I’ve been emailing with a biochemist who states that people that react to Aspartame have a folate (folic acid) deficienc ^[1]y. He says that they aren’t reacting to the Aspartame but to methanol which is a by product of its breakdown. He states that small amounts of methanol can also be found in pectin, fruit juices, and alcoholic drinks.  Folate is needed to get rid of the methanol, so he states that anyone who reacts to these things should be checked for folate.