Aspartic acid is another normal neurotransmitter within the brain. As we have already seen, anything taken to excess can be toxic, and that is also true for aspartic acid. Methanol, or methyl alcohol, is naturally found in fruits and vegetables. It occurs both as the free alcohol and bound in the form of compounds called methyl esters. Pectin is an example of a food component which contains methyl ester groups and which is present in all fruits and vegetables.
Methanol is released when such esters are digested.
Europeans typically consume 2 to 5g of native pectin a day, which provides up to 0.7g methanol. These quantities of methanol, plus those from other sources, are routinely handled by the body with no ill effect. Aspartame is also a methyl ester. However, because aspartame is a potent sweetener, only tiny amounts are used and correspondingly minute quantities of methanol are produced. In experiments, people have swallowed large amounts of aspartame with no detectable effect on blood formate concentration.