t that meat (especially red meats), can lead to the production of the very same protein–derived toxins within the gastrointestinal tract.
But, rather than needing to adhere to a strict vegetarian regime, recent research indicates, that if we consume certain protective nutritional elements, we may be able to largely eliminate the formation of protein–derived toxins from a high–protein diet.
To boot, such protective elements, namely, soluble fiber and resistant starch, not only eliminate protein–derived toxins – they can actually lead to the production of several protective elements by selectively feeding the “good” bacteria in our gastrointestinal tracts.
Soluble Fiber and Resistant Starch
As recently as several decades ago, scientists still thought of dietary fiber (and resistant starch – a unique type of dietary fiber) merely as the “inert” indigestible portions of plant–based foods. Even by the 1960’s when British surgeon, Denis Burkitt and colleagues coined the “fiber hypothesis” – the idea that high fiber foods may help to prevent colon cancer and other diseases of modern civilization – the beneficial effects of fiber were still simplistically assumed to involve fiber’s well–known effect of improving regularity.
But, while recent studies have failed to show a clear link between overall fiber intake and risk of gastrointestinal cancer. . .
. . .other studies have shown that certain types of fiber may be particularly protective in this regard:
So, rather than lumping all types of dietary fiber under one umbrella, some thinking scientists have begun to explore the varied effects of different types of fiber. As a result, the dietary fibers now suspected to be the most protective against protein–toxins, and the cancerous changes they cause, are the select few dietary fibers which are able to support the production of beneficial colonic flora (i.e. our “good” intestinal bacteria) – soluble fiber and resistant starch.
As we wrote about in the above–linked blog article, fermentable fibers feed beneficial bacteria which, in turn, produce a protective short–chain fatty acid called butyrate as a natural byproduct of their metabolism.
And, not only do these bacteria produce butyrate, which helps to nourish and protect the cells of the colon, but, as it turns out, these same beneficial bacteria are able to significantly reduce the production of protein–based toxins, as was found in this study:
Quote from the above study:
These results suggest that RS (resistant starch) significantly attenuates the accumulation of potentially harmful byproducts of protein fermentation in the human colon.
In fact, It’s likely to be our beneficial intestinal flora (and not just the fiber itself) which neutralizes the production of toxic metabolites from dietary protein.
As mentioned above, some of the protein we eat is able to travel all the way to the colon without being digested or absorbed. In the presence of a low–fiber diet, relatively “bad” bacteria will predominate in the colon, and these bacteria are able to metabolize this protein into the previously–mentioned toxic substances such as phenols, cresols, indoles, amines and ammonia.
But, on the other hand, if we supply our good bacteria with abundant amounts of soluble fiber/resistant starch, they (and not the bad bacteria) use the protein to grow and flourish in the intestines.
In other words, in the presence of certain types of fiber, beneficial bacteria are able to metabolize the nitrogen–containing components of undigested protein for their growth – thus simultaneously lowering the burden of toxic metabolites, (phenol, cresol, and ammonia); while increasing the production of beneficial substances like butyrate and other short chain fatty acids.
Scientists call the beneficial bacteria in our colon a “nitrogen sink” – meaning, a biomass which is able to metabolize nitrogen compounds (proteins) towards beneficial ends instead of toxic ones. While it often goes unrecognized, this natural form of “bioremediation” represents a stunning example of biological synergy, essential to our optimal hea