collagen: 21 forever ?
Collagen is the most abundant type of protein in humans, ~30% of it being spread around the body. Its dietary sources include meat, fish and shellfish, bone broth and egg whites. Vegan collagen can be synthesised from genetically modified bacteria and yeast.
The 3 most common (out of 29) types of collagen are:
Type I - teeth, bones, skin, ligaments & tendons
Type II - eyes & cartilage
Type III - blood vessels, skin & muscles
As we age, our collagen stores decrease, which provides the perfect opportunity for collagen supplement companies to sell us the idea of the fountain of youth / beauty elixir. Claimed benefits include skin youthfulness, hair & nail strength, joint and bone health,
Theoretically, it all sounds legit. Collagen makes up ~75% of the skin’s dry weight and Type I collagen provides the skin its youthful elasticity, hydration and strength. Wrinkles become more defined as these features are lost with age. Collagen supplements should solve this, right? Not quite.
Existing evidence supporting such claims is weak, as the studies are small and often funded by collagen producing companies. Within 15min of research, I found 8 randomised controlled trials (what is meant to be high quality research) that reported no conflict of interest, although after digging deeper, they were all related to supplement/beauty companies all over the world.
Besides conflict of interest, there is no strong evidence partially because of the way collagen is metabolised. As it is a type pf protein, like all proteins, it is broken down into amino acids when ingested. It then ends up in the common “amino acid pool”, from where amino acids are drawn and converted back to proteins for various physiological functions.
In other words, the body does not decide that collagen goes to the skin, hair or nails, but rather, it is converted to the type of protein the body needs at the time. Also, the body can make collagen out of the amino acid pool, even if collagen is not obtained from the diet.
Although collagen supplements are often in the form of hydrolysed collagen or collagen peptides, which are partially broken down and therefore, are more readily available to the body, it still does not mean that all of it goes to where it is desired.
So although the current evidence is too weak for skin-related health claims to be approved, hopefully some larger, placebo controlled RCTs will be carried out in the near future. In the meantime, be aware of the current lack of research when a wellness influencer tries to sell you their supplement.
Lastly, it is important to keep in mind that collagen synthesis can be stimulated by retinol and other vitamin A derivatives, as well as vitamins B3, C and E. On the other hand, the sun damages collagen structures. So overall, there are other ways of stimulating collagen production than taking collagen itself.
