Theory: "How do triggers work?" Current theories of migraine explain that the nervous system reacts to headache triggers with a release of chemicals that cause blood vessels in the brain to expand, increasing brain blood flow. As the blood vessels expand, other chemical signals send pain messages to the brain, resulting in headache. So, headache sufferers are often told they can reduce headache frequency by limiting their exposure to triggers.
Headache sufferers have identified a wide variety of headache triggers. Stress is the most common trigger (75%), with menstruation, odors, sleep irregularities, weather, fasting, and exertion as the next most commonly listed suspects. While migraine sufferers are most susceptible, people with tension-type headache can also be affected by stress and other triggers. Although patients are generally advised to limit exposure to triggers, few studies have evaluated a relationship between certain avoidable triggers and headache. Some triggers, like changing weather patterns, are unavoidable.
For headache sufferers, it's important to know whether avoidance of certain triggers is likely to reduce headache or not. Studies that have evaluated the avoidance of specific headache triggers are highlighted below.
Fact or Fiction: "Eliminate the stress in your life." Stress is part of living and clearly cannot be eliminated. Reducing stress levels is also very difficult, since managing families and careers, nurturing relationships, and even celebrating holidays offer a variety of stresses. Life's changes, both good and bad, increase stress levels.
While eliminating stress is not possible, training our bodies to respond to stress in less harmful ways is both possible and useful. When confronted with stress, the brain releases chemicals that send "red alert" messages to the body, which responds with clenched jaws, tensed muscles and other "all systems go" changes. These physical consequences of stress increase headache activity. Stress management basically teaches people to control the body's reactions to life's stress, reducing the negative effects that stress has on headache. Extensive, well-designed studies have concluded that stress management skills, relaxation training and biofeedback are all effective in reducing chronic headache for 50% to 70% of patients.
Fact or Fiction: "Once you go through menopause, your headaches will go away." Migraine onset is linked to beginning menstruation, and 60% of women notice worsening of headache around the time of their monthly periods. Cycling of estrogen levels is directly linked to increasing headache. Controlling estrogen levels has been shown to improve women's headaches in a variety of studies.
Because of these associations, women may be advised that their headaches
will go away when they become pregnant or go through menopause. For young women diagnosed with chronic headache, this advice is often more frustrating than comforting. Pregnancy does result in reduced headache for 48% of women with migraine and 28% with tension-type headache. So, although headaches do improve for a large minority of women, most women will cotinue to have headache during pregnancy.
Menopause also changes headache. Interestingly, there are varying responses to menopause related to both type of headache and type of menopause. Two-thirds of women with migraine will have improvement after natural menopause. Only one-third will improve after hysterectomy or surgical menopause, and two-thirds actually have worsened migraine. Tension-type headache is less likely to change after either natural or surgical menopause. Many believe that the aging process that accompanies natural menopause is what results in reduced headache. Speeding up that process by hysterectomy is generally not helpful in decreasing headache.
Fact or Fiction: "Quit smoking." Nicotine changes the amount of pain-signaling chemicals in the nervous sytem, like endorphins, serotonin, norephinephrine, and dopamine. The ability of nicotine to alter these chemicals explains why people describe feelings of decreased anxiety or stress with the use of nicotine products. Nicotine use also is associated with increased pain levels in people who suffer from chronic pain.
Headache activity is also incrased in smokers, with headache activity directly linked to the amount of nicotine consumed--the greater the nicotine exposure, the greater headache frequency and severity become. Although case reports describe improvement in migraine and tension-type headache when nicotine use is stopped, well-designed studies are not available. Stopping nicotine has been shown to be helpful in reducing cluster headache. In my own practice headaches have been dramatically reduced in a few patients who quit smoking. In most, improvement is moderate. Smoking cessation is important for one's overall health, with an added benefit of possibly reducing headache activity.
Fact or Fiction: "Don't eat that! You'll get a headache." Restrictive diets are frequently prescribed for headache sufferers. Thesediets generally limit exposure to foods rich in substances known to have effects on the blood vessels. Restricted foods include those containing tyramine (aged cheeses, alcohol, sour cream), phenylethylamine (chocolate), nitrates (hot dogs), and dopamine (broad beanpods). One study compared headaches experienced by a group of migraine sufferers while they tried three different diets. These diets were their normal diet, a diet high in foods believed to trigger headache, and a diet low in foods believed to trigger headache. Headache improved on both the diet low in trigger foods and the diet high in trigger foods compared to the patient's regular diet. Following a structured diet caused headaches to improve, regardless of the diet. Headache occurrence was unrelated to exposure to most foods. However, headache did seem to occur more frequently when patients had been fasting, drank alcohol, or ate chocolate. Restricting foods containing tyramine, nitrates, and dopamine was not helpful.
Studies evaluating single foods are few and offer mixed results. One study showed that taking excessive amounts of aspartame (Nutrasweet) for four weeks increased headache frequency in a group of migraine sufferers who had identified aspartame as one of their triggers. There was no change in headache severity. Study participants took 300 mg of aspartame four times a day -- the equivalent of 12 cans of diet soda or 32 packets of sweetener every day for a month. More moderate use was not tested; this study showed only a small increase in headache after regularly consuming very large doses of aspartame.
Chocolate is another commonly reported headache trigger food for 22% of chronic headache sufferers. In a study we conducted, over 60 women with chronic headaches followed a restrictive diet and then were tested with four chocolate-flavored bars. Two of these bars were chocolate and two were carob. (Carob does not contain trigger chemicals.) All samples were flavored with mint to prevent volunteers from identifying which bars were chocolate. Even women who believed chocolate triggered their headaches did not have headaches when they didn't know if they were eating chocolate or carob. Cheating on the diet and eating other restricted foods like peanut butter, colas, or pizza along with chocolate did not result in increased headache activity either.
Since foods rarely seem to trigger headache, why are there such strong myths about them as headache triggers? The mood and behavior changes that precede a migraine attack often include food cravings. A false association can then be made beween eating the food and getting a headache. The food doesn't actually trigger the headache, but the craving is a sign that the headache process has already begun. In addition, sweet craving typically occurs in response to stress, fasting, and menstruation. Again, the true trigger may be the stress, fasting or hormonal changes, with chocolate (or other craved foods) a reaction to the trigger rather than acting as a trigger itself.
If you believe foods may trigger your headache, expect to get a headache within 12 hours of eating the food item. Elimination of certain individual foods may be helpful for a minority of headache sufferers, but restricting a wide variety of foods on a long-term basis can be stressful and is rarely helpful.
Drawing Conclusions: "What should I do?" Trigger avoidance may be very disruptive to one's lifestyle, and the effectiveness of most trigger avoidance has not been shown in well-designed, controlled studies. Stress management skills are clearly helpful in managing chronic headache. While these skills don't eliminate stress from your life, they do change the negative ways our body may react to stress, including headache. Nicotine use increases headache activity. Quitting tobacco use is good for overall health and also may improve your headaches. Dietary restrictions are not helpful for most people with migraines. Diets that restrict broad categories of foods may be useful to test for specific headache trigger foods but should not be maintained long term because of the risk of nutritional deficiencies.