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Query: UMLS:C0018681 (headache)
56,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Monosodium glutamate (MSG), an established headache trigger, has become far more prevalent in canned, packaged and prepared foods over the past decade. The presence of MSG in food may be difficult to detect since the terms "natural flavor," "flavoring," or "hydrolyzed vegetable protein (HVP)," all may appear on food labels to refer to MSG, according to current FDA food labeling codes. HVP typically contains 10-30% MSG. Case studies are presented in which the elimination of all food sources of MSG resulted in decreased headache frequency. Information and food lists helpful in identifying dietary MSG and HVP are presented. When patients are put on an MSG-free trial diet, attention needs to be given to identification of the wide variety of foods containing MSG and HVP.
Headache 1991 Feb
PMID:MSG and hydrolyzed vegetable protein induced headache: review and case studies. 203 71

Monosodium glutamate (MSG), a common flavor enhancer in various canned food and stereotypically associated with food in Chinese restaurants, has been claimed and tested to have side effects including headache and dizziness. However, the mechanism behind MSG-induced headache was not clear. Using dissociated mouse neuronal culture and cell injury assays, we determined whether incubation of neurons with clinically relevant concentrations of MSG induces cell swelling or death, and whether any measure can be taken to prevent or reduce MSG effects. We demonstrated that (1) Treatment with MSG induces a dose-dependent swelling and death of mature neurons (12-14 days in culture) with little effect on young immature neurons (<1 week in culture). The threshold concentration of MSG for neuronal injury is 3 microM; (2) MSG only injures neurons with little effect on glial cells; (3) Boiling MSG does not affect its toxicity but the addition of Vitamin C provides significant protection against MSG toxicity; (4) Pretreatment of neurons with a low dose of MSG reduces subsequent injury by a large dose of MSG. Together, our studies suggest that the side effect of MSG may be mediated, at least in part, by its toxic effect on brain neurons. Pre-exposure to low doses of MSG or the use of Vitamin C may prevent or reduce the side effects of MSG.
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PMID:Deciphering the MSG controversy. 2005 76

Monosodium glutamate (MSG) is a widely used food additive. Although it is generally considered safe, some questions regarding the impact of its use on general health have arisen. Several reports correlate MSG consumption with a series of unwanted reactions, including headaches and mechanical sensitivity in pericranial muscles. Endogenous glutamate plays a significant role in nociceptive processing, this neurotransmitter being associated with hyperalgesia and central sensitization. One of the mechanisms underlying these phenomena is the stimulation of Ca2+/calmodulin sensitive nitric oxide synthase, and a subsequent increase in nitric oxide production. This molecule is a key player in nociceptive processing, with implications in acute and chronic pain states. Our purpose was to investigate the effect of this food additive on the nociceptive threshold when given orally to mice. Hot-plate and formalin tests were used to assess nociceptive behaviour. We also tried to determine if a correlation between chronic administration of MSG and variations in central nitric oxide (NO) concentration could be established. We found that a dose of 300 mg/kg MSG given for 21 days reduces the pain threshold and is associated with a significant increase in brain NO level. The implications of these findings on food additive-drug interaction, and on pain perception in healthy humans, as well as in those suffering from affections involving chronic pain, are still to be investigated.
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PMID:Chronic Monosodium Glutamate Administration Induced Hyperalgesia in Mice. 2926 17