It was a review or meta analysis. There was no criteria for acceptance. It’s just 2 random doctors cherry picking studies. The authors refer to it as an editorial and not a meta analysis for that reason. The language even sounds like a newspaper editorial. They make far too many unsupported assertions for an academic paper.
It’s also 20 years out of date. And we’ve had 2 decades of additional research.
>It is possible…
Of course it’s possible there’s a hidden confounder. That’s possible with literally every single observational study.
A sufficient RCT in this case is essentially impossible and likely unethical.
But you failed to read the conclusion that
> Our results indicate a 10% reduction in risk of colorectal cancer for each 10 g/day intake of total dietary fibre and cereal fibre and a about a 20% reduction for each three servings (90 g/day) of whole grain daily, and further reductions with higher intake. These findings thus have important public health implications. Our results provide further support for public health recommendations to increase the intake of dietary fibre in the prevention of colorectal cancer.
Despite the fact that it may be wrong.
Read the other 4 very large meta studies.
Read the statements from essentially every relevant heath authority.
Read the theoretical science.
Of course it’s possible that there are hidden confounders. But the preponderance of the evidence is that high fiber == less colon cancer.
Specifically:
1. We don’t know for sure what the relationship between fiber and CRC is, and we likely can’t.
2. The majority of studies that correct for lifestyle and diet still show a correlation.
3. There are plausible explanatory mechanisms.
4. The most likely explanation is that there is some protective effect.
There is broad consensus among Doctors, health agencies, and researchers that the above are true.