Monosodium glutamate and brain development in rats
What it found
In rats fed monosodium glutamate before birth and through 90 days of age, the authors found no evidence of harm to brain development.
The study was in animals, not people.
What they found
Animal and lab studies
Functional test results
Of the 21 functional tests, 4 were significant, involving 6 effects. Two of these were improvements, not deficits.
Swimming development
Two effects were on swimming development: one was an improvement and the other a minor delay that was not significant.
Active avoidance
Two effects were on active avoidance: one was a low-dose effect in females only, and the other a high-dose effect in males only. Neither was consistent.
Passive avoidance
One effect was on passive avoidance, but it was an improvement rather than a deficit.
Open-field rearing
The last effect was on open-field rearing, without the usual link to changes in movement.
What the authors conclude
“Thus, it can be concluded, as was done in 1979 and by the U.S. Food and Drug Administration who sponsored the study, that there is no evidence in these data that dietary MSG is developmentally neurotoxic, hence, the study provides no basis for the establishment of a NOAEL and changing the ADI for dietary MSG.”
Also in their conclusions
- They conclude that there is no evidence in these data that dietary monosodium glutamate is developmentally neurotoxic.
- They state that the study provides no basis for setting a no observable adverse effect level or changing the acceptable daily intake for dietary monosodium glutamate.
How it was done
The 1979 study had recently been cited as setting a level of monosodium glutamate with no observable adverse effect, which led to a change in the acceptable daily intake. The author re-evaluated the study because of this.
Sprague-Dawley rats were fed diets with 0, 1.7, 3.4, or 5.1% monosodium glutamate before conception, throughout pregnancy and nursing, and the young rats continued on the same diets until 90 days of age. About 18 to 20 litters were tested per dose. There were 21 functional tests with 36 measures, plus 10 body weight and tissue outcomes.
What it can’t tell you
- We summarised it from the abstract only.
- These are animal studies. They can't show what happens in people.
- The study cannot show whether monosodium glutamate affects brain development in humans.
Who paid
- Authors work at
- University of Cincinnati College of Medicine and Division of Neurology, USA
The paper
- Title
- A Test of Dietary Monosodium Glutamate Developmental Neurotoxicity in Rats: A Reappraisal
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Animals and lab studies
- Summarised from
- Abstract only
- Cite
- Vorhees CV (2018). A Test of Dietary Monosodium Glutamate Developmental Neurotoxicity in Rats: A Reappraisal. Annals of nutrition & metabolism. doi:10.1159/000494781PubMed 30508817DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error