Aspartame-sweetened soft drinks have been linked to seizures, according to the Epilepsy Foundation. The chemical has also been known to induce convulsions. This synthetic chemical can evade the blood-brain barrier, allowing the chemicals to directly alter the brain’s neurological function. It is believed that aspartame, which contains phenylalanine, can raise the levels of phenylalanine in the brain. It then reduces the production and flow of the neurotransmitters that protect against seizures. The seizure threshold is raised by drinking alcohol, according to studies, and declines after stopping. As a result, during withdrawal from alcohol, usually in the first two days, seizures may occur.