When a headache comes on, many people blame stress or lack of sleep. However, evidence suggests that hangovers can be brought on not just by alcohol, but by certain foods. The link is controversial, especially since the few studies on the matter have been inconclusive. However, for people who suffer from migraines and tension-type headaches, many report fewer symptoms if they eliminate certain "trigger" foods from their diet.

Ellen Loughrin, 51 years old, said to the Wall Street Journal that she started seeing a doctor after suffering from migraines, fatigue, and vertigo. Her visits prompted her to stop eating pizza, onions, oranges, yogurt and peanut butter, one of her favorite foods. A year later, her symptoms were drastically reduced.

Researchers believe that tyramine, a commonly occurring chemical in food, may be a possible culprit. However, the studies have found it difficult to pinpoint a specific biological link. Headaches can be triggered from a number of different factors, like weather or sleep, in combination with a food item. What triggers headaches in one person, like cheese, may not do so in another. What's more, because symptoms can appear as late as 48 hours after the ingestion of a certain food, it can make it even more difficult to finger a particular food.

However, researchers believe that they may have begun to shade in some clues. Tyramine can build up in foods that have been aged, fermented or stored for a long period of time. Other common culprits are foods with nitrates, like processed meats; citrus; yeast; soy products; monosodium glutamate, or MSG; and caffeine and alcohol, even in small amounts.

While the link may cause some to be skeptical, as many as 50 percent of migraine sufferers say that their pain has caused them to change their diets. Skeptics should also note that, while alcohol is commonly regarded as the main cause of hangovers, evidence has not pinpointed a link between the two.