OK let me be clear, we are right as consumers to question, scrutinising a product is key to keeping the manufacturers and industry as a whole honest. However, sweeteners have been on the receiving end of some serious accusations that, on the whole, have been unjustified. Most famous of these is Aspartame, however the research has only seen contraindications in children which include headaches and hyperactivity, and although this is concerning, the same has not been seen in adults. With this in mind though, Aspartame has also been removed from many products as a result.
The European Food Safety Authority (EFSA) and other agencies have examined the validity behind these accusations towards artificial sweeteners, but they have always concluded that the claims are without substance. The EFSA assert that many of the suggested adverse effects have arisen because of misunderstandings, data dredging (pulling out select pieces of data that suit their hypothesis), and selective use of information. What they should be doing is trying to yield a balanced review of all the evidence on sweeteners, and this would entail a solid Randomised Controlled Trial (RCT).
Ruxton, C. (2014). Low calorie sweeteners : Role and benefits. Retrieved 27th October, 2014, from http://www.nutrition2me.com/images/free-view-articles/free-downloads/cnfvol.4no.2_sweetners.pdf