We should limit our alcohol intake - but a little may be good for us. Michael Mosley investigates the confusion over what we should - or shouldn't be drinking.

You can't open a newspaper without reading a story about a glass of wine being good or bad for you, or making no difference at all.

As a regular, albeit modest drinker, I wanted to find out what the latest research says.

The government recommends men drink no more than three to four units a day, women no more than two to three - and you should have two days off if you're drinking too much.

At medical school I was taught about the 'U' or 'J' shaped curve which argues that a little bit of alcohol is good for you. So is it true?

Well, if you like a drink, there is some good news but it might not be in the quantities you would hope.

One of the downsides of drinking alcohol is the increased risk of liver disease and cancer. The upside is possible protection against heart disease.

Dr Peter Scarborough from Oxford University says the downside swiftly displaces the upside, and that half a unit (about a quarter of a glass of wine) is the optimum amount you can drink in a day.

He adds: "If you're drinking any more than that then you are not at the best level for reduced risk."

'Jury still out'

Sir Ian Gilmore, a former president of the Royal College of Physicians, believes the evidence still isn't clear.

"I think it's fair to say the jury's still out. There certainly isn't enough evidence to say people that don't drink should start drinking because of their health."

Henry Ashworth, from the Portman Group which represents UK drinks producers, says that most of us are drinking within the limits, and supports the government's advice.

I can think of a time in 10 years when you might go into a pub or club and put a pound and your finger into a machine to tell you what your risks are Sir Liam Donaldson,, Former chief medical officer

"Guidelines are hugely important because we want to have more informed consumers.

"It's really important they stay consistent because the last thing you want to be doing is chopping and changing so people get confused."

The other part of the Government advice is that you should have two days without alcohol after a heavy session to let your body recover.

But Dr Nick Sheron, a liver specialist at the University of Southampton, says that this is nothing to do with giving your liver time to recover, but all about dependency.

"What is clear is that if you are dependent on alcohol then cutting it out two or three days a week is going to be very difficult, and actually it's a real warning sign that you are somewhere on the dependency scale."

Genetic limit

I found that most of the people I spoke to couldn't tell me exactly what an alcohol unit was. The whole message seems confused.

Sir Liam Donaldson, a former chief medical officer to the government, says using units as a measure of alcohol intake was something he was planning on changing before he left the post in 2010.

"Compared to some of the other health messages like don't smoke or eat five-a-day, following the healthy alcohol guidelines is not an easy thing for people to hold in their minds when they are going out to a bar or the pub."

Developments in science may add to the confusion.

What each of us can drink safely is partly dependent on our genetics, and Sir Ian Gilmore says that in the next decade we could have personally-tailored advice on alcohol consumption.

"We know there's a big genetic element to alcohol dependence. We know that it runs in families and twin studies have shown that very clearly.

"I can think of a time in 10 years when you might go into a pub or club and put a pound and your finger into a machine to tell you what your risks are."

Sir Liam agrees genetic studies may change things.

"I think the whole classification of disease might change as a result of starting to think about physiological processes that have been mapped out by genetics.

"So you may find that you're a drinker who is 10 times more likely to get liver cancer or liver cirrhosis compared to somebody else drinking at the same level because you have a genetic susceptibility - that at the moment we can't determine.

"In 10 or 15 years' time I'm sure we'll be able to."

'Smaller glasses'

The Department of Health says: "The health risks from alcohol rise as you drink more and there is some evidence that small amounts of alcohol can reduce some health risks.

"To look at whether the system is still helpful to people, the chief medical officer is set to review the alcohol consumption guidelines."

I think the guidelines around alcohol are well-meant but confusing, at least in part because no-one really understands units.

So, if I had my way, I'd go for something much simpler. A "two two" campaign - two glasses of alcohol a day, maximum, and two days off a week.

I would also encourage people to buy smaller glasses.

You can listen to Dr Michael Mosley on BBC Radio 4's You & Yours on 4 January at 12:00.