Bubbles go Straight to your Head

米拉welc——想打开一些香槟ome in the New Year? It may be worth you noting that the bubbles that make this drink go pop when you open it will get you drunk a lot faster than its wine relatives. I'm with Fran Ridout, clinical research manager for the charity Saving Faces at St Bartholomew's hospital in London. Fran used to be based at the University of Surrey where she looked into the effects that champagne has on our brains. How did you go about looking into the effect of champagne?

Fran - We used a psychometric test battery which measured people's reaction time, ability to attend to a stimulus while doing something else, their vigilance, their ability to do something for a sustained time and their short-term memory.

Meera - Who did you test it on and how did you go about getting your samples?

Fran - We actually did the tests on volunteers' work colleagues. We had 12 people and they had two different drinks. One of the drinks was ordinary champagne and the other drink was champagne where we'd whisked all the bubbles away from with an electric blender. We had people drink both drinks on different occasions a week apart. One week they'd have champagne with bubbles, the next week they would have the champagne without bubbles which they thought was ordinary wine. They didn't know the purpose of the experiments. Everybody did a baseline test before they'd been drinking. They then drank a measured dose of the champagne or de-gassed champagne according to their body weight. Then they did the tests again 20 minutes after and 60 minutes after drinking.

Meera - What did you find?

Fran - We found that the champagne with bubbles was much more impairing than the champagne without. We found a difference on all the tests between when they did it before they'd drunk anything and afterwards, apart from short-term memory. With the sill champagne the only test that was impaired was a simple test of reaction time.

Meera - You also looked into the actual blood levels of alcohol in the people.

Fran - Yes, we took blood samples after twenty minutes at five minute intervals. We found that the blood alcohol levels of the people drinking the gas champagne were higher for the first twenty minutes suggesting that it had got into the blood stream a lot quicker.

Meera - You've actually got some of these psychometric tests set up today. I had a go on two of them earlier this afternoon just to give an idea and get the score for what's my ability without alcohol. I'm just going to finish off this champagne and then we're going to have a go on the tests and see if it's impaired my ability at all.

Fran - An excellent idea!

Meera - Well we actually have two of those psychometric tests. What am I supposed to be doing here again?

Fran - The idea is to keep the centre of the cross on top of the ball as the ball moves randomly from side to side across a screen. The other part of the test is that you have to watch out for yellow balls which will appear in corners every now and then. As soon as you see those you have to click the button on your mouse.

米拉-好的,我又有一个继续这个测试了now and trying to follow this grey ball that's moving around with my green cross. That one's finished. You've got both of my scores up here. Is there a difference between before and after I drank this champagne?

Fran - There are differences between your tracking. You've actually got better but that is a practise effect. When we did our study we made volunteers do it half a dozen times before they started to get rid of that as far as possible. One component of the test is your ability to react to peripheral stimuli: the yellow balls. Your time there is actually longer.

Meera - We've also got this second test set up which is going to test my movement. I'm just going to start this now but can you just remind me again what the rules are?

Fran - This tests reaction times in two parts. There is a semicircle of lights which come on and you have to move your finger as quickly as possible from across a resting point to turn those lights off. It has two components. One is how quickly you lift your finger up to say I've seen the light and the other is how quickly you can get your finger over to put the light out.

Meera - That's finished now and all the lights have come on so I think I'm going to stop. How did I do here, Fran?

Fran - Well you didn't do particularly well. Your reaction time for the lights was nearly 100ms slower. Your score at baseline was 362 and after you'd had your drink it was 452ms. 100ms may not sound much but if you're driving a car it's extra time it takes before you put your feet on the brake. You could have gone quite a few metres down the road in addition to your normal brake time.

Meera - I guess the key question now really is why this happens. Why does the presence of bubbles in alcohol make it affect our brains quicker?

Fran - In order to affect the brain it's necessary for the alcohol to get into the blood stream. The way this happens is you drink the alcohol which goes into your stomach. Not much of it's actually absorbed in the stomach. About 80% of it is absorbed when it carried on into the intestine. The most likely explanation for the champagne having a more intoxicating effect is that it alters gastric emptying - the way that the alcohol or drink goes from the stomach to the intestine in some way. One possible mechanism is that it alters the way that the pyloric valve opens or makes it open more frequently. That's the part that allows the contents of the stomach to carry on its way to the intestine. Alternatively it could be that the alcohol is absorbed as you're drinking it through the nose, through the mouth. That's much less likely. It's almost certainly something that happens once the alcohol gets into your stomach.