Monday, 1 August 2011

Wine and Grapes Will NOT Prevent Sunburn

I was really disappointed to see this article written in The Telegraph, ' 'Drinking Wine Could Help To Stop Sunburn' this week. A really glaringly obvious example of really bad science and bad churnalism.

The article states, 'Drinking wine or eating grapes could protect you from sunburn, according to a new study that found a chemical in the fruit can limit cell damage.' Alongside this very appealing picture of a glass of wine in the sun. Nice, well then, let's all go outside and have a glass of wine in the sunshine and feel good about ourselves. Sound too good to be true? It probably is.



The article refers to a study published in Agricultural and Food Chemistry (not free access). The study tested some grape extracts (polyphenolic fractions, not wine) on some skin cells in a dish. They then exposed the cells to some UVA and UVB rays. They found that some of the extracts reduced the numbers of damaging reactive oxygen species (ROS) in the treated vs untreated cells. The concentrations of the extracts the study uses are fairly high (5-20ug/ml). The research paper discusses potential topical applications for these extracts (putting these concentrated extracts on your skin) NOT benefits from eating grapes or drinking wine.  Nowhere does the research paper state or allude to that drinking wine or eating grapes can help prevent sunburn, skin cancer or skin aging (which are other benefits of drinking wine/eating grapes that the Telegraph article mentions). I bet you all the wine I have in my fridge that the levels of extracts used in the study are not achievable by drinking your recommended daily wine allowance.

Onto the sunburn, I believe in my somewhat limited knowledge of sunburn (despite being a bit ginger and suffering from it a few times) that the vast majority of the 'burn' is caused by direct DNA damage by UVB rays. The study did not look at DNA damage/cell death, they only looked at some upstream cell signalling pathways and the amount of ROS. UVA rays, however, are thought to cause damage through activation of ROS, so this is a reasonable way of assessing the efficacy of certain compounds against UVA damage, but not UVB, which is what causes the 'burn' (someone correct me if I am wrong here). So the study wasn't even focused on compounds that prevent sunburn.

Continuing on the subject of sunburn, the study does not indicate what the level of UV radiation the cells are exposed to is comparable too. There is no measure to say that the UV rays the cells were exposed to are approximately equal to 1 hours sunbathing in a UV index of 8 or 36 hours in in the sun in the north of Scotland (or any other equivalent).  To be fair to the study, it is designed to compare the efficacy of different types of compounds rather than prove a direct link to preventing skin damage (although that is eluded to). The problem here is with the Telegraph article directly concluding that drinking wine could help prevent sunburn as found by this particular study.

My next issue is with the study itself. As a pharmacology PhD student, the importance of a vehicle control is drummed deep into my soul. Whenever you use a compound/extract/anything you need to dilute it in something else to get the desired concentration, this is the 'vehicle'. Standard practice in an experiment, you need to run a vehicle control to ensure that the thing you are diluting in isn’t causing the effect you are seeing in the experiment. This research paper HAS NO VEHICLE CONTROL. They only compare the effects to untreated cells, which are different (as they haven't been treated with the vehicle). Bad science.

I am surprised this article didn't generate more groaning and criticism. It has certainly created a storm of spin off stories on various news stories around the world. It also has made a lot of people happier about sipping a few glasses of wine on holiday... I have also drank wine in the sun, I still suffered from sunburn (actually more so as it caused me forget to reapply suncream as frequently!!). In conclusion, WINE AND GRAPES WILL NOT STOP YOU FROM GETTING SUNBURNT.

I have access to the journal, so I have read the paper, if you would like any more info, just let me know. Had some sucesses with getting the story changed (see below) but unfortunately the story is now all over the internet...!

Read Magdeline Lum's take on the chemistry of this research here - http://philosophicallydisturbed.wordpress.com/2011/08/02/red-wine-sunscreen/

EDIT 3.8.11 The Huffington Post changed their story in response to mine and Magdelines blogposts, http://www.huffingtonpost.com/2011/08/01/wine-sunburn_n_914955.html. Nice to know they are prepared to change a story.

EDIT 4.8.11 The Telegraph have now altered the story to reflect the study and removed the old story. Thanks to @TomChivers who helped get the story changed at The Telegraph.

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