Benzoic acid and how the body processes it in people and rats
What it found
People and rats process benzoic acid in very similar ways, and children handle it much like adults.
The authors say this means the daily intake limit could be doubled from 5 to 10 mg per kg of body weight.
What they found
Studies in people
Children process it like adults
Clinical studies show that children over one year old absorb and clear benzoic acid in much the same way as adults. Newborns may process it more slowly, but they have very little exposure to it through food.
High medical doses tolerated
When used as a medicine, people including children took doses up to 500 mg per kg of body weight per day without apparent harm. Unwanted effects like vomiting only appeared after accidental exposures around 800 mg per kg per day and stopped when the exposure ended.
Liver problems made no difference
Patients with poor liver function were given sodium benzoate at amounts 14 to 28 times higher than the current daily intake limit. The authors report no treatment-related unwanted effects in these patients.
Animal and lab studies
Human liver tissue works faster
In lab tests using liver samples, human tissue broke down benzoic acid about 2.5 times faster than rat liver tissue. This suggests people may actually process the preservative more efficiently than rats do.
Studies in people and animals
Similar processing in people and rats
After being swallowed, benzoic acid is quickly and fully absorbed in both people and rats. Both species break it down in the liver using the same chemical pathway and clear almost all of it in urine within 6 to 24 hours.
What the authors conclude
- They conclude that the total uncertainty factor used to set the daily intake limit can be reduced from 100 to 50 based on the available data.
- They advise that the acceptable daily intake for benzoic acid and its salts should be increased from 0-5 mg per kg of body weight to 0-10 mg per kg of body weight.
- They call for more research on how newborns and other potentially sensitive groups process benzoic acid before further adjustments are made.
How it was done
The current daily intake limit for benzoic acid was set in 1962 using a large safety margin because scientists lacked detailed data. Since then, many more studies on how people and animals process this preservative have become available, so the authors wanted to see if that margin could be updated.
They reviewed published studies on how benzoic acid is taken in, moved around, broken down, and cleared by the body in humans and rats. They looked at clinical trials involving healthy adult volunteers, children with genetic conditions, and patients with liver problems who received sodium benzoate as medicine. They compared blood measurements between species to calculate new adjustment factors for setting intake limits.
What it can’t tell you
- Most of the clinical studies in people were small and observational rather than controlled experiments, so they cannot prove cause and effect.
- The animal and lab tissue results suggest people process benzoic acid efficiently, but they cannot perfectly predict what happens in every person eating preserved foods.
- The medical doses studied in people were much higher than typical food exposures, so the findings may not directly reflect everyday dietary intake.
Who paid
- Authors work at
- 20 University Road, USA
The paper
- Title
- Pharmacokinetic data reduce uncertainty in the acceptable daily intake for benzoic acid and its salts
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Zu K, Pizzurro DM, Lewandowski TA, Goodman JE (2017). Pharmacokinetic data reduce uncertainty in the acceptable daily intake for benzoic acid and its salts. Regulatory toxicology and pharmacology. doi:10.1016/j.yrtph.2017.07.012Free full textPubMed 28720346DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error