According to the Roman philosopher Pliny the Elder, “The best kind of wine is that which is pleasant to him that drinks it” but modern science expects more specifics. (The point of course is that if you have a wine that you enjoy you are more likely to drink regularly and therefore reap the benefits.) But there are several difficulties in singling out certain wines for their healthful properties. Which compounds to measure? Are we talking about heart health or the whole gamut? Is it the varietal of the grape or the viticultural method that is most important? For all of these reasons there are different answers.
Let’s begin with the well-known anti-oxidant capacity of wine. Anti-oxidants of course play a role in reducing the risk of a range of diseases and wine polyphenols are among the most potent ones. One would therefore think that there would be plenty of published resource material but in fact there is surprisingly little. One study from France evaluated comparative antioxidant capacity and found the highest readings for grenache and pinot noir based wines, followed by syrah, cabernet sauvignon, and merlot. Interestingly, they also found significant year to year variation, indicating the importance of growing conditions. These factors in concert with region-specific viticultural techniques probably contribute as much or more to polyphenol content as varietal. Given that grapes express these compounds in response to stress it makes sense.
But looking specifically at the heart health question, it appears likely that the primary benefit comes from compounds called oligomeric proanthocyanidins (let’s agree to call them OPC’s) which are associated primarily with the seeds of the tannat grape. Malbecs from Argentina are reported to have respectable amounts of OPC's, as do wines from Spain and southern Italy. These compounds may impart a more bitter flavor, and so often the wines with high levels are more “rustic.” Australian reds, big and lovely though they are, often lack in this category.
One thing is sure, the health benefits of wine are not reducible to a list of chemicals anyway. It is all of them working together, with alcohol, with food, as part of a healthy lifestyle. Pliny had it right all along.