营销话术证据 A · 指南级
味精 (MSG) 有毒 (中餐馆综合征)
真相
源于 1968 年一封无对照来信; Geha 2000 双盲挑战仅 2.3% 反应且不可复现; 谷氨酸与番茄、母乳中的同一分子, 正常餐食剂量安全。
机制速览
Kwok 那封信之后几十年，研究者用双盲、安慰剂对照的方式反复检验吃味精会不舒服这个说法。结论很一致：在正常吃饭的量下，测不出来。
来源（4）
- Geha, R. S., Beiser, A., Ren, C., et al. (2000). Review of alleged reaction to monosodium glutamate and outcome of a multicenter double-blind placebo-controlled study. Journal of Nutrition, 130(4S Suppl), 1058S-1062S. Double-blind placebo-controlled challenges failed to reliably reproduce MSG symptoms at dietary doses. Note: the id says JACI but this record is the J Nutr summary (PMID 10736382); the full trial report is geha-2000-msg-multicenter-challenge. Summary abstract: a multicenter double-blind placebo-controlled challenge in 130 people who reported MSG reactions; large doses given without food may elicit more symptoms than placebo, but responses were infrequent, inconsistent and not reproducible, and were not seen when MSG was given with food (abstract, PMID 10736382).
- Raiten, D. J., Talbot, J. M., & Fisher, K. D. (Eds.). (1995). Analysis of adverse reactions to monosodium glutamate (MSG), report prepared by FASEB for the U.S. FDA. Journal of Nutrition, 125(11), 2891S-2906S. Concluded MSG is generally safe at normal dietary intake. PubMed indexes the executive summary (PMID 7472671) without an abstract and the report text could not be re-read (publisher page blocked, 2026-09-25); FDA's MSG Q&A (fda-msg-qa) summarises this report's finding of transient, mild symptoms in some sensitive people after 3 g or more without food.
- Geha, R. S., Beiser, A., Ren, C., Patterson, R., Greenberger, P. A., Grammer, L. C., et al. (2000). Multicenter, double-blind, placebo-controlled, multiple-challenge evaluation of reported reactions to monosodium glutamate. Journal of Allergy and Clinical Immunology, 106(5), 973-980. 130 self-selected people who reported MSG reactions were challenged with 5 g of MSG and with placebo without food (protocol A): 50 (38.5%) responded to MSG only, 17 (13.1%) to placebo only and 19 (14.6%) to both. Rising doses raised response rates, but only 19 of 37 MSG-only responders reacted the same way on retest; the 2 people who then responded to MSG but not placebo twice were challenged 3 times each with 5 g of MSG and with placebo in the presence of food, and each responded to only one MSG challenge. Conclusion: large doses without food may elicit more symptoms than placebo in people who believe they react, but no persistent or serious effects were seen and responses were not consistent on retesting (abstract, PMID 11080723).
- U.S. Food and Drug Administration. (2026). Questions and answers on monosodium glutamate (MSG) (content current as of 17 July 2026). FDA considers the addition of MSG to foods 'generally recognized as safe' (GRAS). Adverse event reports led FDA to ask FASEB to examine MSG safety in the 1990s; FASEB's report concluded that MSG is safe, and identified short-term, transient and generally mild symptoms (headache, numbness, flushing, tingling, palpitations, drowsiness) that may occur in some sensitive individuals who consume 3 grams or more of MSG without food; consuming more than 3 grams of MSG without food at one time is unlikely. An average adult eats about 13 g of glutamate a day from food protein, against about 0.55 g a day of added MSG (Q&A page, read 2026-09-25).