Tuesday, August 19, 2014

Ten things your doctor won’t tell you about wine and health

A recent column in MarketWatch called “10 things your winemaker won’t tell you” has provoked considerable controversy, and the way I see it the statements about wine and health are particularly off base. So my response is a list of what your doctor probably won’t tell you; part of this will refute the MarketWatch piece, part of it will get at the misconceptions that underlie the problem. Author Catey Hill does make some interesting and valid points, but the question of healthy drinking is just too big to be distilled into a paragraph or two. I do know this though: it isn’t the winemaker’s job to tell you about its health benefits, and in fact the feds take a pretty dim view of that idea.

       1.       Hill states “Scan any health website these days and you’re likely to find at least one article touting the health benefits of wine, among them heart health and longevity—all the more so since the recent discovery of the antioxidant resveratrol in red wine. But some studies suggest there are more risks to wine consumption—or at least fewer rewards—than recent headlines might suggest. ” We must first point out that the discovery of resveratrol is not especially recent; a PubMed search returns nearly 6,700 articles in the biomedical literature on resveratrol, hardly qualifying it as an incompletely studied novelty. The issue is whether resveratrol is actually the reason for wine’s health benefits. Evidence seems to point elsewhere, given the low amounts of resveratrol in wine or any other dietary source. Resveratrol is clearly not “all the benefits of wine without the alcohol” as touted in supplement ads.
2.       Despite this understanding that researchers familiar with wine and health have had for years, the fallacy repeated in Hill’s article (and many others) is equating resveratrol and wine as the same thing. She cites an article much ballyhooed this year in the Journal of the American Medical Association in which researchers tracked a population of men over nine years, measuring resveratrol levels in their urine as a marker for dietary resveratrol intake. The more wine and vegetables in the diet, the hypothesis went, the more resveratrol and therefore lower mortality and disease. The lack of any correlation was interpreted as meaning that wine wasn’t so good after all, despite the fact that those in the know had abandoned the idea years before the study was completed.
3.       So how did the claims to health and longevity get started in the first place? What it boils down to is this: moderate wine drinkers live longer on average than nondrinkers, they have lower rates of degenerative diseases such as diabetes, osteoporosis, and cancer; and they have higher quality of life by standard measures. Statistically, it doesn’t matter whether it is the resveratrol, the alcohol, or anything else. Individual studies looking at individual disease conditions can therefore give a false view of the bigger issue. An example of this is another study (albeit a large one) cited by Hill, which showed that alcohol consumption even in moderation was associated with an increased risk of atrial fibrillation, a marker for heart disease. But the preponderance of data, from even larger studies such as Framingham, indicates that moderate wine consumption is the single lifestyle factor most protective against heart disease other than not smoking.
4.       Red wine drinking makes for healthy teeth. On the other hand, white wine may erode tooth enamel, according to an article cited by Hill. But the polyphenols in red wine – the things that make red wine red – are potent inhibitors of the bacteria that cause plaque and cavities.
5.       What your doctor really doesn’t want to tell you is that they don’t trust you to understand what moderate drinking is. Hill cites physician and author John La Puma, who points out (correctly) that the standard measure of a glass of wine on medical studies is 5 ounces, yet most wine glasses hold more. This leads to what is known as the under-reporting bias, meaning that people drink more than they think they do (or report that they do.) But the logical conclusion of this is that wine is actually better for you than we thought; if the healthiest level of drinking (lowest point on the J-shaped curve) is two 5 ounce glasses, what that really means that it is more, because the data is based on self-reporting.
6.       Alcohol is part of the health benefit equation. Claims that you get the same benefits from grape juice are dubious, and there are several reasons why it would be so: For starters, grape juice is full of sugar, and alcohol calories are metabolized in less deleterious ways. Perhaps more importantly though, the polyphenols in the skin of the grape occur in higher concentrations in wine grapes, and are extracted and concentrated during fermentation. But alcohol in the right amounts has specific health-promoting properties, which I outline in a chapter in my book.
7.       Sulfites in wine are not the reason for allergic reactions. Hill mentions sulfites only in passing, but it is commonly believed that flushing and other symptoms relate to the sulfites in wine that are added as preservatives. But they occur naturally, and when added are still in much lower concentrations than many common foods such as dried fruit. The reactions are usually attributable to histamine-like compounds that develop during malolactic fermentation, a type of secondary fermentation mediated by bacteria rather than yeast.
8.       Wine is more than heart healthy. Because the French paradox highlighted cardiovascular disease, early research focused on that. But as knowledge of wine chemistry expanded, research extended into several areas of anti-aging health issues. But focusing on only one condition (for example atrial fibrillation in the article referenced above) can obscure the larger benefit across a range of benefits to health and longevity.
9.       Wine is good for the brain. Every major epidemiologic study of Alzheimer’s disease and age-related cognitive decline has found a strong correlation of moderate wine consumption with higher mental function during aging. [references in my book]
10.   Research on wine and health is comprehensive. A recent summary called “Mapping the scientific research on wine and health” noted that the field is highly interdisciplinary, with publications in more than 500 different scientific and biomedical journals. There are few if any aspects of health research more thoroughly investigated.