Aspartame (E951)
Aspartame is an intense low-calorie sweetener, which is very low in calories and is 200 times sweeter than ordinary sugar. It is made from the combination of two amino acids, L-aspartic acid and L-phenylalanine, which are both naturally present in everyday foods such as meat, vegetables, fruit, grains and mother's milk.
When aspartame is consumed, it breaks down into aspartic acid, phenylalanine and a tiny amount of the organic compound methanol. Large quantities of methanol can be toxic, however the low amounts derived from aspartame and a wide range of other foods are not considered to pose a risk to health.
By way of comparison a 115g banana contains as much methanol as a 330ml can of a carbonated soft drink sweetened entirely sweetened with aspartame. Similarly a 220ml glass of milk contains 7 times as much aspartic acid and more than 3 times as much phenylalanine as a 330ml can of carbonated soft drink sweetened with aspartame. Because the amino acids used to produce aspartame occur naturally, the body treats it in the same way as it would if the source was meat, cheese, vegetables, fruit juice or milk.
Labelling
People who suffer from the rare genetic metabolic disorder phenylketonuria (PKU) have to monitor and control their intake of phenylalanine from all sources of food and drink as they cannot break it down naturally in the body. The contribution of phenylalanine from aspartame is insignificant compared with that from many other foods such as milk, cheese, eggs, meat, fish, fruit and vegetables.
However in order to assist PKU sufferers, all products containing aspartame are clearly labelled 'contains a source of phenylalanine.'
PKU sufferers are identified at birth using a simple test which takes place within the first few days. Medical guidance is given as to how to handle this disorder.
Studies are continually in progress, evaluating aspartame's effectiveness in areas such as weight control, the improvement of dental health and diabetic management.