New research: Wine allergies exist. You probably don’t have them.

A lot of people seem to think that they’re allergic to wine. Most probably aren’t. Our current best evidence on sulfites says that only people with severe asthma have any real cause to worry and, given the presence of sulfites in many other common foods – most dried fruit, many cured meats, salad bars – it’s something they surely know before ever meeting their first glass of wine. I’m one of a subset of people who react dramatically to biogenic amines, molecules produced by some yeast and bacteria that mimic human hormones and cause me to go hot and red in the face and sprout a bad headache after only a few sips of an affected wine (embarrassing when people think I’m tipsy after half a glass). Another subset (including many Asian people) honest-to-goodness doesn’t metabolize alcohol well, thanks to a genetically encoded difference in an important enzyme, and turns hot, red, and otherwise uncomfortable in response to any alcohol. None of these are actually allergies.

So, do wine allergies actually exist? Yes.

Back in 2012, a group of German epidemiologists sent out a survey asking random adult residents of Mainz whether they had experienced symptoms of “wine intolerance.” 7.2% of people who responded to the survey attested to some form of wine intolerance. I wrote about some problems with the study on Palate Press: the possibility that respondents might have confused “intolerance” symptoms with a hangover, the likelihood that the survey overestimated people with problems because they’re the most likely to respond (and three-quarters of people sent the survey didn’t respond), the power of suggestion. Still, the study begs the question. How many people really are allergic to wine?

The same group has followed up with more research aimed at answering that question. Of the 68 people marked as “wine intolerant” by the original survey, they convinced 19 to sit down, along with ten non-intolerant controls (mostly women), for a battery of allergy testing. In addition to the familiar skin prick test – inject a bit of potential allergen X under your skin to see if you come up red and swollen – they also used several blood tests all looking for the release of inflammatory molecules in response to wine and grape products, including riesling, pinot gris, pinot noir, and dornfelder wine. All of these tests measure reactions to grape proteins. These are true allergies, proteins that set off an immune response, not reactions to alcohol, biogenic amines, sulfites, or allergies to processing agents such as egg whites or milk proteins.

Seven of the 26 people prick-tested developed swelling in response to at least one of the wine or grape samples, four to wine and three just to grapes. 13 developed antibodies in response to grapes, but only nine of them had reported symptoms; the other four were in the asymptomatic control group. Only one person was wine allergy-positive in all four different types of tests.

The conclusion? People can be allergic to specific kinds of grapes, wines, or both, just as people can be allergic to citrus fruit, tomatoes, or olives. It’s probably not very common. This study was small, far too small to say anything about how common wine allergies are in Germany let alone amongst other ethnic groups. Knowing how to respond to discrepancies among the tests, and between the tests and people’s reported symptoms, is an issue, too. Writing up their results for publication, the researchers ignored it. But again, no matter what exactly is going on there, we’re back at the first conclusion. Grapes, and wine, seem to be like other foods as far as allergies go. You might well have a wine allergy, or an allergy to red or white wine, or to a specific variety. You probably don’t.

Empirical evidence: organic/biodynamic vit = more textured wines

A six-year comparison of organic, biodynamic, and “low-input” and “high-input” viticulture (three years of conversion, three of maintenance) recently came to fruition in South Australia, courtesy of researchers at the University of Adelaide. The full report is freely available here (and three cheers for research freely shared). It’s 73 pages long, but the conclusions are fairly simple. The most worthwhile among them: in blind trials, experienced wine professionals rated the organic and biodynamic wines more interesting than the conventional versions.

  • Soil health (nitrogen, phosphorus, organic carbon, microbe mass) was most strongly improved by compost, not by any particular management system. All four systems were tested with and without compost.
  • Compost had the single most dramatic positive effect on soil health, no matter the underlying management system.
  • Management system had no consistent effect on vine growth, berry weight, or berry composition.
  • Low-input, organic, and biodynamic alternatives yielded at 91%, 79%, and 70%, respectively, of the high-input condition.
  • Organic and biodynamic wines were more “textural, rich, vibrant, and spicy” than their conventional counterparts. (pH, TA, and color held constant; high-input wines were a bit higher in alcohol.)

Improved soil health with organic/biodynamic management has been demonstrated numerous times over, and so have the benefits of compost. This study was unusual in making compost a separate variable, showing that both organics/biodynamics and compost, separately, were beneficial. The upside here is the attitude, across the study, that conventional growers can benefit from organic techniques even without undertaking a full-on organic conversion.

The downside is that the “organic” and “biodynamic” management used in the comparison are weak compared with what many committed non-conventional growers undertake. How can you practice biodynamics without compost? “Biodynamic” here seems to have meant nothing more than adding the core preparations 500 and 501, a far, far cry from anything Demeter would certify as honest biodynamics. Even the organic system is pretty bare bones: weed control with mowing and cultivation instead of herbicides; no insecticides or pesticides other than copper. (The low-input condition pulled back on the insecticides and some of the pesticides.)

Talking about those lower yields, the researchers make an important point. Very little research has been done on organic or biodynamic cultivation methods. We could develop better techniques within those systems and preserve environment and fruit quality while improving yields. Many organic/biodynamic growers have surely worked out such techniques on a local scale, which leaves a role for scientists to listen to what they’re doing, identify why it works and how/whether it can be generalized more broadly. Some environmentally conscious wine people are happy to pour their big pharma money (or whatever it might be) into projects they believe in with no thought for financial return, but most are trying to support their families as well as their values. Sharing successful organic/biodynamic techniques — say, for weed management, which was the biggest issue in this study — developing them scientifically, and stamping them with a scientific seal of approval so that they’re not dismissed as just those quacky organic people, will help conventional growers improve their weed management tactics, too. Likely, too, with economic benefits you can appreciate even if you honestly don’t care about trashing the environment for short-term gains.

The researchers should have made another point about those yields. Are the high-input yields a reasonable benchmark? Should we buy short-term gains with long-term environmental and social damage? If your business isn’t “sustainable” without using chemical warfare to eke every last grape out of the earth, then perhaps you need to reconsider your business practices in other areas. It comes back to the old resurrecting dinosaurs argument. Just because we have the technology to do something doesn’t mean we should. The wine might even be more interesting.

 

Brett + bacteria = worse, or better

Microbiology has gotten a lot wrong studying yeast and bacteria. We’ve assumed, until quite recently, that if a microbe doesn’t grow in a dish it’s not there. And that a microbe is either on/live/growing or off/dead. And that we can study microbes in isolation — “pure culture” — away from other species in little sterile dishes and expect them to behave normally. In all fairness, microbiologists have sometimes seen these as a problems, but have mostly just gone on this way, writing books about what we think we know.

DNA detection and sequencing technology is showing just how many bugs don’t grow in dishes — “high throughput” technology can document (theoretically) all of the species in a drop of [insert favorite liquid here]. That’s pretty routine these days. And we’re slowly beginning to study how mixtures of microbes — you know, the way they live in the wild — behave in the lab. Wine was a bit ahead of the curve here: microbial enologists have been studying the goings-on of spontaneous and mixed fermentations since the late 1980’s.*

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