Sulfites inhibit the growth of four species of beneficial gut bacteria at concentrations regarded as safe for food

Sulfites and other preservatives are considered food additives to limit
bacterial contamination, and are generally regarded as safe for
consumption by governmental regulatory agencies at concentrations up to
5000 parts per million (ppm). Consumption of bactericidal and
bacteriostatic drugs have been shown to damage beneficial bacteria in
the human gut and this damage has been associated with several diseases.
In the present study, bactericidal and bacteriostatic effects of two
common food preservatives, sodium bisulfite and sodium sulfite, were
tested on four known beneficial bacterial species common as probiotics
and members of the human gut microbiota. Lactobacillus species casei, plantarum and rhamnosus, and Streptococcus thermophilus
were grown under optimal environmental conditions to achieve early log
phase at start of experiments. Bacterial cultures were challenged with
sulfite concentrations ranging between 10 and 3780 ppm for six hours. To
establish a control, a culture of each species was inoculated into
media containing no sulfite preservative. By two hours of exposure, a
substantial decrease (or no increase) of cell numbers (based on OD₆₀₀
readings) were observed for all bacteria types, in concentrations of
sulfites between 250–500 ppm, compared to cells in sulfite free media.
Further testing using serial dilution and drop plates identified
bactericidal effects in concentrations ranging between 1000–3780 ppm on
all the Lactobacillus species by 4 hours of exposure and bactericidal effects on S. thermophilus in 2000ppm NaHSO₃ after 6 hours of exposure.

Food additive found in candy, gum could alter digestive cell structure and function: Small intestinal cells hindered by chronic exposure to common food additive -- ScienceDaily

"The ability of small intestine cells to absorb nutrients and act as a barrier to pathogens is 'significantly decreased' after chronic exposure to nanoparticles of titanium dioxide, a common food additive found in everything from chewing gum to bread, according to new research."



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Common food additive promotes colon cancer in mice

 In this study, the team fed mice with two very commonly used emulsifiers, polysorbate 80 and carboxymethylcellulose, at doses seeking to model the broad consumption of the numerous emulsifiers that are incorporated into the majority of processed foods. Researchers observed that consuming emulsifiers drastically changed the species composition of the gut microbiota in a manner that made it more pro-inflammatory, creating a niche favoring cancer induction and development. Alterations in bacterial species resulted in bacteria expressing more flagellin and lipopolysaccharide, which activate pro-inflammatory gene expression by the immune system.
When using a well established model of colorectal cancer, the researchers observed that dietary emulsifier consumption was sufficient to make the animals more susceptible to developing colonic tumors because this created and maintained a pro-inflammatory environment associated with an altered proliferation/apoptosis (cell death) balance. The researchers observed that enhanced tumor development was associated with an altered intestinal microbiota, characterized by an increased pro-inflammatory potential."

Widely used food additive promotes colitis, obesity and metabolic syndrome, research shows

Emulsifiers, which are added to most processed foods to aid texture and extend shelf life, can alter the gut microbiota composition and localization to induce intestinal inflammation that promotes the development of inflammatory bowel disease and metabolic syndrome, new research shows.
Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, afflicts millions of people and is often severe and debilitating. Metabolic syndrome is a group of very common obesity-related disorders that can lead to type-2 diabetes, cardiovascular and/or liver diseases. Incidence of IBD and metabolic syndrome has been markedly increasing since the mid-20th century.
The team fed mice two very commonly used emulsifiers, polysorbate 80 and carboxymethylcellulsose, at doses seeking to model the broad consumption of the numerous emulsifiers that are incorporated into almost all processed foods. They observed that emulsifier consumption changed the species composition of the gut microbiota and did so in a manner that made it more pro-inflammatory. The altered microbiota had enhanced capacity to digest and infiltrate the dense mucus layer that lines the intestine, which is normally, largely devoid of bacteria. Alterations in bacterial species resulted in bacteria expressing more flagellin and lipopolysaccharide, which can activate pro-inflammatory gene expression by the immune system.