Artificial sweeteners are popular because it is claimed they limit calorie intake and thus lead to weight loss. This is based mainly on supposition however, as the nutritional literature does not support this contention. In fact studies on artificial sweeteners show they may actually increase food intake and cause body weight gain. Disregarding any possible effects on weight gain, the ubiquitous nature of artificial sweeteners necessitates a basic understanding of their effects.
Aspartame is perhaps the best known sweetener. It is composed of phenylalanine and aspartic acid, two amino acids, joined to a molecule of methanol. Aspartame is roughly 200 times sweeter than sugar and is now added to products in addition to sugar. In the body aspartame is broken down to formaldehyde, and it is for this reason that aspartame is widely believed to be carcinogenic. In addition, aspartame may alter brain chemistry because of the amino acids it contains.
Stevia is a natural sweetener extracted from the Stevia rebaudiana plant. Stevia is roughly 300 times sweeter than sugar. Stevia is widely used as a sweetener in Japan, but is only available as a dietary supplements in many other countries. A number of glycosides are responsible for the sweet taste is stevia and these have now been isolated and given a generally recognised as safe label by the United States Food and Drug Administration.
Xylitol, Mannitol and Sorbitol
These compounds are described as polyols or polyalcohols. Polyols are roughly 60 time sweeter than sugar. Because they are poorly absorbed they can be added to foods to increase sweetness without changing the energy content of the food too much. However, in larger doses they are known laxatives as they changes the osmotic potential in the gut due to their low absorption. In this regard they can be effective at low doses but at high intakes may be problematic.
Like aspartame, concerns over saccharine centre on the possibility that it is a carcinogen. No convincing human studies have demonstrated a carcinogenic effect, and this is not unusual due to the length of time cancer takes to form. However animals studies involving rats do suggest that saccharine might be carcinogenic. Like aspartame, saccharine is also around 300 times as sweet as sugar and is widely used in many different foods.
Acesulfame K, also called acesulfame potassium (K being the elemental symbol for potassium), is roughly 200 times sweeter than sugar, and is not absorbed by the body. As with aspartame and saccharine, The use of acesulfame K in the food industry as an artificial sweetener is widespread. Acesulfame K can produce a bitter aftertaste when ingested in high concentrations and for this reason is often blended with other sweeteners or used with masking agents such as sodium ferulate.
Sucralose is chemically related to sucrose, but it has additional chlorine atoms attached to its structure. Sucralose is roughly 600 times sweeter than sugar and is not broken down by the body and so does not provide any energy. Sucralose is widely used in baked good because it is heat stable and for this reason has been produced in a granulated form to resemble sugar. Sucralose provides no energy to the body, but is often packaged with dextrose or maltodextrin that do.
Tagatose is a naturally occurring sugar found in milk that is slightly less sweet than sugar. Tagatose is absorbed poorly and while it does supply some calories to the body, it may actually beneficially modulate the glycaemic response to some other sugars through competitive absorption in the intestines. While tagatose can inhibit the absorption of other sugars it has minimal effects on plasma glucose or insulin release itself.