnaire; Safety (adverse events); Responder criteria (OMERACT-OARSI)

What the study showed, in plain terms

Knee osteoarthritis is one of the most common causes of chronic joint pain in adults over 40. Standard treatments — paracetamol, non-steroidal anti-inflammatories, physical therapy, and eventually surgery — either don't fully control the pain or carry side effects that make long-term use difficult. Because collagen is the primary building block of joint cartilage, researchers hypothesised that swallowing collagen daily might reduce knee osteoarthritis symptoms.

This 2009 multicentre trial was one of the largest to date on collagen for knee osteoarthritis. Two hundred and fifty adults with radiographically-confirmed knee osteoarthritis were recruited across seven hospitals in Spain and Ecuador. They were randomly assigned to take either 10 grams of collagen hydrolysate or a placebo daily for six months. Neither the patients nor the study doctors knew who was getting what. Pain and function were tracked using standardised questionnaires: a visual analogue scale for pain, the WOMAC osteoarthritis index for daily-life symptoms, and the SF-36 quality-of-life survey.

Patients taking collagen reported significantly improved knee comfort by the six-month mark. The improvement was reported over months rather than as an immediate effect. That timing does not establish cartilage remodelling, and the trial did not demonstrate structural cartilage repair. The trial contributes to evidence that this collagen hydrolysate may improve some knee-osteoarthritis symptoms, while leaving structural disease modification and generalization to other products unresolved.

Key findings

  • In this multicentre randomized placebo-controlled trial, 250 adults with knee osteoarthritis were assigned to 10 g/day collagen hydrolysate or placebo for 24 weeks.
  • The published trial reported improvement in joint-comfort outcomes with collagen hydrolysate compared with placebo over the treatment period.
  • Pain, WOMAC and quality-of-life measures were symptom and function endpoints; the study did not measure cartilage structure or demonstrate structural disease modification.
  • Symptom differences developed over months rather than immediately. That timing does not establish cartilage remodelling or identify a mechanism.
  • The published safety results were generally reassuring over six months, but the study was not designed to establish long-term safety beyond the trial period.

What this study can and cannot tell us

  • The published abstract does not report complete effect sizes and confidence intervals for every endpoint, limiting precise assessment of the magnitude and uncertainty of individual outcomes.
  • Later systematic reviews report industry sponsorship by Protein S.A.; the original abstract does not describe the sponsor's role in study design, analysis, or reporting.
  • The population was recruited in Spain and Ecuador; generalisability to other populations is uncertain.
  • Only one collagen dose, 10 g/day, was tested, so no dose-response relationship was established.
  • The 24-week study assessed symptoms and function but did not test radiographic progression, cartilage repair or joint-replacement risk.
  • A multicentre design improves geographic breadth but can introduce variability in outcome assessment across sites.

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Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction Dr. Amr Yasser, PhDCardiometabolic, Musculoskeletal, Gut & Bioavailability Dr. Abdulla Mostafa, PhDCellular Senescence, Neurological, Mitochondrial & Brain-Ageing Biology