Aspartame

Aspartame is a high-intensity sweetener used to provide sweetness in foods and beverages. Chemically, it is the methyl ester of a dipeptide formed from the amino acids aspartic acid and phenylalanine. Aspartame is about 200 times sweeter than sucrose, or table sugar, so only small amounts are needed to produce a sweet taste .^1,2

After ingestion, aspartame is broken down in the gastrointestinal tract rather than remaining intact. Its digestion yields phenylalanine, aspartic acid, and methanol, which are then metabolized by the body. Although aspartame provides energy, the very small quantities required for sweetening mean that it contributes little energy in typical food uses .^1,2

Aspartame belongs to the functional category of high-intensity sweeteners, but it is chemically different from sweeteners such as saccharin, sucralose, and steviol glycosides. It is also distinct from sugar alcohols, or polyols, which are generally used in much larger quantities. Aspartame is relatively unstable during prolonged heating, which can reduce its sweetness and limit some applications in cooked or baked foods .^1,2

Because aspartame is a source of phenylalanine, it has particular significance for people with phenylketonuria (PKU), an inherited disorder in which phenylalanine metabolism is impaired. Products containing aspartame may therefore be required to carry labeling that alerts people with PKU to the presence of phenylalanine .^1,2