Artificial Sweeteners Are Safe For Most People
If you live in Europe, all the artificial sweeteners you consume are tested and regulated by the European Food Safety Authority (EFSA), which sets acceptable daily limits. These limits tell you the maximum amount considered safe to consume each day, over the course of a lifetime.
The occasional can of diet drink is therefore not a problem. Because the limits are so high, a 70kg man would have to drink at least 14 cans a day, every day, to incur any health risks from the artificial sweetener itself.
Some people should be careful
These recommendations exclude one small subset of people: namely those suffering from the rare genetic disorder Phenylketonuria (PKU). PKU sufferers cannot break down the compound phenylalanine, and therefore should not consume aspartame. However, this applies to less than 1 in every 10,000 people.
A more common reason to exercise caution might be irritable bowel syndrome (IBS). For some people with IBS, eating too much xylitol (a sweetener in chewing gum and mints) can lead to diarrhoea or bloating. On top of that, if you're allergic to sulfonamides, you should avoid saccharin, as it can cause breathing difficulties, rashes and diarrhoea.
On a more positive note, the myth that artificial sweeteners cause cancer has now been solidly debunked. According to Cancer Research UK: "Large studies looking at people have now provided strong evidence that artificial sweeteners are safe for humans."
The myth first arose in the 1970s when studies on lab rats linked saccharin with the development of bladder cancer. These findings were so concerning that, until the year 2000, all food containing saccharin in the US was required to carry a warning label. Further testing, however, revealed that these findings were only applicable to rats and mice and had no relevance to people.
Another sweetener, aspartame, came under scrutiny in the 1990s, when a paper suggested it might be linked with brain tumours. However, a later study, involving nearly 500,000 people, found no connection at all.