Unexpected Side Effects of Indigestible Compounds Used in Foodstuffs: Saccharin, Maltodextrin, Trehalose et alia

An article in the opinion section of the NYT describes the unexpected side effects of certain compounds used in the manufacture of modern foodstuffs– chemicals like trehalose, saccharin, and Tween-80.  These synthetic (in most cases) chemicals are used for many purposes, primarily as sweet-tasting substitutes for sugar, emulsifiers, and additives designed to lengthen the shelf-life of otherwise perishable foods.  The following post summarizes the information that forms the basis for this NYT opinion article.

First, trehalose appears to select for particularly aggressive forms of the toxic bacterium, Clostridium perfringens, which causes a potentially lethal diarrhea in humans treated with antibiotics to which they are resistant (primarily clindamycin, cephalosporins, and fluoroquinolones.)  This was not a problem when trehalose was too expensive to be added to foods.  However, perhaps twenty-five years ago, a new method of synthesis of trehalose was developed which dramatically lowered the cost (from $700 a kilogram to $3.)  Trehalose is valued because it has the ability to retain large amounts of water and keep foods moist on the shelf– it is used by some microbes to prevent damage from freezing.

The presence of even low concentrations of trehalose selects for a virulent strain of C. difficile which can cause severe or even lethal diarrhea, particularly after competing microbes have been removed by the administration of antibiotics.  Since the introduction of large quantities of trehalose to foodstuffs, a new “epidemic” strain of C. difficile has appeared and dramatically increased the incidence of toxic diarrhea.  This strain is often resistant to the new fluoroquinolone antibiotics such as ofloxacin, ciprofloxacin, and levofloxacin.  A study in Nature shows that mice fed trehalose are more often killed when they are challenged with C. difficile strains that have this new ability to metabolize trehalose.

Second, emulsifiers like polysorbate-80 and carboxymethylcellulose can thin the mucus barrier that lines our intestines and can induce gut microbes to produce proteins that cause inflammation.  This inflammation is associated with metabolic syndrome, a form of obesity that is a precursor to diabetes.   Maltodextrin is a food thickener that does this, plus it enhances the growth of a strain of Escherichia coli that is associated with Crohn’s disease, a chronic inflammatory gut condition that is extremely debilitating.

Third, artificial sweeteners like saccharin and sucralose that taste sweet but are supposed to contribute nothing to our calorie counts, can be metabolized by some microbes.  Studies have shown that saccharin and other artificial sweeteners induce glucose intolerance by altering the gut microbiome (our intestinal bacteria.)

The bottom line is that, when we consume chemicals that we cannot metabolize, this selects for the growth of intestinal microbes that can do the job for us.  A classic example is the presence of gut microbes that can metabolize seaweed constituents in Japanese people.  Most world populations do not normally eat seaweed, and they cannot digest it to generate food energy.  The Japanese people, however, have long eaten seaweed as a significant part of their diets, and their gut microbes have adapted by evolving the ability to digest seaweed.  It is likely that this has occurred quite simply, by the co-ingestion of microbes living on seaweed that are able to break it down.  As a result, people with this population of microbes gain calories and nutrition from consuming seaweed, whereas people without it miss out.

This information may make you less likely to consume foods containing these chemicals.  That would be logical, but it may be difficult to avoid some of these things and still eat ice cream or drink soda pop.  The NYT opinion article also recommends that you consume more soluble fiber, in foods such as “nuts, legumes, and vegetables.”  I heartily endorse this recommendation.  In addition, you may still be able to eat ice cream if you make it yourself or find a brand that does not contain any of these chemicals.

(photo courtesy of pixabay.com and Alexas_Fotos)