Sun and collagen: How UV radiation causes the skin to age – and what protects it from within

The sun is the most significant factor in the ageing of our skin – more so than our genes, and more so than the passage of time itself. In a widely acclaimed analysis by Flament et al. (2013) could amount to around 80 % of visible facial ageing can be attributed to sun exposure. Fine lines, age spots, a leathery texture: many of the changes we consider to be part of normal ageing are in fact caused by sun damage – and are therefore largely preventable.

Photoageing – when light causes the skin to age

The technical term for light-induced skin ageing is „photoageing“. It describes a different process from purely time-related, ‘internal’ ageing. The reasons why the skin ages in general are explained in the article Why does our skin age? as described – the sun actually accelerates this very process. UV radiation penetrates the skin and sets off a chain reaction which ultimately leads to the breakdown of collagen: the structural protein that keeps the skin firm and elastic.

The mechanism – MMPs break down collagen

When UV radiation hits the skin, it activates, amongst other things, enzymes known as matrix metalloproteinases, or MMPs. These MMPs break down the collagen and elastin fibres in the dermis, the middle layer of the skin. At the same time, free radicals are produced – oxidative stress – which cause further damage to the fibres and inhibit the fibroblasts, i.e. the cells that produce new collagen. Over the years, this takes its toll: more collagen is broken down than is replaced. The result is visible in the form of wrinkles, a loss of firmness and uneven pigmentation.

UVA and UVB – two types of radiation, two effects

Sunlight contains two types of UV radiation that are relevant to the skin and have different effects. UVA radiation has a longer wavelength, penetrates deep into the dermis and is considered the main factor in light-induced skin ageing. It is present all year round and even penetrates window glass. UVB radiation It acts more superficially in the epidermis and is primarily responsible for sunburn; its intensity varies more significantly depending on the time of year and time of day. Both factors contribute to skin ageing – which is why protection should always be „broad-spectrum“.

External protection – the non-negotiable standard

The most effective protection against photoageing is unspectacular yet unbeatable: preventing the sun’s rays from reaching the skin in the first place. This includes daily sun protection with a sufficient sun protection factor (SPF), protection from clothing and a hat, and seeking shade during the midday sun. No nutrient and no supplement can replace these basics – that is the most honest statement in this text and the yardstick against which everything else must be measured.

Protection from within – what antioxidants do

In addition – not instead – diet can play a part. The idea behind this is that antioxidants neutralise some of the free radicals caused by UV radiation, thereby reducing oxidative stress from within. Stahl & Sies (2012) showed that dietary carotenoids can contribute to measurable, albeit moderate, UV protection from within. A review article by Pilkington et al. (2011) takes a sober view of diet and photoprotection: nutrients such as carotenoids, vitamin C and polyphenols can support the skin’s own defences, but provide only a fraction of the protection offered by sunscreen.

• Carotenoids (such as beta-carotene, lycopene and lutein from tomatoes, carrots and green vegetables): help protect cells against UV stress.
• Vitamin C: An antioxidant and, at the same time, a co-factor in the body’s own collagen synthesis.
• Polyphenols (such as those found in berries and green tea): help to reduce oxidative stress in the skin.

Put in the right order – the order matters

If we summarise the evidence objectively, a clear hierarchy emerges: internal protection is a sensible addition, but never a substitute for sun protection with SPF. Anyone who relies on an „internal UV protection“ supplement and skips the sun cream is making exactly the wrong choice. The sensible approach is the reverse: first, consistent external protection – ideally applied thoroughly to the Morning routine established – followed by an antioxidant-rich diet to reinforce this. And as with all Anti-ageing myths The fact is: there is no miracle cure, only the consistent combination of small, evidence-based measures.

Anyone wishing to specifically boost their antioxidant intake can do so by using nutrients that the skin needs anyway. Vitamin C is particularly useful here – both as an antioxidant and as a building block for collagen formation. In the Liquid Collagen Pro Active Advanced It is combined with hydrolysed collagen peptides: a way of supporting your skin from within, which complements a healthy diet but is by no means a substitute for sun protection.

Up to 80 % of visible skin ageing is caused by the sun – so the best anti-ageing measure is to stay in the shade and use SPF. What comes from within enhances this protection, but can never replace it.