Science Interviews

Interview

Sun, 7th Jan 2007

The Wine Diet: Is Red Wine Good For You?

Roger Corder, from the Royal London School of Medicine

Part of the show Red Wine, Caffeine and Bugs in Your Gut

Chris - One of the things you've risen to prominence for Roger is sussing out what's in red wine that makes it good for us.

Roger - Absolutely, that's been my work for the past six or seven years. I've focused on finding out what is in wine that improves blood vessel function and protects from heart disease.

Chris - So how did you go about that and what is the bottom line? Is it good for us?

Roger - All the evidence points to it being good for us. But it may be that certain types of wine are much better than other wines. What we did from a laboratory point of view is we studied exactly what substances in wine could change blood vessel function. In parallel with that we were looking at areas where people were living longer and drinking wine. And we saw that the wines in these areas were richer in a substance we identified, procyanidin, which is a flavanoid polyphenol. People would know them as anti-oxidants but in terms of the effects that we were looking at, this causes a profound change in blood vessel function.

Chris - There is a phenomenon called the Mediterranean Effect isn't there for people from the Mediterranean basin. And the French paradox as well. There are French people who manage to have an atrocious diet, smoke like chimneys, and live to be 500 years old. No one really understood how they did it, and what you're saying is that it's the red wine that they're drinking.

Roger - Exactly. The Mediterranean diet sprung out of research called the seven country study. That showed that people living on the island of Crete were living longer with less heart disease despite a fairly high fat diet. But an important part of their diet was to drink regular wine. Now I started to look at Sardinia because the highest concentration of centenarians were based on this island in terms of European population, and I found that their wines were richer in Procyanidins than wines from other areas. The Cretan wines were also particularly rich in this particular polyphenol. And so I then looked at the French population. And there's a regional variation in heart disease across France. And there's also a regional variation in terms of longevity. And what I found was that people living in South West France were drinking wines which were very rich in these polyphenols. But the interesting thing about this and the French paradox, is that this is one of the areas of France where they eat some of the fattiest foods. And so I became convinced that a) Wine should be part of a healthy diet, and b) some of the nutritional advice being pushed on the general public was actually not based on fact.

Chris - Is there a conflict of interest here Roger, because you're a wine connoisseur aren't you?

Roger - I wouldn't like to say I'm a wine connoisseur. Obviously we all like to have excuses for our habits. What I was, was somebody who was religiously following a low fat diet. And I suddenly started looking at the science of low fat diets, and realised that actually, if you wanted to have a healthy cholesterol level, it was the type of fats you ate, rather than having a low fat diet. Low fat diets are often boosting over-purified carbohydrates into people's food, and sugar into people's food. And that was actually changing their heart disease risk in an unfavorable way. And so this drove me to write a book to explain what it is about eating healthily that everybody should understand. It doesn't matter whether you're thin or fat. Wine can be part of it, but the food you eat is so crucial to your overall wellbeing.

Chris - Let's just focus in on the wine story for a second. You saw this effect, which was distributed across France, and the effect rose specifically in South West France. So what was going on there that meant that people, despite an atrocious diet, were protected? Presumably it wasn't just genetic.

Roger - I wouldn't say their diet was atrocious, it was just different. Essentially they were growing a grape down there called the Tannat grape that was very very rich in these protective polyphenols. But other wines are also good for you.

Chris - Is it just red wine though Roger? Because lots of people say you have to drink red wine, white wine's no good. Beer's no good.

Roger - Well, let me provide you with some evidence. Alsace has the lowest longevity in France. And it has some of the highest heart disease. That's a white wine drinking area.

Chris - So it is specific to the colour. Red wine grapes impart the protective chemicals.

Roger - Exactly.

Chris - What are those chemicals, how do they work and how does the grape make them?

Roger - Actually white grapes also have them. The difference between white wine and red wine is really the way in which the wines are made. The white wine is the fermented juice of the grape, where red wine is the fermented juice with the seeds and skin present. So the longer the time of the fermentation with the seeds, the more extraction of these polyphenols that you have. And so the higher the levels.

Chris - Ok so we know wine has this stuff in it. How do we actually get this stuff to where it needs to go, the blood vessels? Why does if affect your risk of vascular disease? How does it work?

Roger - Essentially, if you imagine that blood vessels are a tube, and they have a lining which is protective. It's important that they function in a healthy way. Now the chemicals in wine are able to boost the healthy characteristics of this lining. So that you reduce your risk of heart disease. Many people may be aware that chocolate has also been said to be helpful. Now the point about chocolate is that dark chocolate has the same polyphenols in, as a good red wine. As so for non wine drinkers, if they want to get these polyphenols into their diet from other sources then dark chocolate becomes a possibility.

Helen - So I bet people out there are dying to know. Can we say in a snapshot, what should people be eating? And how many glasses of red wine should I be drinking? Is there enough in one glass?

Roger - If you look at a glass of average supermarket wine there isn't probably enough to have much benefit. But with time we're going to change people's awareness of wine and also the way that it's labeled. If there was more details about the wine making process, one could read the label and think that if it's been fermented a long time it's much more likely to have a higher level of these compounds. But there's no information on wine. How much should you drink? All the scientific evidence about reduced heart disease actually reflects a consumption level that is similar to what government guidelines recommend. So for a woman that's no more than one to two small glasses per day, 125 mL. For a man, two to three glasses is ok. But an important factor about people benefiting from wine consumption is that it's part of a lifestyle pattern. It's not going to the pub and shoving down a few glasses of wine and then thinking, "I've got all the benefits". Because studies have shown that people who drink without food are more likely to have high blood pressure. High blood pressure increases your risk of heart disease and it increases the risk of a stroke. So it's important to understand fully, the lifestyle combinations.

See also Roger Corder's book "The Wine Diet", which will point you in the direction of the healthiest red wines to have at dinner time.

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