The effect of sodium benzoate on the gut microbiome across age groups

Authors: Scarino Lemons, Johanna; Firrman, Jenni; Mahalak, Karley; Liu, Lin; Narrowe, Adrienne; HIGGINS, STEPHANIE - The Children'S Hospital Of Philadelphia; MOUSTAFA, AHMED - The Children'S Hospital Of Philadelphia; BAUDOT, AURELIEN - Cryptobiotix; DEYAERT, STEF - Cryptobiotix; VAN DEN ABBEELE, PIETER - Cryptobiotix

Submitted to: Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2025
Publication Date: N/A
Citation: N/A
DOI: https://doi.org/10.3390/foods14172949

Interpretive Summary: Consumers continue to be concerned about how food additives may impact their health. This study sought to explore the effect of the widely used food preservative sodium benzoate on the gut microbiota of individuals aged infants to older adults. This novel study treated bacterial communities with a dose ten times higher than the maximum dose an individual is likely to consume in a day and still only elicited minor changes. There was almost no effect when individual age groups were considered separately, and even when all donors were considered together there were only a few significant changes. The most striking results were a significant decrease in the amount of E. coli and a significant increase in the amount of butyrate produced. On their own these are often considered beneficial changes to a gut microbial community suggesting that even at levels higher than those normally consumed, sodium benzoate does not have a detrimental effect on the gut microbiome.

Technical Abstract: The food additive sodium benzoate (SB) has been used for decades as an antimicrobial to prevent food spoilage. SB has been deemed to pose no risk to human health when consumed at levels under 5 mg/kg body weight per day, however when many of the supporting studies were conducted, the importance of the gut microbiome to human health was not yet appreciated. Given SB’s known antimicrobial qualities, it is important to assess the effect of this food additive on the human gut microbiome. The ex vivo SIFR® (Systemic Intestinal Fermentation Research) technology was used to test the effect of SB on microbial communities from 24 donors, aged infants to older adults. A dose of 3.5 g/L SB elicited a drop in the Pseudomonadota phylum for multiple age groups but did not alter the alpha or beta diversity within any of these groups. This was accompanied by changes in the functional outputs that included an overall rise in butyrate and a drop in propionate production. This higher butyrate correlates with an increase in the abundance of several known butyrate producers in the presence of SB, although the genetic potential for its production in the community did not change. Overall, despite using a dose ten times higher than the accepted daily intake limit, the effect on the gut microbiome was minimal.