A 33-year-old woman has been experiencing recurrent episodes of nausea, headaches, and dizziness for the past 8 months. She has come to the emergency department because she is concerned about her current episode, which is slightly different from her previous ones.
Her symptoms began in the early morning, waking her from sleep at around 5 AM. She had head pain, dizziness, and nausea-similar to the previous episodes-yet she has noticed flashing lights in front of her eyes. She also complains of tingling in both arms and hands, which had occurred with a few of her earlier bouts. She has been taking over-the-counter ibuprofen and acetaminophen all day long without improvement. She went to work as usual and has been trying to sleep since returning home from her job. However, she has been unable to sleep due to the pain.
She has been previously healthy. She has been taking oral contraceptives for birth control for the past 7 years. She has not recently had any changes to her oral contraceptive prescription. She has a normal menstrual cycle and has experienced monthly menstrual migraines for the past 5 years. They always improve with one or two doses of sumatriptan.
The recurrent headaches began about 8 months ago. They have been occurring about once a week and lasting between 24 to 48 hours. She has taken sumatriptan for her headaches, and, like her menstrual migraines, they improve with one or two doses.
She has a family history of inflammatory bowel disease, and when she began to experience intermittent abdominal discomfort a few years ago, she decided to become a vegetarian. She explains that she has been getting enough calories and protein intake since the switch in diet about a year ago.
The patient was afebrile, well-nourished, and healthy appearing. She had both a severe headache and nausea. She complained of dizziness, but the dizziness does not interfere with her ability to walk. She felt the urge to vomit several times during the evaluation, but instead of vomiting large amounts, she gags.
The skin appeared normal, with no bruises or rashes. Throat examination was normal, as was thyroid examination. The chest examination was normal, with clear breath sounds. Her cardiac examination reveals a regular heart rate and rhythm. Pulse were palpable and normal in bilateral upper and lower extremities. Her carotid arteries were normal with no bruits. Abdominal exam was normal, with no pain, tenderness or masses.
The patient was alert and oriented x3. Her speech was normal. Extra ocular movements were intact with no nystagmus, and her vision was normal. Pupils were equal, round ,and reactive to light. She did not have ptosis or facial asymmetry. She had photophobia. Facial sensation and movements were normal bilaterally.
She had normal strength in the bilateral upper lower extremities. Reflexes were slightly brisk in bilateral upper and lower extremities, with no asymmetry. Sensation was normal in bilateral upper and lower extremities to touch, pinprick, vibration, and position sense. She had no ataxia or dysmetria in bilateral upper and lower extremities. Gait was normal and she could perform a Romberg test and heel to toe walking without any difficulty.
Lab tests: CBC with differential, electrolyte levels, a B12 level, and thyroid tests, all of which were normal.
Imaging: Brain MRI and MRA were completely normal.
Nutrition: On further questioning, she insisted that she was not deficient in vitamins, minerals, or protein and that she eats tofu, edamame, or soy-based imitation meat products once per week when her office colleagues order lunch from a nearby vegan restaurant. Weekly migraines typically occur in the evening following these lunches, or wake her from sleep around 3 the next morning. She reported that she had never tried these products prior to becoming a vegetarian.
Diagnosis: Soy-induced migraine headaches and allergies
This patient has a classic description of migraine headaches, but the frequency of her headaches has suddenly changed, which is concerning. Given that she recently became a vegetarian, it would make sense to test for nutritional deficiencies.
Soy products can cause headaches or allergies in susceptible individuals, particularly among women who are prone to hormonal headaches.1 Soy metabolism is associated with estrogen, which has been proposed as a possible explanation for why it is an uncommon headache trigger.
Soy can also cause allergies, and recent modifications in soybean production have been focused on reducing allergens. However, some individuals may be allergic to soybeans, even after the modifications have reduced allergic responses in the overall population.2
Given this patient’s history, the best treatment plan was to focus on eliminating her probable headache trigger, and observing her clinical response. If she continues to have headaches after the probable trigger is removed, then other possible factors for increased headaches could be considered, such as health risk factors or emotional stress or anxiety. Often, there is no identified cause for an increase in migraine frequency. Given her weekly headache pattern, she may benefit from prophylactic therapy.
Take home points
• Nutritional deficits should be evaluated in patients who have had dietary changes.
• In addition to considering nutritional deficits, patients who have had dietary changes may also have new exposure to food or supplements that could cause allergic reactions or other symptoms.
• Women who have menstrual or hormonally induced migraine headaches are especially prone to soy-induced headaches.
• Because soy metabolism has been associated with estrogen, it was previously recommended that any women who have a risk of or a history of breast cancer avoid soy products. However, more recent research disproves a link between soy and breast cancer.3