Substances such as chocolate and glutamate are triggers of migraine. These and some other “migrainous substances” contain little or no tyramine. This suggests that other dietary factors are involved in the precipitation of migraine. These food substances play a role in the utilization of copper, which is known to be involved in the metabolism of vasoneuroactive amines such as serotonin, tyramine and the catecholamines.
This paper suggests that it is the effects that these substances have on the copper pathway (i.e. its absorption and utilization) that is the primary consideration in the precipitation of migraine. Chocolate contains high levels of copper. Glutamate acts to bind and transport significant amounts of copper between blood and tissues. Citrate, found in “migrainous citrus fruits,” increases the intestinal absorption of copper; and both ascorbate and citrate may act to decrease oxidation of tyramine and serotonin, thereby raising the effective levels of these substances and perhaps triggering a migraine attack.
A migraine episode would be made more likely upon the ingestion of these substances by susceptible individuals with abnormal copper metabolism such as lowered levels or altered ceruloplasmin, transferrin or albumin (known to bind copper), or a change in copper transport.