Study title and authors:
Monosodium -glutamate-induced asthma
This paper can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/3312372
This study investigated the asthma-provoking potential of the widely used flavor enhancer, monosodium L-glutamate (MSG). The study was a single-blind, placebo-controlled trial and included 32 subjects with asthma, a number of whom suffered severe asthma after Chinese restaurant meals or similarly spiced meals. The subjects received an additive-free diet for five days before receiving increasing doses of MSG from 0.5 gm to 5.0 gm.
The study found:
(a) Seven subjects developed asthma and symptoms of the Chinese restaurant syndrome one to two hours after ingestion of MSG.
(b) Six subjects did not develop symptoms of Chinese restaurant syndrome, and their asthma developed 6 to 12 hours after ingestion of MSG.
Allen concluded: "These challenge studies confirm that MSG can provoke asthma. The reaction to MSG is dose dependent and may be delayed up to 12 hours, making recognition difficult for both patient and physician".