Aside from the socially relaxing effect wine often has on a person, there is great debate on whether or not wine is “good for you” or not. Is wine healthy? Or is it dangerous? The headlines every other day seem to contradict themselves and cause confusion.
Is Wine “Healthy”?
If one had to put a single blanket statement on whether or not wine is “healthy”, then the answer would have to be ‘no’. Everyone has different genetics, health conditions, et cetera, and would thus be affected by wine in different ways.
Think about it using another culinary example: kiwi fruit. Kiwis are loaded with vitamin C and dietary fiber, and is known to be beneficial for cardiovascular health, digestive health, as well as immunity. Kiwi is good for you, right? Well, for some people, yes! But, for many others, eating kiwi triggers allergic reactions with symptoms ranging anywhere from tingling in the throat and mouth to death. For them, kiwis certainly are not a healthy option.
The analogy isn’t perfect when compared to wine, as the effects of alcohol aren’t equivalent to an allergic reaction from eating food, but the point is the same. Wine may be beneficial for some people when consumed in moderation, but it could be harmful or even deadly to others, particularly those with health issues related to alcohol consumption.
The Story of Resveratrol
Resveratrol, the most ‘famous’ of wine’s health-benefitting polyphenols, has antioxidant, anti-inflammatory, and even anti-bacterial properties that can improve many aspects of one’s health or prevent an array of diseases from occurring. There are many other polyphenols that also have similar characteristics, but for the sake of this relatively brief article, we’ll mostly focus on resveratrol.
The big problem with the resveratrol-is-good-for-you theory is that the amount of resveratrol required to have any therapeutic effect is significant. In fact, the only feasible way to actually benefit from the health-benefitting properties of resveratrol and other polyphenols found in wine is to take them in purified supplement form.
Let's do some calculations...
A 2016 study in the journal Advances in Nutrition did the calculations of the amounts required of many different foods and beverages in order to achieve a therapeutic dose of 1g per day of resveratrol. To absorb this much of the polyphenol, one would have to drink between 505 and 2,762 litres of red wine, 3,448 litres of rosé, or 2,564-17,544 litres of white every 24 hours. That’s between 673 and 3,683 75cl bottles of red, 4,597 bottles of rosé, or 3,419-23,392 bottles of white.
Assuming those calculations are even remotely accurate, that’s enough to kill any human being a very long time before they obtained any therapeutic benefit from the resveratrol.
But, for the sake of argument, let’s accept that, when consumed in certain amounts, wine can have a positive effect on one’s overall health and wellness. Between synergist effects of other compounds in the wine coupled with other lifestyle habits and practices, let’s just say that one wouldn’t have to poison oneself to death in order to tap into some of these supposed health benefits of wine.
And Now For Something Completely Different
Now, let’s take a step back and look at another major issue impacting wine worldwide: climate change. With regard to wine, climate change has been shown to be impacting many aspects of the industry; from increased temperatures to more frequent and more violent weather events (hail, frost, severe drought, wildfires, et cetera), to forced ‘relocation’ to areas of the world previously not known for wine production (more northern regions, higher altitudes, et cetera).
Even the chemical composition of wine grapes have been shown to be affected by climate change, potentially changing the way our favorite wines taste in the future.
Now, if climate change is creating all these environmental/chemical changes in wine grapes (and everything else for that matter), wouldn’t that mean that the potential health benefits of wine would change as well?
Temperature is one of the biggest influences on plant physiology. It prevent stilbenes from forming - resveratrol is one such stilbene.
No Clear Picture
There are many studies examining the impact of climate change on chemical composition of wine grapes. As expected, however, the results vary from one study to the next. Part of this variability is simply due to the fact that there are many changes occurring, and expected to occur, with climate change, with each change impacting wine grapes in different ways. Additionally, depending upon where the grapes are located, the environmental pressures exerted upon them as a result of climate change will differ compared to vineyards someplace else.
The most obvious change is seen with climate change in overall increased global temperature. Studies have shown that temperature is one of the biggest influences on plant physiology, with increasing temperatures impacting grape composition by increasing sugar levels and lowering organic acid concentrations, in addition to changes in polyphenols and aromatic compounds.
While there are differences between studies, in general it has been shown that increasing temperatures have negative impacts on anthocyanin concentrations, as well as stilbene synthesis and concentration. Specifically, studies have shown that higher temperatures lead to the inhibition of the stilbene biosynthetic pathway, which in plain English means that higher temperatures prevent stilbenes from forming. Inconveniently for those advocating its health benefits, resveratrol is one such stilbene.
Humidity May Help
To complicate things a little more, one simply has to add in some of the other effects of climate change, specifically humidity and changes in rainfall patterns. A recent study found that high relative humidity levels (~89%) and increased rainfall had a positive impact on trans-resveratrol levels (particularly in the spring), while on the other hand, increased spring and summer temperatures were associated with decreased trans-resveratrol concentrations.
These results make sense, as resveratrol is utilized by the plant to fight off mildew and other nasty infections/diseases associated with increased moisture, so if the humidity or rainfall levels are higher, one would expect an increase in mildew and therefore an increase in resveratrol to help fight off that mildew. On the other hand, increased spring and summer temperatures resulted in the opposite trend – a decrease in resveratrol levels, the reasoning for which is less clear.
Another study supports this result, with that study finding resveratrol levels in Colli Piacentini Gutturnio DOC wines tended to decrease when the weather conditions were hot and dry.
It wouldn’t be science without contradictory research findings...
Of course, it wouldn’t be science without contradictory research findings. Another study found that while anthocyanin concentrations in several grape varieties were lower with increased temperature exposure, no effect was observed for resveratrol levels under the same conditions. This same study (like many others) found variety/cultivar differences, meaning climate change may – unsurprisingly - affect individual grape varieties differently.
So, what does this all mean? As the climate continues to change, and wine grapes are impacted in a myriad of ways, including alterations in chemical composition, will we see a change in the supposed ‘health benefits’ of wine?
Well, unfortunately it is impossible to say with certainty one way or another. One can theorize, however, that there will be changes to the health-benefitting polyphenol content of wine grapes, but these changes will vary from variety to variety, and region to region. Those areas that will see increased humidity and rainfall, may see increases in certain polyphenols such as resveratrol. On the other hand, with increased humidity and rainfall the grapes will be presented with a whole new set of challenges that may negate any possible changes in chemical composition.
For those areas suffering from increased temperatures and dry/drought conditions, without irrigation we might see resveratrol levels decreasing.
Of course, there is much more to this story than one compound and climate change’s effect on that compound. With climate change, we will likely see very complex changes to wine grape composition and subsequent chemical composition of the resulting wine. The exact effects are still unknown, and will continue to be only theories until more data is collected and analyzed.
But, one thing is certain: wine will not get healthier. It also likely won’t become any ‘less healthy’. Yes, the chemical composition will change, but due to the fact that one can’t drink the amount of wine needed to achieve therapeutic doses of these compounds before one poisons oneself to death anyway, any changes to the chemical composition of the grapes and resulting wine will have little to no effect on one’s overall well-being.
So, let’s stop debating the supposed health benefits of wine and just enjoy what we have while we still have it!
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De Rosas, I., Deis, L., Baldo, Y., Cavagnaro, J.B., and Cavagnaro, P.F. 2022. High Temperature Alters Anthocyanin Concentration and Composition in Grape Berries of Malbec, Merlot, and Pinot Noir in a Cultivar-Dependent Manner. Plants 11: 926.
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