Q: As wine ages, do its health benefits change?—Lynn, Mexico City
A: Wine undergoes a variety of chemical changes as it ages, some of which still aren’t clearly understood. In red wine, tannins, which are themselves a type of polyphenol, join together (or polymerize) to form larger, chain-like molecules. Some of these fall out of the wine as sediment, which is why it’s advisable to decant many (but not all) older wines. Other molecules undergo their own reactions, and those that remain in solution may contribute to the mouthfeel, flavor and aroma that make older wines, both red and white, so appealing to many drinkers. In particular, we have these complex chemical reactions to thank for the tertiary aromas and flavors such as truffle, leather, forest floor and beyond that fans of mature wines love.
Dr. Véronique Cheynier, polyphenol research director at France’s National Research Institute for Agriculture, Food and Environment, told Wine Spectator that it is “quite clear that wine polyphenols evolve during aging.” They do so by both polymerizing to produce larger molecules and breaking apart to produce smaller molecules. These smaller molecules can react further, in a highly complex process involving “random cascade reactions” that continuously compete with one another as wine ages.
It’s unclear what all of this means for wine’s potential health benefits. Dr. Roger Corder, emeritus professor of experimental therapeutics at Queen Mary University of London and author of The Red Wine Diet, has suggested that the main cardioprotective molecules in wine are procyanidins. Procyanidins belong to a larger class of flavonoids called proanthocyanidins, also called condensed tannins, which, according to Dr. Cheynier, “are the major phenolic compounds in red wines.” Dr. Corder found that “grape pip procyanidins had potent effects on blood vessel function that could account for the ability of red wine to prevent heart disease.” Moreover, young, red wines with pronounced tannins contain the highest concentration of these procyanidins—and therefore seem most likely to confer a health benefit. According to Dr. Corder, “Aging of red wines to the point where these tannins precipitate and form a deposit will certainly result in a reduction of the protective properties of procyanidins.”
Though researchers disagree about the potential health benefits of resveratrol, which Dr. Cheynier calls “a minor compound in wine,” it remains one of the most recognized polyphenols among wine drinkers, and many studies have linked it to potential health benefits. However, a 2020 study of Australian red wines found a dramatic decrease in trans-resveratrol concentration over time, which “may reduce the anticipated health benefits of the wine.”
What about white wines, some of which can age gracefully for many years, or even decades? Though the alcohol content of white wine may confer modest health benefits, and some research has linked the polyphenol protocatechuic acid to improved bone health in older drinkers, Dr. Corder’s view is that white wines, whether young or old, “generally have undetectable levels of grape pip procyanidins” and are unlikely to confer significant health benefits.
The best advice, especially in the case of older wines, may be to drink wine because you like it—not because you’re expecting a specific health benefit—and to drink in moderation. As always, ask your doctor about incorporating wine, young or old, into a healthy lifestyle.—Kenny Martin