Food additives can produce a range of effects, from depression, insomnia, nervousness, and hyperactivity to dizziness, blurred vision, and migraines. Research has established that aspartame (an artificial sweetener), aspartic acid (an amino acid in aspartame), glutamic acid (found in flavor enhancers and salt substitutes), and the artificial flavoring MSG (monosodium glutamate) are neurotoxins.105 Aspartame and MSG are particularly implicated in depression.