Comment by gumby
4 hours ago
There’s an enormous amount of data on this topic. So much I’ll just tell you to do a web search rather than pointing to some papers in is response: it’s just so pervasive and going back for decades.
Use a conventional search not an ai-generated summary as that will have influencer slop mixed in. Though oddly, I’ve never seen an anti-fibre influencer, but have seen lots of pro-fibre influencer posts!
> There’s an enormous amount of data on this topic.
FWIW, the evidence demonstrating that fibre is protective against colon cancer is limited, and when studies try to adjust for behavioural differences, the colon cancer reduction disappears.
Actual RCTs that randomly assigned subjects found no difference in polyp rates between high and low fibre diets.
For decades it was indeed widely observed that the people who ate a lot of fibre tended to have a lower incident rate. But the sort of person who has a high fibre diet almost always has a lot of other protective habits and norms: They're less likely to smoke, less likely to drink to excess, they tend to eat less red meat, they eat less sugar and UPFs, and so on.
As is often the case, these habits don't tend to happen in isolation, and this is where observational studies fail. So if you take someone with a lot of bad habits and supplement fibre, they'll have better cholesterol control, glycemic benefits, and of course regularity benefits, but it won't measurably move the needle on colon cancer rates.
This is all just conversational, but the current consensus is that fibre, or lack thereof, is not a contributor behind the rise in colon cancer among younger subjects. There are many suspected causes, all moving the needle enough that incidence rates jump.
> Actual RCTs that randomly assigned subjects found no difference in polyp rates between high and low fibre diets.
As far as I know the only RCT that fits that description is one looking at people who had already developed adenomas and then tested for reoccurrence.
An RCT actually designed to answer the question would need to last decades and just isn’t feasible.
There are a large multitude of studies that show a negative correlation between CRC and fiber intake even when adjusting for diet, exercise, BMI, income, alcohol consumption etc…
> but the current consensus is that fibre, or lack thereof, is not a contributor behind the rise in colon cancer among younger subjects.
There’s not good evidence to say it’s the sole or primary factor, but saying there’s consensus that is not a contributor is way too strong.
Thanks!