The news of drinking wine as a preventative of sunburn is popping up all over the internet at the moment. I’m expecting it to see it soon in a local newspaper soon. The thing is, the news reports are too good to be true. The scientists behind the study never claimed any such thing and the most accurate reporting of it I’ve seen is on a European cosmetics design website and actually mentions the science.
There is an excellent blog post by Hapsci who dissects the journalism, (lack of), and explains what the researchers did and didn’t do. You should read it.
So what am I blogging about? The chemistry of course which in this instance will be forgotten in amongst the bad science reporting and outrage. It’s a pity really when people are worried about the presence of nanoparticles in sunscreens and sunblocks. There is research underway to study this as well as research into the behaviour of chemical compounds from nature that are able to block UV rays.
Marta Cascante, a biochemist at the University of Barcelona and director of the research project told The Telegraph in an interview,
“This study supports the idea of using these products to protect the skin from cell damage and death caused by solar radiation, as well as increasing our understanding of the mechanism by which they act.”
No mention of drinking red wine to prevent sunburn. Not one but there is mention of using a skin product to prevent sunburn, mentioned in the sentence immediately before.
The research was a collaboration between the University of Barcelona and the Spanish National Research Council and what was studied was a chemical reaction taking place on the surface of lab grown skin cells, (keratinocytes), when exposed to UVA and UVB rays from a lamp at a distance of 10cm.
And before I get to the guts of this post, I feel the need to point out that the research team did not even open a bottle of wine to do this study. To obtain the red wine chemical compounds to test for their sunblocking abilities, destemmed Vitis vinifera grapes were pressed and using column chromatography, the compounds in the juice were separated and collected. The chemical compounds being targeted were catechins and were categorised by the amount of polymerisation and galloylation, (presence of gallic acid within the compound). They were all sterilised before use.
Ok, now for the chemistry. Most of it you probably already know from the many years of health campaigns on skin cancer.
The effects of UVB and UVA radiation on the skin are burned, (excuse the pun), into Australians from birth. How does it happen though? UVA and UVB radiation is associated with generating reactive oxygen species like a super-oxide radical or hydrogen peroxide and usually these are dealt with by the body by antioxidants. What happens in periods of long exposure under the sun, (like when you spend a day at the beach), is that antioxidants in the skin can’t keep up with the incoming UVA and UVB radiation and the reactive oxygen species are able to oxidise molecules in the skin like lipids and DNA. The result is reddening of the skin and sunburn especially if you’ve forgotten to slap on sunscreen.
This is where the catechins come in. The researchers dosed the lab grown skin cells with the different types of catechins to see whether they were effective acting as sunblock. Catechins are known to be able to “scavenge” reactive oxygen species by reacting with them. It is this property that has led to research being done to test their antioxidant properties.
The Spanish researchers found that catechins which had a more polymerisation and galloylation were better at protecting the skin cells from damage caused by the UV radiation. They concluded that further research into the structures of the grape compounds is needed. It will be a while before anyone sees wine inspired sunscreen on the shelves.
And just in case it isn’t obvious enough…
Drinking wine will NOT prevent sunburn.
Reference: Cecilia Matito, Neus Agell, Susana Sanchez-Tena, Josep L. Torres, and Marta Cascante, Protective Effect of Structurally Diverse Grape Procyanidin Fractions against UV-Induced Cell Damage and Death, J. Agric. Food Chem., 2011, 59 (9), pp 4489–4495 DOI: 10.1021/jf103692a