The fiber story began with a guy named Burkitt, he compared the pattern of diseases in African hospitals to western diseases in the 1950’s and 60’s.
So the story of fiber begins with this guy named Denis Burkitt who was a surgeon in the 1950’s and 1960’s and he went to Africa, to Tanzania and there he described something called Burkitt’s lymphoma which doesn’t have to do with fiber, but then he also noticed that people in Africa did not have the same incidence of diverticulosis that people had in Britain at the time, and he was very curious about this and so he tried to understand what was going on, as any curious physician would.
Diverticulosis is a condition of deformation of blind loops in the colon where the mucousal layer out-pouches, basically pushes out, through the musculary mucousa, forming these blind pouches, they’re called diverticuli and they’re often asymptomatic. They’re quite present and very common in the population, above the age of 50 years old, approximately 60-70% of the population has diverticulosis, which is the formation of these blind little pouches in the colon.
It’s not a good thing because these pouches can be the source of lower GI bleeding which can be quite life threatening or they can become full of food matter and occluded at the base of the diverticulum and form diverticulitis, which is a condition where the whole diverticulum gets walled off, it forms pus and it’s like a little mini appendix.
And that’s basically how you can think of diverticuli, it’s like all these appendices. We have an appendix in the lower right quadrant and that’s in the cecum, it’s a structure that may have some immunologic function with these pyres patches, and basically a blind tube, so when the appendix gets stuffed up with things or if the appendix gets closed off at the base it forms appendicitis which is when it gets swollen, infected and full of pus.
Well these little diverticuli can do the same thing, and so this incidence of diverticulosis was being noted in Britain at the time and Burkitt went to Africa and saw the people there didn’t have the same amount of diverticulosis that people in Britain did and he thought ‘What is going on here, what is the difference in what people in Africa are doing?!’ And [the people in Africa] were doing A LOT of things differently, but we now know in retrospect that he mistakenly thought that it had to do with fiber!
They were eating a lot of fibrous foods, he described these very large bowel movements they were having and he thought ‘Ah! that’s it, it’s fiber! It’s all of the fiber in their diet that’s protecting them from diverticulosis!’
BUT! The problem is that when we have studied this in the west it doesn’t seem to be the case at all!!
And this is when people really start to have their minds blown because if you go to your doctor and you have diverticulosis, they’re going to tell you to eat a high fiber diet, because unfortunately most of the physicians in the world don’t understand the research and they don’t understand that this isn’t the case at all.
There’s no evidence to suggest that fiber protects against diverticulosis, as Burkitt suggested, it’s sort of an old fairy tale that’s very hard to correct and there’s actually several studies that would suggest the reverse.
For example, there’s a study in 2019 in the journal of Gastroenterology, the title of the study is ‘A High Fiber Diet Does Not Protect Against Asymptomatic Diverticulosis’
This was a study of 2,100 participants and they all had colonoscopy from 1998 to 2010, with the colonscope they looked for the presence of diverticuli. They then did a survey to see how much fiber people were eating in their diet.
The results were shocking to the researchers (keep in mind this study is from 2012 so it’s not that old, but fairly recent) and the idea was that the more fiber people were consuming, the more diverticulosis someone had! This is completely counter to what people were thinking!
So not only does fiber not have a protection effect against diverticulosis but in this study there’s a harmful association!
Now we can’t say that the fiber caused the diverticulosis, but it’s pretty clear that the presence of fiber was not protective against diverticulosis as people would suggest!
There’s also a 2013 study clinical in gastroenterology and hepatology, “Constipation and A Low Fiber Diet Are Not Associated with Diberticulosis”
This is a cross sectional study, which was colonoscopy based, that showed that neither constipation nor a low fiber diet was an increased risk of diverticulosis.
So this one again puts another nail in the coffin, that fiber is protective against diverticulosis, because a low fiber diet was not associated with diverticulosis, and the study showed that constipation was not associated with diverticulosis.
Source: Saladino, Paul, guest. “Part 39 – Paul Saladino, MD on Everything You Thought You Knew About Food Might Be Wrong” Peak Human, 2 May 2019. https://peakhuman.libsyn.com/part-39-paul-saladino-md-on-everything-you-thought-you-knew-about-food-might-be-wrong