Collagen supplements: Can you eat yourself pretty?

By Niki Bezzant

Google 'collagen' and you'll be served up a buffet of products: Tablets, powders, gummies, shots, liquids and bars.

Some are promoted for skin, hair and nails; others for joints, bones and ligaments. The promises are varied, ranging from glowing skin to less cellulite. One product has its boldest claim right in the name: Age Reverse.

It seems every wellness influencer from the Kardashians on down has their favourite collagen potion to push.

Is there any truth behind the marketing spiels of these popular supplements? Can they help us appear more youthful, have shiny hair and healthy nails and limber joints? Let's break it down.

What is collagen?

Collagen is an essential and abundant protein in our bodies; one of the major structural proteins we need to keep our skin, bones, cartilage, tendons, nails and hair healthy.

Our bodies contain 28 different kinds of collagen and they naturally produce collagen from foods we eat. Just like in humans, collagen is in the connective tissue of animals, so animal protein foods like chicken, meat and fish are good sources.

What does collagen do?

In our skin, collagen works like a structural girder alongside hyaluronic acid and elastin to maintain elasticity, volume and moisture.

We lose collagen naturally - and some of our ability to produce it - as we age; it's part of the ageing process, and is exacerbated by the hormonal change of menopause in women. Loss of collagen is partly why we start to see signs of ageing in our faces, such as wrinkles and sagging of the skin.

Lifestyle factors - things like smoking, a high-sugar diet and alcohol consumption - also lower collagen production; as with most areas of health, how we live impacts us here.

And in Aotearoa, the impact of sun exposure throughout our lives also affects our collagen production in the skin, and this really comes to the fore as we get older.

In our joints, collagen helps keep cartilage strong, protecting the joints from wear and tear. It's an important component of muscle. And in bones, collagen helps maintain strength and structure. We experience loss of collagen here, too, as we age.

How do we produce collagen?

When we eat protein foods, including foods containing collagen, that protein is broken down in the body into peptides. We can't actually absorb collagen in its whole form.

These peptides are then further broken down into amino acids, the building blocks of protein, which go on to be used as they're most needed, which might be anywhere in the body. Some of these might form collagen.

But - as nutritionist Nikki Hart points out - "the body will prioritise where that collagen goes". That means it's equally as likely to go to the joints, bones, or cartilage as it is to the skin.

"You don't have control over how the collagen is used," Hart says.

Dermatologist Sonya Havill agrees.

"If you eat chicken bones with that collagen bit over the end of the drumstick, say, it doesn't mean that you're going to get better collagen in your knees or in your face. That's not how it works."

Collagen supplements are generally hydrolysed, which means the collagen has been processed and broken down already into peptides; the thinking being it's more easily absorbed that way. Collagen supplements can contain collagen from different animal sources including beef, pork, chicken and fish (marine collagen). Sorry vegans, there's no animal-free collagen supplement.

What's the evidence on collagen supplements?

Collagen supplements have many fans, but it's fair to say the evidence is mixed, and far from overwhelmingly positive, on whether or not they actually work.

There are some studies showing collagen supplements have some benefits to skin in terms of moisture content, elasticity and wrinkles. It's worth noting most are small studies, and it's not clear the skin improvements are directly as a result of collagen, or if they could be down to other ingredients in the supplements being tested. Also worth noting: some research is sponsored by the companies who make the supplements.

There's some evidence to show collagen supplements might help with joint pain and stiffness. It's not really clear why this would be yet - the experts say more research is needed.

And there's an interesting (again, small) study showing a supplement of collagen, vitamin D and calcium helped prevent bone loss in women at risk of osteoporosis. Again, more human studies are needed to confirm this.

There's only very scant evidence that collagen helps with nail health. A Harvard Medical School on collagen notes there haven't been any studies in humans looking at the benefits of collagen supplements for hair, so take those claims about luscious locks with a pinch of salt.

As the experts note, taking a supplement marketed at a particular body part is no guarantee that's the result you'll get.

"You might be taking the collagen and you think it's for your skin," Hart says. "But it goes into the amino acid pool [in your body] and it goes where it wants to go."

Are there other things we can do to boost our collagen?

Yes, there are. When it comes to the skin, they're "all the things that no one wants to know about," according to Havill: regular exercise, a good healthy diet, not smoking or drinking too much alcohol and reducing stress.

"If your general health is poor, then your skin is going to be in bad condition. So generally that things that improve your general health, like exercise and a good diet, are going to improve your facial skin."

Also: be diligent with the sunblock, have a good intake of protein foods, and don't forget the vitamin C-containing foods, too.

Hart's preferred way of getting her collagen in is in the form of bone broth. She reckons half a cup with a bit of ginger in it is delicious, "and that's giving you six grams of protein, five grams of collagen".

"There is less chance of toxicity and it's safe. So if you want to do it, do it that way."