What Causes Headaches?

Despite years of research, the actual mechanism behind most headaches is still a bit of a mystery. Originally, they were thought to be caused by either the restriction of blood vessels or the tightening of facial and scalp muscles. Modern studies suggest that headaches may be triggered by a low level of the natural pain reliever called serotonin. When serotonin levels drop, inflamed neurotransmitters in the face and scalp send out pain messages we perceive as headaches. After serotonin levels return to normal, most pain tends to subside.

There are a number of internal and external triggers for headaches, ranging from food sensitivities to clinical depression. What may work as a remedy for one trigger may do more harm than good for another. If the current serotonin/neurotransmitter theory holds true, then many medications used to relax muscles or open blood vessels may not be as effective as once believed.

One of the most common causes of headaches is emotional stress or depression. Feelings of anger or anxiety can cause muscular tension in the face and scalp, leading to a full-blown tension headache. Insomnia and depression can also trigger head pain, which gives some credibility to the connection between serotonin levels and facial nerve irritation. Some researchers suggest that emotions themselves do not trigger headaches, but they leave a person more vulnerable to the neurotransmitter/serotonin conflict. Repressed emotions also tend to trigger more pain than expressed anger or anxiety.

Other common triggers are food and chemical sensitivities. Some may be familiar with the concept of a Chinese Restaurant headache. The root cause of head pain experienced after consuming Chinese food is a sensitivity to a flavor enhancer called monosodium glutamate (MSG). In other foods, MSG may appear on the ingredient list as hydrolyzed vegetable protein instead.

Other headaches may be triggered by foods containing tyramine, an amino acid known to affect the body's serotonin levels. Sufferers should avoid consuming high levels of chocolate, sour cream, yogurt, aged cheeses and organ meats. Another chemical to avoid when battling headaches is a preservative called nitrites. Many canned or processed meats contain significant levels of nitrites, which help to keep the meat fresher and provide a healthy pink color. The triggering mechanism of nitrites may be the same as monosodium glutamate, causing pain through an allergic reaction.

Some sufferers believe caffeine is both a trigger and a cure. On the positive side, many headache medications contain caffeine to speed the medicine through the digestive system and into the bloodstream. Once the medication reaches the source of the pain, the caffeine stimulates the circulatory system for even faster results. Unfortunately, caffeine can also cause headaches for sensitive people, especially at higher dosage levels. The sudden crash after ingesting caffeine can also lead to a "caffeine headache," a form of withdrawal only relieved by time or more caffeine.

One common trigger is the consumption of alcohol. Some red wines contain tyramine, which can trigger food sensitivity headaches. All forms of alcohol can cause dehydration, which is the main trigger behind the infamous hangover pain experienced the morning after a bout of drinking. Some researchers also believe that alcohol causes blood vessels to expand, which can trigger headaches as they later attempt to contract.

Other triggers include glare, poor lighting conditions, medication interactions, eyestrain and physical exertion. Sinus troubles are not responsible for a significant number of headaches, even though the sinus cavities themselves are very close to the neurotransmitters that may be the culprit. It can be very difficult to self-diagnose headaches, so a trip to a physician, allergist or eyes, nose and throat (ENT) specialist may prove helpful.