Tier 3 — preclinical

Assessment of effectiveness of oral administration of collagen peptide on bone metabolism in growing and mature rats

Jian Wu, Maiko Fujioka, Kiho Sugimoto, Gang Mu, Yoshiko Ishimi
Journal of Bone and Mineral Metabolism 2004 22(6):547–553

Bibliography

PubMed
PMID 15490264
DOI
10.1007/s00774-004-0522-2
Funding
A funding source is not reported in the PubMed record reviewed. The authors were affiliated with the Division of Applied Food Research, National Institute of Health and Nutrition, Tokyo, Japan.
Competing interests
A formal competing-interests statement is not shown in the PubMed record reviewed. The listed author affiliation is the National Institute of Health and Nutrition, Tokyo, Japan.

Study snapshot

DesignTwo parallel rat experiments — dose-ranging in growing males and calcium-deficient adult females — with control and multiple collagen peptide doses
ModelGrowing male Sprague-Dawley rats for dose-response and calcium-deficient mature female rats for bone-loss efficacy; the mature-rat model used dietary calcium deficiency rather than ovariectomy.
SampleTwo rat experiments with multiple treatment groups. The PubMed abstract reviewed does not report exact per-group sample sizes, so no exact n is asserted here.
InterventionGrowing male rats received control diet or collagen peptide at 0.166, 1.66, or 16.6 g/kg body weight/day for 4 weeks. In the mature-female experiment, rats first underwent 9 weeks of calcium deficiency, then 8 weeks of repletion with control, lower-dose collagen, higher-dose collagen, or normal-calcium diet conditions.
DurationExperiment 1: 4 weeks. Experiment 2: 9 weeks calcium-depletion followed by 8 weeks intervention (17 weeks total)
EndpointsFemoral BMD by DXA; Lumbar spine BMD by DXA; Kidney histology and organ weight; Body weight; Serum bone turnover markers

What the study showed, in plain terms

This 2004 rat study examined collagen-peptide intake at several very high weight-normalised doses in growing animals and in calcium-deficient adult females. Its purpose was to explore bone effects and tolerability in an animal model, not to establish a human safe upper intake.

Growing rats received doses equivalent to the study authors’ reference human supplement amount, ten times that amount, or one hundred times that amount for four weeks. Calcium-deficient adult female rats received lower dose tiers for eight weeks.

The highest dose in growing rats increased femoral bone mineral density but was also associated with kidney hypertrophy. Lower tested doses did not show that kidney finding. In calcium-deficient adult females, the higher collagen dose improved some bone-density measures. These results are useful preclinical context, but rat doses cannot be converted directly into a human safety margin and the kidney finding should not be treated as a defined human toxicity threshold.

Key findings

  • In growing rats, the reference-equivalent and 10-fold dose groups did not show a significant femoral-BMD advantage over controls.
  • At the 100-fold dose, femoral BMD was higher, but kidney hypertrophy was also observed.
  • In calcium-deficient adult female rats, the higher collagen dose improved femoral and lumbar bone-density measures compared with lower-dose or deficient-control groups.
  • The reference-equivalent dose did not significantly improve BMD in the calcium-deficient adult model.
  • The study provides preclinical dose-response and tolerability information only; it does not establish a human safe upper intake or prove safety of long-term high-dose supplementation.

What this study can and cannot tell us

  • This is a rat study; species differences in peptide transport, metabolism and renal handling prevent direct dose translation to humans.
  • Rat weight-normalised doses do not translate 1:1 to human doses because of metabolic scaling.
  • The highest dose that produced kidney hypertrophy was far above realistic supplement intake, so it should not be presented as a human toxicity threshold.
  • Group sizes were small, as is common in preclinical work, limiting power to detect subtle effects.
  • Only selected bone and gross kidney outcomes were measured; the study was not a comprehensive organ-system safety assessment.
  • Only one collagen-peptide preparation was tested, so generalisability to other hydrolysates is uncertain.
  • Formal funding and competing-interest disclosures are not available in the PubMed record reviewed.

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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