COLLAGEN SUPPLEMENTS

The science behind the health benefits

Collagen supplements seem to be everywhere you look these days. The trend has been building for some years and the growth sees no signs of stopping with the global market for collagen supplements expected to reach over US$3 billion by 2027. But how much of this growth is hype and how much is supported by good science? The answer may surprise you.

COLLAGEN: FUNCTIONS AND STRUCTURE

Collagen is the most abundant protein in our body making up 30 percent of body protein. Its key role is as a major structural protein. You’ll find collagen in many tissues including tendons, ligaments, cartilage, blood vessels and skin.

Collagen has a triple helix arrangement of long chains of amino acids made up of repeating tripeptide units mostly of glycine (every third residue), proline and hydroxyproline. Hydroxyproline is unique to collagen as it is made from proline and requires vitamin C. The vitamin C deficiency disease of scurvy is a condition of very weak collagen.

Collagen though is not one molecule as there are 28 distinct types. But types I, II and III are the most abundant. Type I collagen is found in tendons, ligaments, corneas, bones and skin. Type III collagen usually is found along with type I collagen in the skin and blood vessels. Type II collagen is mostly found in cartilage.

Hydrolysed collagen dominates the supplement market. If native collagen is heated, it is denatured and this forms gelatin. But gelatin is not very soluble so hydrolysing collagen produces proteins of shorter lengths making them more soluble and absorbed quicker.

When collagen is consumed, it is digested and absorbed into the bloodstream where both single amino acids and unique dipeptides and tripeptides appear. These small peptides have a unique fingerprint because of the presence of the amino acid hydroxyproline. Remember: hydroxyproline is unique to collagen so these small peptide fragments can only exist in the blood from collagen breakdown or from collagen we consume.

Absorbed collagen peptides not only redistribute to the skin but can function as signalling molecules where they can bind to receptors on the surface of fibroblasts. Fibroblasts are skin cells that are major producers of collagen. The receptor binding stimulates fibroblasts to produce collagen along with elastin (for skin elasticity) and hyaluronic acid (for water retention). This is a crucial point as it explains a plausible mechanism whereby consuming collagen could have a direct effect on our skin.

Collagen Supplements And Skin Health

Degradation of collagen begins in our 20s and this is accelerated by sunlight exposure, smoking, environmental pollution, alcohol abuse and nutrient deficiencies. This leads to a volume reduction of the skin, loss of elasticity, decreased epidermal thickness, wrinkles and reduced capacity to retain moisture. The classic visual signs of ageing.

So, will taking collagen supplements support healthy skin? Over 20 randomised-controlled trials have explored this question and the answer is remarkably consistent: yes. A systematic review and meta-analysis published in the International Journal of Dermatology in 2021 looked at 19 of these trials. In all studies, both the participants and researchers assessing the effects were blinded to if a person was taking collagen or a placebo.

And the results of this systematic review were notable. Supplementation with hydrolysed collagen resulted in a significant effect on skin hydration, skin elasticity, skin density and wrinkles. And many of those clinical trials were independently funded with no commercial conflict of interest from the authors. Effective doses of collagen used in the trials ranged from 0.6 g to 12 g per day for 1 to 3 months. And not a single study reported an adverse event.

Other Benefits Of Collagen

Not all the research to do with collagen is about skin health. There have been several clinical trials looking at collagen and osteoarthritis with the combined research showing a clinically significant reduction in stiffness, pain and function.

Collagen makes up about three-quarters of the dry weight of tendons - making its use a popular choice by athletes for injury and exercise recovery. The small number of clinical trials in this area points to its benefit in soft tissue repair and improving exerciserelated joint pain and joint functionality.

There is also some interesting preliminary research showing that hydrolysed collagen may be effective at improving lipid metabolism, insulin sensitivity and hypertension in people with type 2 diabetes. So, watch this space as the research develops.

What It All Means

Most of the criticisms made about collagen supplements in the popular press are way off the mark and not reflective of the scientific evidence. There is good evidence that hydrolysed collagen improves many aspects of skin health in ageing with growing evidence for its use in osteoarthritis, sports injuries and exercise recovery. All for something that is naturally part of foods and has little evidence of any adverse problems.

Dr Tim Crowe

Tim is an Advanced Accredited Practising Dietitian, nutrition scientist and science communicator

Website: www.thinkingnutrition.com.au

Instagram: @doctimcrowe

Twitter: @CroweTim