Geha R S, Beiser A, Ren C, Patterson R, Greenberger P A, Grammer L C, Ditto A M, Harris K E, Shaughnessy M A, Yarnold P R, Corren J, Saxon A
Division of Immunology, Children Hospital and Department of Pediatrics, Harvard University, Boston, MA, USA.
J Allergy Clin Immunol. 2000 Nov;106(5):973-80. doi: 10.1067/mai.2000.110794.
The frequency of reactions reported to occur after the consumption of monosodium glutamate (MSG) is the subject of controversy.
We conducted a multicenter, multiphase, double-blind, placebo-controlled study with a crossover design to evaluate reactions reportedly caused by MSG.
In 3 of 4 protocols (A, B, and C), MSG was administered without food. A positive response was scored if the subject reported 2 or more symptoms from a list of 10 symptoms reported to occur after ingestion of MSG-containing foods within 2 hours. In protocol A 130 self-selected reportedly MSG-reactive volunteers were challenged with 5 g of MSG and with placebo on separate days (days 1 and 2). Of the 86 subjects who reacted to MSG, placebo, or both in protocol A, 69 completed protocol B to determine whether the response was consistent and dose dependent. To further examine the consistency and reproducibility of reactions to MSG, 12 of the 19 subjects who responded to 5 g of MSG but not to placebo in both protocols A and B were given, in protocol C, 2 challenges, each consisting of 5 g of MSG versus placebo.
Of 130 subjects in protocol A, 50 (38. 5%) responded to MSG only, 17 (13.1%) responded to placebo only (P <. 05), and 19 (14.6%) responded to both. Challenge with increasing doses of MSG in protocol B was associated with increased response rates. Only half (n = 19) of 37 subjects who reacted to 5 g of MSG but not placebo in protocol A reacted similarly in protocol B, suggesting inconsistency in the response. Two of the 19 subjects responded in both challenges to MSG but not placebo in protocol C; however, their symptoms were not reproducible in protocols A through C. These 2 subjects were challenged in protocol D 3 times with placebo and 3 times with 5 g of MSG in the presence of food. Both responded to only one of the MSG challenges in protocol D.
The results suggest that large doses of MSG given without food may elicit more symptoms than a placebo in individuals who believe that they react adversely to MSG. However, neither persistent nor serious effects from MSG ingestion are observed, and the responses were not consistent on retesting.
据报道，食用味精（MSG）后出现反应的频率存在争议。
我们开展了一项多中心、多阶段、双盲、安慰剂对照且采用交叉设计的研究，以评估据报道由味精引起的反应。
在4个方案（A、B和C）中的3个方案里，味精是在无食物的情况下给予的。如果受试者在摄入含味精食物后2小时内，从一份列出的10种症状清单中报告出2种或更多症状，则记为阳性反应。在方案A中，130名自行选择的据报道对味精有反应的志愿者在不同日期（第1天和第2天）分别接受5克味精和安慰剂的激发试验。在方案A中对味精、安慰剂或两者都有反应的86名受试者中，69名完成了方案B，以确定反应是否一致且呈剂量依赖性。为了进一步检验对味精反应的一致性和可重复性，在方案C中，对在方案A和方案B中对5克味精有反应但对安慰剂无反应的19名受试者中的12名进行了2次激发试验，每次试验均包含5克味精与安慰剂的对比。
在方案A的130名受试者中，50名（38.5%）仅对味精有反应，17名（13.1%）仅对安慰剂有反应（P <.05），19名（14.6%）对两者都有反应。方案B中用递增剂量的味精进行激发试验与反应率增加相关。在方案A中对5克味精有反应但对安慰剂无反应的37名受试者中，只有一半（n = 19）在方案B中的反应类似，这表明反应存在不一致性。在方案C中，19名受试者中有2名在两次味精激发试验中均有反应但对安慰剂无反应；然而，他们的症状在方案A至C中不可重复。在方案D中，这2名受试者在有食物的情况下接受了3次安慰剂激发试验和3次5克味精激发试验。两人在方案D中仅对一次味精激发试验有反应。
结果表明，对于认为自己对味精有不良反应的个体，无食物时给予大剂量味精可能比安慰剂引发更多症状。然而，未观察到因摄入味精产生的持续或严重影响，且再次测试时反应并不一致。
