One of the reasons put forward for not adding folate to bread is the perception that this will lead to a rise in some forms of cancer (specifically, prostate & colo-rectal cancer). The Science Media Centre has posted a commentary from Dr Murray Skeaff, who's the Professor of Human Nutrition down at Otago. He discusses the results of a meta-analysis of studies looking at the impact of folate on human health. Such studies [look] at the totality of the scientific evidence. It’s state of the art — the highest quality of analysis that there is. And on the basis of that evidence, he concludes that adding folate to food will not result in an elevated risk of cancer.