Q: Is natural wine made with low or no sulfur good for my gut microbiome?—Rafa, Milan
A: Our last Health Q&A looked at the digestive health effects of wines made with wild (or indigenous) yeasts. While those wines are unlikely to carry any special benefit to gut health, different types of wine may impact the digestive system in different ways. What about so-called ‘natural’ wines made with low amounts of sulfur, or none at all?
What Is Sulfur Dioxide, and Why Do Winemakers Use It?
Winemakers commonly add small amounts of sulfur dioxide at bottling as a preservative and antioxidant. Some wines are made with low levels of added sulfites, or none at all, including many wines described as natural. Those wines often involve spontaneous fermentation with wild yeasts and are unfined and unfiltered, which sometimes gives them a cloudy appearance. Many representative orange wines are also made using skin contact.
While these wines can be delicious, they’re also prone to various kinds of microbial spoilage. Bottles that get shipped long distances or stay on a shelf for a long time are particularly prone to going off, since they lack the protective effect of sulfites.
No wine is completely free of sulfites, which are a natural by-product of alcoholic fermentation. Moreover, many foods (including dried fruits, canned goods and more) contain much higher amounts of sulfites than wine. And while some people do have a true sulfite allergy, it’s extremely rare. Symptoms typically involve hives, wheezing, sneezing and a runny nose—not headaches or an upset stomach.
Natural Wine and Gut Health
Dr. David Mills, a distinguished professor of food science and technology at UC Davis, told Wine Spectator that low-sulfur wines are highly unlikely to have any special benefits to gut health compared to wines that contain standard amounts. “There’s no evidence of any sort that I’m aware of that [the microbes in wine] have what you might call a probiotic effect.” Even in the case of so-called natural wines, Mills says, there’s “very little” in the way of microbes in wine.
While it seems logical that natural wines would contain more potentially beneficial microbes than traditionally made wines, Mills says that no matter the type of yeast used or amount of sulfites added or not added, wine simply isn’t a very good source of probiotics. Some styles of natural wine may taste and look a lot like kombucha, but they aren’t going to pack the same microbial punch.
The vast majority of the microbes in a wine will be inactive or dead by the time it reaches your glass. If sulfur dioxide doesn’t kill them, alcohol will. And even if you found a wine with a relatively high concentration of living microbes, you’d have to consume far more than a safe amount—many, many bottles in one sitting—to see any kind of benefit to gut health. As Mills puts it, “Nobody’s drinking five bottles to get the right amount of bug.”
Looking Beyond Wine
What are wine lovers hoping to improve their gut microbiome to do? “We all need to eat about 10 times as many vegetables as we’ve been eating,” says Mills, noting their well-documented positive impacts on digestive health. The fiber, polyphenols and more in vegetables all contribute to a healthy gut.
Mills also recommends that people incorporate other fermented foods besides wine that do contain significant levels of probiotics. Those include yogurt, kimchi, sauerkraut and more. Mills emphasizes that since these fermented solid foods contain so much more biomass than liquids like wine, they stand to benefit gut health much more. Wine, he says, “is just not going to deliver” anything like the amount of microbes these foods contain.
As always, talk to your healthcare provider about incorporating wine into a healthy lifestyle.—Kenny Martin
