DR MICHAEL MOSLEY: Incredible new health secrets linked to not being able to hold your drink or 'wine blush' - including the cancer you're more at risk of and what it means for your waistline

Heavy drinker or a bit of a lightweight (like me)? Blame your genes. A study published last week reveals how big an impact our genes have on our ability to tolerate alcohol, and why some people can drink so much more than others without, at least in the short term, feeling the effects.

Like most people in the UK, I have an alcoholic drink at least once a week, but for me it's very much a love-hate relationship.

While I've never been a big drinker — I flush and get migraines if I drink too much — I do enjoy the occasional glass of red wine with a meal, and sometimes more on an evening out.

These days, however, I become intoxicated faster and on less alcohol than I once did, and the hangovers are much, much worse. This is not surprising, as most of us become more sensitive to alcohol as we get older.

This is partly because our livers don't work as well as they used to, but also because we tend to lose muscle and put on more fat as we age. Fat, unlike muscle, is not so good at soaking up alcohol. But irrespective of age, why is it that some people are much better at handling alcohol?

Gender plays a part: men are normally able to drink more alcohol than women, mainly because we are bigger and tend to have more muscle. But much of it is also down to the luck of the genetic draw.

Compelling evidence for this has emerged from research by the University of California San Diego School of Medicine in America.

Researchers looked into this question by exploring data collected from more than 3 million people by genetics company 23andMe (one of the first commercial firms to analyse your DNA from a saliva sample and provide information about your genes, as well as your ancestors).

I had my DNA analysed and discovered that my ancestors are mainly European, with a touch of the Middle East. I also had a surprising amount of genes inherited from a distant Neanderthal ancestor (twice the normal levels, apparently), and some studies suggest that could be beneficial for my immune system.

As well as ancestry, you also learn a lot about your health, including whether you are more likely to put on weight or whether you have genes that make you particularly vulnerable to dementia (the answer, in my case, to both of those questions is 'no').

Of course, such analysis is not foolproof — we don't know all the genes linked to weight gain, for instance, and there is also the fact that how you live your life can change the ways your genes are expressed. Nonetheless, what the new study showed was that some people had a particular set of genes that meant that when they drank even a modest amount of alcohol they got lots of nasty side-effects, including nausea and flushing, the researchers wrote in eBioMedicine last month.

Normally, when you drink booze, the alcohol (or ethanol) in your drink gets converted by your body into a toxic substance called acetaldehyde. This, in turn, is converted into carbon dioxide and water, which exits your body via your breath or urine.

If you have genes that convert alcohol to acetaldehyde rapidly, or you lack genes that make an enzyme that breaks down acetaldehyde, you get a build-up of this toxic substance, and that quickly makes you feel ill if you drink a lot. Not surprisingly, people like me, who have these genes, tend to drink less than others because of the short-term, unpleasant effects.

According to this study, we don't tend to like whisky and are more prone to flushing and to 'wine headaches'. Because our genes mean we drink less, the researchers found we are less likely to have liver disease or depression; we also have lower blood pressure, less risk of heart disease and suffer fewer fractures than normal (probably because we don't fall over as much).

But it's not all good news. To their surprise, the researchers also found that people whose genes mean they can't tolerate alcohol have a higher risk of skin cancer, are more likely to be emotional eaters (when you eat as a way of helping you deal with your feelings, rather than just because you're hungry) and are also more likely to be short-sighted.

The researchers are currently trying to unravel these unlikely links.

As for me, for a long time I've tried to persuade myself that the upsides of drinking, such as being sociable and enjoying the temporary uplift in mood, outweighs the following downsides (grumpiness and headaches).

Then, a few months ago, I decided to try stopping drinking at all during the week.

I've found that resolution relatively easy to stick to, so I'm going to try to make it permanent. I'll let you know how I get on.

I am not great at small talk, so I sometimes struggle when talking to strangers. I also tend to avoid talking about subjects such as politics, with someone I've just met, in case things turn out badly.

But new research, published in the journal Psychological Science, suggests I'm being overly cautious and missing out as a result.

When volunteers were asked to discuss subjects such as abortion and climate change with people who held very different views, far from it being unpleasant, they said they found these conversations eye-opening.

And volunteers said they enjoyed being paired up with someone whose views they wildly disagreed with, which is heartening.

The 'unhealthy' foods I now wish I'd been eating for years 

At medical school in the 1980s we were taught that the main reason our patients were overweight and at risk of heart ­disease was because they were eating too much saturated fat (found in foods such as milk, cheese and butter).

One consultant told us 'eating saturated fat will clog arteries as surely as pouring lard down a drain will clog the sink'.

There have since been a mass of studies undermining this message — and yet it's still the advice you're likely to hear from the NHS.

We also used to be told to avoid cholesterol-rich foods such as eggs and limit them to no more than one a week. Supermarkets were soon stacked to the rafters with 'cholesterol-free' foods.

Yet it turns out this was nonsense and the effects of the cholesterol we eat on the levels in our blood is very small.

In a recent study (presented at the American College of Cardiology conference), people who were asked to eat 12 eggs a week for four months showed no measurable changes in their cholesterol levels when compared to those who only ate two eggs a week or fewer.

And it seems the dangers of cholesterol have been seriously exaggerated. For a long time we were told that because eating saturated fat increases levels of 'bad' or LDL cholesterol — which it does — then higher levels of LDL inevitably leads to heart disease. But that's not true.

A study, published in BMJ Open last month, which looked at data from more than 170,000 middle-aged patients, found that those with higher-than-recommended LDL levels were actually at lower risk of dying from heart attacks than those whose LDL levels were at or below the recommended levels. This is something that has been discovered in other research.

Rather than LDL, a better predictor of mortality is the ratio of total cholesterol to your HDL score. In fact, we need cholesterol to make hormones such as oestrogen and testosterone; it's also an essential part of your cell's membranes.

So these days I eat eggs most mornings. I also happily eat butter, full-fat Greek yoghurt and full-fat milk. I cook with olive oil and eat lots of oily fish.

I only wish I could go back in time and advise my younger self that decades of eating low-fat foods would not offer me any protection in later life.