(Orlandosentinel) - That great glass of cabernet sauvignon can sometimes come with a price — a headache.

Setting aside those who suffer routinely from migraines or someone who tied one too many on the night before, even people not normally prone to headaches can sometimes feel the effect after a simple glass or two of red wine.

Sulfites often get the blame for causing the affliction, but experts said it's highly unlikely sulfites are the culprit and that two other substances are probably at fault.

Andrew Waterhouse, wine chemist in the Department of Viticulture and Enology at the University of California at Davis, said people may think sulfites are the problem because of the "contains sulfites" phrase seen on wine labels since the 1980s.

"They look at the bottle ... and they think, 'Oh my goodness, if it contains sulfites, that must be dangerous,'" he said.

Most winemakers add a small amount of sulfites to keep wine from oxidizing, and sulfites occur naturally during fermentation.

Sulfites are used to keep foods from browning, for instance, at salad bars or in dried fruit, and a very small percentage of people have a sulfite allergy, hence the Food and Drug Administration's decision to require the label, Waterhouse said.

Dr. Frederick G. Freitag, a headache specialist and associate professor at the Medical College of Wisconsin, said headache is not a common symptom of allergies.

"You never hear about 'the salad-bar headache,'" said Freitag, who has studied, for nearly 25 years, why wine might cause head pain.

Freitag said red wine headaches are likely linked to tyramine and tannins.

Tyramine is a naturally occurring amino acid, often produced by fermentation. It can affect blood pressure and has been known to trigger migraine headaches in people who can't break down the substance, Freitag said.

Kristin Kirkpatrick, a registered dietitian and manager of nutrition services at theCleveland Clinic Wellness Institute, said aged foods such as cheese have high tyramine levels. Consuming wine and cheese together can compound the headache risk, she said.

Freitag and Waterhouse said there's growing evidence that tannins are why some people get headaches after light red-wine consumption. Freitag said tannin is a catchall term for the naturally occurring chemical substances found in grapes and wine, and most of them are found in grape skin and seeds. In white wine production, most of the skin and seeds are removed, but in red wine those are kept as part of the fermentation process.

Phenolic compounds, which are related to tannins, can get absorbed into the bloodstream and metabolized by the body to open the blood vessels, called vasorelaxation, "a key step in getting a headache," Waterhouse said.

Flavonoids are also related to tannins — with the best known one being resveratrol, which supports heart health, Freitag said.

In combination with tannins, stress may also affect whether headaches occur, which is why people may not get headaches drinking wine on their European vacation, but do after a hard day of work.

What to do?

Aside from not drinking red wine, Dr. Seymour Diamond, executive chairman of the National Headache Foundation and the director emeritus of the Diamond Headache Clinic, offered a few prevention tips.

Drinking two strong cups of coffee before imbibing can help, Diamond said, because caffeine constricts the blood vessels and can inhibit vasorelaxation. A little bit of honey in coffee can help, as the fructose in honey can metabolize the alcohol faster.