The artificial sweetener aspartame is once again the subject of controversy following research indicating it may cause cancer.
A long-term, large-scale study of the effect of aspartame on 1,800 rats showed that aspartame caused cancer of the kidney, and of the peripheral nerves in the head. Earlier data from the same study linked aspartame to a greater risk of leukemias and lymphomas, even at doses very close to what is considered the acceptable daily intake for humans.
The manufacturers of the sweetener have challenged the study, claiming that the results are not statistically significant, and that regulatory bodies around the world have concluded that aspartame is safe.