In Vitro Effects of Twelve Food Additives on Gut Microbiome and Its Fibre Fermentation Capacity in Adults with Crohn's Disease in Remission and Healthy Controls.

Maltodextrin increased acetate production in both healthy controls and patients with Crohn's disease.

• Faeces from 6 healthy controls (HCs) and 6 patients with CD in clinical remission (Harvey Bradshaw Index < 5) were used.
• In vitro fermentation of a fibre mix with each of 12 food additives was performed.
• Short-chain fatty acids (SCFAs) were measured using gas chromatography.
• Maltodextrin also reduced butyrate production in healthy controls.

Turmeric increased acetate and butyrate production in healthy controls, while sodium sulphite reduced acetate production in healthy controls.

• These effects were observed only in the HC group, not in CD patients.
• SCFAs were measured using gas chromatography following in vitro faecal fermentation.
• The study used a fibre mix as the fermentation substrate alongside each additive.

Titanium dioxide increased microbiome Shannon α-diversity in both healthy controls and Crohn's disease patients, while carrageenan kappa increased Shannon α-diversity only in CD patients.

• Microbiome profiling was performed using 16S rRNA amplicon sequencing.
• Shannon α-diversity was used as the measure of within-sample microbial diversity.
• The differential effect of carrageenan kappa represents one of the modest health-status-specific differences observed.

Maltodextrin and polysorbate-80 induced significant shifts in microbiome structure (β-diversity) in both healthy controls and CD patients.

• Maltodextrin effects: HC: R2 = 6.8%, p = 0.001; CD: R2 = 5.1%, p = 0.004.
• Sodium sulphite also caused a significant β-diversity shift in healthy controls (HC: R2 = 6.9%, p = 0.001).
• β-diversity was assessed via 16S rRNA amplicon sequencing.

Maltodextrin significantly decreased the estimated absolute abundance of Escherichia-Shigella in CD patients, while sodium benzoate, potassium sorbate, and calcium propionate decreased Escherichia-Shigella abundance in healthy controls.

• Total bacterial load was measured with qPCR to enable estimation of absolute abundance.
• The differential effects on Escherichia-Shigella between groups represent a health-status-specific finding.
• 16S rRNA amplicon sequencing was used for microbiome profiling.

Faecalibacterium decreased in the presence of polysorbate-80 in both healthy controls and CD patients, and also decreased in the presence of maltodextrin in the CD group.

• Faecalibacterium is a genus associated with gut health and anti-inflammatory properties.
• The decrease with polysorbate-80 was observed across both participant groups.
• The decrease with maltodextrin in CD patients represents a group-specific finding.

Total bacterial load decreased with polysorbate-80, potassium sorbate, maltodextrin, and calcium propionate in both healthy controls and CD patients.

• Total bacterial load was measured using quantitative PCR (qPCR).
• Xanthan gum additionally decreased total bacterial load in healthy controls only.
• These reductions suggest antimicrobial or microbiome-suppressive properties of these additives under in vitro conditions.

The study used an in vitro faecal fermentation model with 12 food additives including calcium propionate, carboxymethylcellulose, carrageenan kappa, cinnamaldehyde, maltodextrin, polysorbate-80, potassium sorbate, sodium benzoate, sodium sulphite, titanium dioxide, turmeric, and xanthan gum.

• Faeces were obtained from 6 healthy controls and 6 patients with CD in clinical remission (Harvey Bradshaw Index < 5).
• Each additive was fermented with a fibre mix to assess both SCFA production and microbiome effects.
• Analyses included gas chromatography for SCFAs, 16S rRNA amplicon sequencing for microbiome profiling, and qPCR for total bacterial load.

Overall, differences in food additive effects on the gut microbiome between CD patients in remission and healthy controls were only modest.

• Some additive effects were observed in both groups (e.g., maltodextrin on acetate, polysorbate-80 on Faecalibacterium and bacterial load).
• A limited number of effects were group-specific, such as carrageenan kappa increasing α-diversity only in CD, and turmeric increasing SCFAs only in HCs.
• The authors concluded that health status had only a modest influence on the direction or magnitude of additive effects.