The results of the largest, long-term trial to date, published in 1999, also suggest that, contrary to popular belief, high dietary fibre intake does not protect against colorectal cancer.  Researchers at HarvardMedical School and the Dana-Farber Cancer Institute, both in Boston, Massachusetts, studied 88,757 women over sixteen years. They say: 
'no significant association between fiber intake and the risk of colorectal adenoma was found'. But there was what they call an 'unexpected' finding, in that, according to their data, a high consumption of vegetable-derived fiber was actually 'associated with a significant increase (35%) inthe risk of colorectal cancer'. They conclude 'Our data do not support the existence of an important protective effect of dietary fiber against colorectal cancer or adenoma'.