Low folate protective against colon cancer?

Ed Giovannucci and his team have long touted the protective effects of dietary folate for colon cancer -- however in this epub, he presents three nested case-controlled studies that suggests exactly the opposite -- the findings suggest that folate intake doesn't directly determine plasma folate levels (meaning all those dietary questionnaire studies that were apparently validated for folate might be called into question...) -- and that in this "prospective" study, low folate was actually protective against colon cancer.  I'm thinking that this study just opened up a whole load of new questions (but ones that I already had anyway, so I'm glad to see it!) - you can read about it here --

Plasma folate, methylenetetrahydrofolate reductase (MTHFR), and colorectal cancer risk in three large nested case-control studies.