Monday, January 23, 2012

Is alcohol necessary for wine’s health benefits?

High on the list of controversies about wine and health is the alcohol question, one I get asked about every time I do a seminar on the subject. Why not grape juice, or for that matter wine's goodness in a pill?
New research from the University of Barcelona took the question head on and it's good news for wine drinkers.

There are so many thousands of papers on wine and health now that you can be forgiven for not keeping up (which I am taking care of for you here) but in order to understand the implications of this latest study we need a little background. For one, as I said in the book, wine is not just grape juice without the alcohol; the content of polyphenols antioxidants is much higher in wine for several reasons (for another, grape juice is high in sugar.) There is a great temptation to assume that we could just take the polyphenols from grapes and put them into supplement form, which indeed many have. For non drinkers and occasions where wine consumption is inappropriate, it may not be such a bad idea. But does alcohol make a positive, independent contribution to health?

In terms of cardiovascular health, it is known that alcohol in moderation improves the HDL/LDL cholesterol ratio, and it is tempting to assume that is the end of the story. But atherosclerosis is a much more complex phenomenon than simply sludged up pipes from a high fat diet. Chronic inflammation, at least as biologists use the term, is the important underlying factor. So the scientists in Spain designed a clever clinical study in which volunteers were assigned to three groups: one consumed a standardized amount of red wine daily, another an equivalent amount of de-alcoholized wine, and a third had gin, standardized to the same alcohol amount as the wine group, for 4 weeks. They then measured 25 separate inflammatory biomarker levels. These molecules go by an alphabet soup of names, but the implications of the study were clear: Both alcohol and red wine polyphenols independently improved (“down-regulated”) inflammatory marker levels, and though there was some overlap they generally worked differently.

So is alcohol an anti-inflammatory compound? At least where cardiovascular disease is concerned, it would appear so. That would explain why alcohol from any source appears to offer some benefit, though not as much as when it is in wine. Another important aspect of this study is that it is a randomized prospective clinical trial, meaning we can take very high-level confidence in the results. Not that I had any real doubts.

Tuesday, January 10, 2012

New evidence that red wine lowers risk of breast cancer

Does drinking red wine increase risk of breast cancer? If you have been following the news over the past few years, you might have a hard time justifying that glass of wine with dinner, as we are told that even in moderation the risk of breast cancer increases. But as I have said here before (see post from Nov 2 2011), the whole topic is widely misunderstood and oversimplified, despite the declarations of medical authorities. But a new study helps to shed some light on the subject.

So why is the party line so negative on wine? At first glance, the evidence seems overwhelming: dozens of studies showing that consumption of alcohol in any form – red or white wine, beer, spirits – increases chances of developing breast cancer by about 10% per drink per day. Some of these studies are quite large, with thousands of women surveyed. A closer analysis reveals some serious problems however. To begin with, any time there are dozens of population studies all looking at the same question, we may fairly ask why the question is so difficult to answer. A quick glance reveals one obvious problem: not all the studies find an association of alcohol consumption with breast cancer. Another, more pernicious problem, has to do with a fundamental weakness of population studies: they rely on self reporting, which in the case of alcohol consumption is notoriously unreliable. The result is that heavy drinkers are misclassified as moderate drinkers, suggesting that low levels of drinking are unsafe.

More to the point is the fundamental question of whether red wine is different in terms of risk than other alcoholic drinks. Since women in the U.S. and Britain tend to have mixed drinking patterns – for example, minimal drinking during the week, and a variety of different drinks when they do – it becomes impossible for all practical purposes to know what the effect of regular, moderate consumption of red wine would be. 

It is also difficult to pin down exactly what alcohol does to increase breast cancer risk, but the theory seems to be that it promotes estrogen and so it is primarily estrogen-dependent tumors that account for most of the problem. This latest study attempted to address that by evaluating the effect of compounds in red wine that inhibit an enzyme called aromatase, which converts testosterone into estrogen. Using what is called a crossover prospective trial, they were able to show that consumption of red wine in volunteers had a positive effect, concluding that “red wine is a nutritional [aromatase inhibitor] and may explain the observation that red wine does not appear to increase breast cancer risk.” (emphasis added). So enjoy a glass of red wine with dinner and enjoy life.