Monosodium glutamate 'allergy': menace or myth?

Area of Science:

• Food science
• Clinical immunology
• Toxicology

Background:

• Monosodium glutamate (MSG) is a common food additive known for flavor enhancement.
• Anecdotal reports and early studies suggested MSG causes various symptoms, termed 'Chinese restaurant syndrome'.
• Concerns include potential links to asthma, urticaria, angio-oedema, and rhinitis.

Purpose of the Study:

• To critically review the scientific literature on the role of MSG in the 'Chinese restaurant syndrome'.
• To evaluate the evidence linking MSG ingestion to allergic-type reactions such as asthma, urticaria, angio-oedema, and rhinitis.

Main Methods:

• Comprehensive literature review of studies investigating MSG and associated symptoms.
• Critical appraisal of the quality and consistency of evidence from clinical studies and anecdotal reports.

Main Results:

• Despite historical concerns, decades of research have not established a clear or consistent relationship between MSG consumption and symptom development.
• No definitive evidence supports MSG as a primary cause for conditions like asthma, urticaria, angio-oedema, or rhinitis.

Conclusions:

• The available scientific evidence does not support a causal link between dietary MSG and the 'Chinese restaurant syndrome' or specific allergic-type symptoms.
• Further high-quality research has not substantiated the initial claims regarding MSG's adverse effects.