Don’t Eat The Vegetables!
Whoever managed to convince a large percentage of the public that consuming loads of fiber – from raw vegetables, grains, beans and other dietary sources – was a good idea for health generally and for digestion specifically, certainly pulled a fast one.
Wait a minute. Might it have been the same people who brought us the polyunsaturated seed oils and fish oils. The same people who marketed those products as ‘heart healthy’ and protective, and explained away increases in disease to be the result of saturated fat, cholesterol and sugar consumption.
Who is behind these advertisements, government findings, recommendations and official guidelines. Are they ‘scientific’? Is there a common thread binding them together?
Maybe some of the answers to these questions can be found in the words of Deep Throat – from the well known Watergate scandal film ‘All The President’s Men’ – who famously advised Robert Redford to ‘just follow the money.’
“Lack of fiber in the diet was first postulated in 1971 as the cause of diseases such as diverticulosis, hemorrhoids and colorectal cancer. Since then, partly due to widespread media publicity, it is now widely accepted that dietary fiber is a necessary component of a healthy diet and is required for normal bowel movement.”
In the real world however, the right responses in the debate over whether the consumption of more or less fiber is going to be beneficial or harmful, are not always quite as clear as has been made out.
In one study attached below, 63 patients with so called ‘idiopathic’ (i.e ‘we have no explanation’) constipation – with symptoms including ‘constipation, abdominal distension, pain or bloating, difficulty in evacuation with or without symptoms of rectal bleeding’ – enrolled to examine the effects of removing all dietary fiber, ‘including vegetables, cereals, fruits, wholemeal bread and brown rice’ on bowel movement regularity and other related issues.
“They were to continue their normal quantities of carbohydrates and proteins. Sieved fruit juices and clear vegetable soups were allowed…After 2 wk, patients were asked to continue on with as little fiber in their diet as they were comfortable with for the long term.”
The results at the 6 month follow-up showed a significant improvement in regularity, relative to the reduction in fiber.
On top of this, all other related symptoms improved relative to fiber reduction, and only resolved completely for those in the ‘no-fiber’ group. The study concluded that the ‘previous strongly-held belief about the application of dietary fiber to help constipation is but a myth.’
So are there any biologically valid explanations for all the confusion regarding the role of fiber in relation to healthy digestion and health in general?
Like many other aspects of diet and metabolism, this is not a black and white issue, and an appreciation of context will always be crucial for deeper understanding.
Whilst it is true that in some circumstances (which I will discuss further on) certain kinds of fiber can be more helpful than others, it is also often the case that consumption of greater amounts – and the wrong types – of fiber will end up being an important factor interfering with proper function, sometimes fueling disease.
Besides the fact that the most popular foods recommended for their fiber content are commonly made up of a variety of potentially toxic and harmful anti-nutritional, allergenic and even carcinogenic substances – many of which interfere with digestive function via suppression of metabolism and the reduction in effectiveness of digestive enzymes – it is often the fibers themselves, especially in excess, which are causing issues.
“The anti-nutritional factors can be defined as those substances generated in natural food substances by the normal metabolism of species and by different mechanisms (e.g. inactivation of some nutrients, diminution of the digestive process or metabolic utilization of feed) which exert effects contrary to optimum nutrition.”
Much of the fiber found in foods like beans, grains and vegetables – even some fruits – cannot be properly digested by humans, and as such end up being left for bacteria to feed on.
The overgrowth of bacteria throughout the intestine and the subsequent increase in endotoxin release – promotes other inflammatory substances (such as serotonin and estrogen) – and has been shown to suppress thyroid and energy systems and interfere with digestion.
As digestion is slowed there is often a build up of toxins, partly because of a reduction in the speed of evacuation, leaving waste materials in the system for longer than optimal periods of time. More time is also left for bacteria to feed on and ferment undigested foods allowing them to grow in number and move further up the intestine, promoting what can eventually become a vicious circle driven by endotoxin and a number of related inflammatory substances including serotonin and lactic acid.
“Intestinal inflammation alters the contractile activity of intestinal smooth muscle. Motility disorders of the gastrointestinal tract are…often associated with severe…inflammation. In addition, the motility disorders secondarily induce abnormal growth of the intestinal flora, and the resulting disturbance of this flora aggravates the pathogenesis of mucosal inflammation. This in turn aggravates the intestinal dysmotility; i.e., it is an inflammatory spiral.”
The slowing of digestion plays a big part in the re-absorption of estrogen and other harmful substances as a result of their failure to be properly eliminated, and this can then end up playing a big part in the promotion of worsening inflammatory conditions, and greater suppression of digestion.
“Experimental and observational data provide compelling biological evidence that frequent bowel motility is associated with increased excretion of estrogen in the stool and lower serum estrogen levels…we observed no association between bowel frequency and intakes of fiber-containing laxatives or dietary fiber.”
The bulking nature of excess fiber often fuels this issue not simply as a result of the feeding of bacteria, but also because of factors such as stool size build-up potentially further slowing movement and interfering with evacuation. Consuming some saturated fat (butter or coconut oil for instance) with even the potentially more harmful fibers can reduce bacterial interaction and improve the possibility that the fiber will assist with movement and waste removal.
“The role of dietary fiber in constipation is analogous to cars in traffic congestion. The only way to alleviate slow traffic would be to decrease the number of cars and to evacuate the remaining cars quickly. Should we add more cars, the congestion would only be worsened.”
Too much fiber intake can increase stool size to the point of stretching and irritating intestinal tissue, promoting further inflammation and the increased release of metabolically suppressive substances such as serotonin.
“Serotonin…can cause abdominal pain and discomfort, satiety, or nausea…promote intestinal inflammation…can have extra-alimentary actions such as influencing bone densitity and contributing to allergic airway inflammation.”
Digestive inhibition and the related rise in secretion of stress substances has been shown to interfere with blood sugar regulation, which can then lead to an increase in the release of the polyunsaturated free fatty acids from storage, which (on top of the PUFA content found in the fibrous foods) plays a significant role in the suppression of proper digestive function.
Although there are some fibers, such as in raw carrot for example, which can be very beneficial due to their anti-bacterial properties, in some cases reliance on fiber for improved bowel frequency can equate to a reliance upon a kind of irritation or toxin initiated flushing effect, rather than the result of a real improvement in bowel motility from an increase in metabolic function and the subsequent increase in digestive speed and efficiency.
This might be especially significant in circumstances where metabolic function has not yet improved, and where the removal of fiber might at first appear to slow things down, due to the irritation and stimulation effect having been removed. This can potentially (at least temporarily) lead to an overall worsening of symptoms and metabolic health issues. The safer fibers (as well as a few things with binding or laxative effects) can be particularly useful during this ‘transitional’ period, or just generally in order to help clean the intestines and remove toxic materials when there isn’t regularity.
Balanced against this is the potential for foods which are being pushed as a solution to issues of digestive slowing and constipation causing an increase in substances responsible for worsening of bowel inflammation related issues, possibly resulting in chronic diarrhea or fluctuations between the two extremes.
“…the 5-HT [serotonin] level has been shown to be altered in experimental intestinal inflammation and in IBD patients, and high levels of 5-HT have also been described in several inflammatory and diarrheal conditions.”
There generally isn’t a ‘one size fits all’ solution to metabolic issues which relate to digestion, and so from one perspective the use of fiber for stimulation and for a bulking effect can be part of a beneficial approach, helping move things along, promoting an overall improvement in elimination and an eventual metabolic recovery.
It seems more logical, however, that this might end up being the result if the fiber comes from a food which is safer, has less potential to cause bacterial overgrowth, and includes within it less of the substances which can either directly or indirectly suppress thyroid function and energy systems. Apart from the fiber in raw carrots and a few other things, fiber from well cooked potatoes has been shown to be reasonably safe for those who can handle it, and are not allergic to the nightshades.
When metabolism and digestion are already damaged however, even the most appropriate foods with the safest ingredients and fibers can be a big factor which leads to a worsening of the current situation, especially when consumed in too large quantities.
So what could possibly be the motivation behind the vast number of glowingly positive endorsements advocating the use of fiber as a healthy digestion promoting technique?
It certainly is a clever way to further promote the healthiness of products that provide a large portion of the profits for many big and powerful industries with significant economic and political importance.
There is also the issue of creating new industries out of what were formerly waste materials from existing production. In a sense, turning people into something like human rubbish tips and making them pay for the privilege.
There are many other possible explanations, some going beyond pure profit motive alone. No doubt, many I haven’t thought of.
Regardless, one effective approach for dealing with digestive issues – including constipation – might be one that experiments with a simple diet, limiting (and possibly even removing) most fiber, whilst at the same time gradually attempting to improve metabolism with sufficient protein from milk, cheese and gelatin, and plenty of sugar from sweet ripe juicy low fiber fruits or juice, honey and white sugar.
Exploring the use of some fibers with the antimicrobial saturated fats (sometimes combining with milk or cheese for the additional calcium which can help protect against bacteria) in order to improve motility when necessary, is also reasonable.
Chances are it’s impossible to come up with a solution to the digestive health issues of all people based on a set of rules that must be followed. Experimentation with different combinations of foods (and numerous other things) is necessary and what will work depends on individual metabolic issues. However because of the many misleading guidelines touted as scientific fact, it often ends up being a bit like a shot in the dark.
Even in an ideal scenario, the question regarding whether fiber is ‘good’ or ‘bad’ can probably not really be conclusively answered because of the different kinds of fiber and other variables and changing circumstances. Things that help for a while may stop working when conditions change.
Yes, certain types of fiber are more likely to be helpful as part of an experimental approach to healing – like the anti-microbial fiber in raw carrots or the anti-estrogenic substances safely available in very well cooked mushrooms – but healing can take time and unfortunately we do not live in a vacuum.
But there is a very powerful belief system still surrounding the idea that fiber is something we need for our digestive system to function properly and this often ends up being a hindrance for recovery or maintenance of health.
My mother is not the only person who has been exposed to decades worth of ‘roughage indoctrination’, and hidden inside this are elements of truth which can make the idea far more difficult to let go of when it is no longer serving you.
Even though unicorns might turn out to be mythological creatures, I do know of a world where it really is possible to fart rainbows.
See more here
Physiological modulation of intestinal motility by enteric dopaminergic neurons and the D2 receptor: analysis of dopamine receptor expression, location, development, and function in wild-type and knock-out mice.
Meme: by me