Polyphenols and Sun Damage?

We all had a bit of surprise with the temperatures this bank holiday.  Here at Fivaday HQ a few of us were a little slow with the sunscreen, and we’re betting that some of you were too, but on the plus side it did remind us of another reason why we love polyphenol compounds.

As you will know by now, polyphenols are antioxidant molecules found in many foods such as green tea, chocolate, grape seeds, and wine. Polyphenols have antioxidant,anti-inflammatory, and antineoplastic properties. Growing evidence suggests that polyphenols may be used for the prevention of sunburns as they decrease the damaging effects of ultraviolet A (UVA) and ultraviolet B (UVB) radiation on the skin. 

What is sun burn?

By definition, it is easy to consider that it is actually the sun that burns the skin, resulting in the pain, heat and redness after being outside for too long, but the mechanism of sunburn is actually a little different.

It is an immune response.  

Melanin, a pigment in the skin absorbs UV light and dissipates it as heat.  Melanin is the natural sunscreen.  But when this defence is overwhelmed, a toxic reaction occurs, resulting in sunburn.  

When a UV photon strikes the skin, it can damage the DNA found in the cell.  When the body senses this damage, it kick-starts its trusty inflammatory response to fix it! Inflammation brings its signature moves; redness, heat and pain – blood flow to the area can support healing and pain keeps you from doing any more damage!  

But there is a fine balance, if cells are too damaged to fix, they are instructed to die, a process known as apoptosis – this mass death of cells results in whole layers of skin peeling off.  This needs to occur if they are to be replaced by new, healthy cells.  

But, this process, the exposure of skin to ultraviolet radiation, is known to stimulate the production of reactive oxygen species (this is what is thought to cause DNA damage), and as we know, the imbalance of reactive oxygen species to antioxidants results in oxidative stress.  

This is why polyphenols are thought to be protective in cases of sun damage.  

In one study,subjects between 18 and 50 years old applied various green tea extract concentrations on their skin.  This study showed that green tea polyphenol applied before UV exposure decreased sunburn cells by 66%.  

Other researchers studied the topical and oral use of green tea in 60 mice and development of skin tumours. Topical application of 3.6 mg green tea twice per week decreased skin tumours by 94%.

In another part of the experiment, mice were drinking water with gradually increasing green tea concentrations; they reached 100% green tea by day 6 and continued to drink 100% green tea for a total of 25 weeks. The number of skin tumours was significantly decreased at week 15 and week 25.  In experiments 1 and 2, the intensity and severity of sunburn lesions were significantly lower in groups pre-treated with green tea before UVB exposure compared to the control.

Grapes are widely available across the world and their seeds are rich in polyphenols, which allows them to have anti-inflammatory and antioxidant effects.  Researchers have established that pre-treatment with grapes resulted in a decrease in the number of sunburnt cells and DNA lesions.

Data Here

Whilst it is clear that there are significant benefits from topical application of polyphenols in UV exposures, there is increasing data suggesting a role for ingested polyphenol compounds in supporting our sun defence mechanisms, largely due to their capacity to re-balance the scales in oxidative stress!

The bottom line?

Include a range of polyphenols in your diet, and if you are looking for an additional antioxidant boost, maybe Fivaday can help?