Many people have been worried that aspartame, the dominant sweetener in Diet Coke and Diet Pepsi, may cause everything from brain tumors to cancers, but many of these fears are largely unfounded.
If you suffer from PKU, a genetic disorder, or are on certain medicines such as medications that contain levodopa, monoamine oxidase inhibitors, or neuroleptics, aspartame may be unsafe for you to consume.
Aspartame has been deemed safe in Europe, but labeling of the sweetener is mandatory there.
Aspartame is about 200 times sweeter than sugar.
Diet Coke and Diet Pepsi are options that are currently considered safe for people who have diabetes.
Several supermarket chains in the UK, including Sainsbury's and M&S, have stated that they will no longer use aspartame in the products that bear the store name in response to customer concerns.
In one study, rats gained the same amount of weight whether they were ingesting saccharin, aspartame, or sucrose (sugar-water).
Other studies have shown that weight gain was promoted by the use of aspartame or saccharin as compared with sucrose, although it was suspected that this might have to do with less energy being expended and that the diet drinks may have encouraged fluid retention.
Both the European Food Safety Authority and the U.S. National Institute of health have determined that aspartame has been studied at length and is safe for human consumption.
However, other concerns have been raised about the general health effects of aspartame. Dr. Morando Soffritti, Director of the Ramazzini Institute in Bologna, Italy, has suggested that the initial 1970s studies on aspartame showing that it was safe weren't very good studies.