Most people suffer from headaches. In fact, it has been estimated that almost half of the adult population has had a headache at least once within the last year, according to the World Health Organization. Typically, they’re a result of stress, certain foods or alcohol, changes in sleep or skipped meals — but there are other triggers that you probably didn't know. The following facts about some of the more unusual headache causes has been compiled from Prevention and Everyday Health.

Smoked, pickled, dried, or aged food

Consuming things like aged cheeses, salami, wine, and smoked salmon can give you a headache because they contain sulfites, which may dilate your blood vessels.

Fragrances

The most common smells that trigger headaches are gasoline, tobacco, and perfume, Alexander Mauskop, MD, director of the New York Headache Center and author, told Prevention.

Computer Screen

The variation in light and the brightness from your phone or computer screen activates your retina and the nerves behind your eye, which can cause head pain.

Dehydration

Dehydration headaches are a result of losing a substantial part of the water and electrolytes necessary to perform normal functions. Some experts believe that they occur as a result of narrowing blood vessels while the body tries to maintain enough fluid.

Caffeine withdrawal

“Caffeine can have physiological effects on the vascular system and can constrict vessels or relax them at different times,” Mia Minen, MD, neurologist and director of headache services at NYU Langone, told Everyday Health.

Anxiety from close relationships

Do social situations and relationships make you nervous? Anxiety results in taking shorter breaths, Nicole Glassman — owner of Mindful Health, a holistic health center in New York — told Prevention. Head pain is caused by a result of less oxygen in the body and blood vessel constriction.

Too-tight hairstyle

It’s no surprise that hairstyles that pull on your scalp cause tension in the cranium. In fact, more than half of all women experience a tension headache from a too-tight hairstyle, according to a study by researchers at The City of London Migraine Clinic.

Brain freeze

Researchers don’t know what causes brain freeze, or “ice cream headache,” but scientists at the Johns Hopkins Headache Center found that it is thought to be “a combination of direct stimulation of temperature-sensitive nerves plus the cold’s effects on blood vessels running along the roof of the mouth.”

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