Aspartame

Aspartame (APM) is an artificial non-saccharide sweetener used as a sugar substitute in some foods and beverages. It is a methyl ester of the aspartic acid/phenylalanine dipeptide. Aspartame was first made in 1965 and approved for use in food products by the U.S. Food and Drug Administration (FDA) in 1981. Aspartame is one of the most rigorously tested food ingredients. Reviews by over 100 governmental regulatory bodies have found the ingredient safe for consumption at current levels. However, as of 2017, systematic reviews and meta-analyses of different types of evidence lead to different conclusions about its long-term health effects. The safety of aspartame has also been the subject of several political and medical controversies, United States congressional hearings, and Internet hoaxes. Aspartame is around 180-200 times sweeter than sucrose (table sugar). Due to this property, even though aspartame produces four kilocalories of energy per gram (17 kJ/g) when metabolized, the quantity of aspartame needed to produce a sweet taste is so small that its caloric contribution is negligible. The taste of aspartame and other artificial sweeteners differs from that of table sugar in the times of onset and how long the sweetness lasts, though aspartame comes closest to sugar's taste profile among approved artificial sweeteners. The sweetness of aspartame lasts longer than that of sucrose, so it is often blended with other artificial sweeteners such as acesulfame potassium to produce an overall taste more like that of sugar. Like many other peptides, aspartame may hydrolyze (break down) into its constituent amino acids under conditions of elevated temperature or high pH. This makes aspartame undesirable as a baking sweetener, and prone to degradation in products hosting a high pH, as required for a long shelf life. The stability of aspartame under heating can be improved to some extent by encasing it in fats or in maltodextrin. The stability when dissolved in water depends markedly on pH. At room temperature, it is most stable at pH 4.3, where its half-life is nearly 300 days. At pH 7, however, its half-life is only a few days. Most soft-drinks have a pH between 3 and 5, where aspartame is reasonably stable. In products that may require a longer shelf life, such as syrups for fountain beverages, aspartame is sometimes blended with a more stable sweetener, such as saccharin. Descriptive analyses of solutions containing aspartame report a sweet aftertaste as well as bitter and off-flavor aftertastes. In products such as powdered beverages, the amine in aspartame can undergo a Maillard reaction with the aldehyde groups present in certain aroma compounds. The ensuing loss of both flavor and sweetness can be prevented by protecting the aldehyde as an acetal. The safety of aspartame has been studied since its discovery. Aspartame is one of the most rigorously tested food ingredients. As of 2017, systematic reviews and meta-analyses of different types of evidence lead to different conclusions. Observational cohort studies show no or some correlation with negative health outcomes such as diabetes, heart disease and increased body mass index (BMI), though without providing conclusions about cause and effect for whether people could be consuming sweeteners because they have poor health, or whether they have poor health because they consume sweeteners. Randomized controlled trials instead show no or some causal positive health outcomes for the same health metrics. Reviews by governmental regulatory bodies have found aspartame safe for consumption at current levels. Aspartame has been deemed safe for human consumption by over 100 regulatory agencies in their respective countries, including the UK Food Standards Agency, the European Food Safety Authority (EFSA) and Health Canada. Observational cohort studies show a correlation with no or some increase in body weight or BMI, while randomized controlled trials instead show no or some causal decrease in body weight or BMI.