Collagen to alleviate joint discomfort?

Naturally synthesised by the body, collagen is particularly found in joints and bones where it ensures cohesion, elasticity and tissue regeneration. Collagen fibres notably act as a cushion to reduce shocks between bones and pressures. Furthermore, collagen aids in the healing of tissues in case of damaged joints. This protein constitutes approximately 67% of the dry weight of cartilage. However, the efficiency of collagen production decreases over time. Certain sporting or professional activities can also contribute to prematurely wearing out joint collagen, which can increase the risks of osteoarthritis or, more generally, joint pain.

To prevent or alleviate them, some people embark on a collagen regimen. Most dietary supplements available on the market are based on collagen type II native or hydrolysed collagen. Several studies have been conducted on the effects of such supplementation. The majority have reported positive results in terms of pain relief and improvement in joint function. Furthermore, changes in cartilage degradation have been detected. The results of a few studies are presented in the table below.

However, there is a significant heterogeneity in terms of the design and implementation of studies, with often very small participant samples. Furthermore, the effects of collagen treatment are rarely compared to those of a placebo or, when they are, the effects of the placebos are not always considered. In addition, the studies do not indicate whether the effects of the supplementation have lasted over time and/or if the treatment was continued or discontinued.

Finally, one may question the effectiveness of theabsorption of collagen by the body, criticised by some researchers due to the significant molecular weight of collagen (300 kDa). Indeed, once ingested, it is broken down into amino acids in order to cross the intestinal barrier. These amino acids can then be used by the body to rebuild proteins, but it is not guaranteed that they will specifically form collagen. This also applies to collagen hydrolysate, which corresponds to collagen peptides. As a reminder, peptides are short chains of amino acids, not performing exactly the same functions as native proteins.

It is prudent to be cautious about the potential effects of collagen treatments on the joints.

• ALBERT A. & co. 24-Week study on the utilisation of hydrolysed collagen as a dietary supplement in athletes experiencing activity-related joint pain. Current medical research and opinion (2008).

• FLECHSENHAR K. & al. Alteration in knee osteoarthritis cartilage detected by delayed gadolinium enhanced magnetic resonance imaging following treatment with collagen hydrolysate: a pilot randomized controlled trial. Osteoarthritis and Cartilage (2011).

• BERNARDO M. & al. A Randomised Controlled Trial on the Impact of Oral Collagen Therapy on the Medial Knee Joint Space and Functional Outcome among Patients Diagnosed with Knee Osteoarthritis at the Veterans Memorial Medical Centre. PARM Procurement (2012).

• SHAMIE A. & al. Undenatured Type II Collagen (UC-II®) for Joint Support: A Randomised, Double-Blind, Placebo-Controlled Study in Healthy Volunteers. Journal of the International Society of Sports Nutrition (2013).

• VENKATESWARATHIRUKUMARA S. & co. A double-blind, placebo-controlled, randomised, clinical study on the efficacy of collagen peptide in osteoarthritis. Journal of the Science of Food and Agriculture (2014).

• SAKAI Y. & al. Absorption and Urinary Excretion of Peptides following Collagen Tripeptide Ingestion in Humans. Biological and Pharmaceutical Bulletin (2016).

• ATLAS O. & co. Impact of Native Type II Collagen Therapy on Knee Osteoarthritis: A Randomised Controlled Trial. The Eurasian Journal of Medicine (2016).

• LANE N. & co. Efficacy and tolerability of an undenatured type II collagen supplement in modulating knee osteoarthritis symptoms: a multicenter randomized, double-blind, placebo-controlled study. Nutrition Journal (2016).

• BOFF D. & al. Associated Strengthening Exercises to Undenatured Oral Type II Collagen (UC-II). A Randomised Study in Patients Suffering from Knee Osteoarthritis. Muscles, Ligaments & Tendons Journal (2020).

• HOPMAN M. & al. Efficacy of collagen supplementation on pain ratings in healthy subjects with self-reported knee pain: a randomised controlled trial. Applied Physiology, Nutrition and Metabolism (2020).

• JUTURU V. & al. UC-II Undenatured Type II Collagen for Knee Joint Flexibility: A Multicenter, Randomised, Double-Blind, Placebo-Controlled Clinical Study. Journal of Integrative and Complementary Medicine (2022).