What components of wine might cause headaches and upset stomach?

Q: My wife has recently been experiencing headaches and upset stomachs after just a glass or two of red or white wine. Are there any wine ingredients that might cause this that we could try to avoid?

A: The first step in identifying the cause of your wife's symptoms is to consult a doctor—your wife shouldn't play red-wine roulette with her health!

That said, there are many reasons that a person might have a bad reaction to a glass of wine, starting with the fact that wine contains alcohol. You don't mention whether your wife can enjoy other adult beverages without experiencing these reactions, but if she can't, she may suffer from alcohol intolerance, an inherited genetic trait associated with flushing. Caused an enzyme deficiency, it prevents the body from properly processing a byproduct of alcohol metabolization. Also, if your wife has recently started any new medications or supplements, she should check if they interact badly with alcohol.

Another possibility is that your wife has developed an allergic reaction. In the past, sulfites (additives that help keep wine, and many foods, from spoiling) were thought to be the main culprits behind headaches and allergic reactions from wine, but allergists report that less than 1 percent of the population is actually allergic to sulfites.

Histamines and tannins have also been blamed for allergic reactions, but those are also disputed, and other theories are being explored.

Proteins in milk, eggs and fish are sometimes used as fining agents in wine; while little to none of the protein may be left in the finished wine, some countries require wineries to label wines made with these potential allergens.

Other possible allergens could be oligosaccharides, carbohydrates found in the above-mentioned glycoproteins. According to a study published in 2012 in the Journal of Agricultural and Food Chemistry, more than 45 oligosaccharides were identified in wine. Certain oligosaccharides are known allergens, but the jury is still out on whether people with allergic reactions to wine are reacting specifically to these compounds.

The bottom line is that the more scientists have studied wine, the more potential allergens have been identified. Searching for the cause of your wife's symptoms may be tantamount to looking for a needle in a haystack, unless you enlist the help of a physician and possibly an allergist.

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