Platelet phenolsulphotransferase deficiency in dietary migraine.

Patients with dietary migraine were found to have significantly lower levels of platelet phenolsulphotransferase activity than either migrainous patients without a history of dietary provocation or normal controls. Of the two known human variants of this enzyme, the phenol-inactivating P form, for which no endogenous substrate has so far been identified, was more severely involved than the M enzyme, which inactivates monoamines (including tyramine). Such commonly implicated dietary triggering agents as chocolate and cheese may contain as-yet-unidentified phenolic substrates of phenolsulphotransferase P; if the platelet enzyme deficiency were mirrored by low gut activity, abnormally large amounts of potentially toxic substances might gain access to the circulation in consequence.