MSG is the salt of glutamate, an amino acid found naturally in meat and vegetables, and in the body. Almost 2 kg of natural glutamate are found in muscles, brain, liver, and other organs and tissues. Glutamate is also found in mother’s milk at levels 10 times that of cow’s milk. Natural glutamate and that from MSG are treated in exactly the same way by the body.

While there may be ‘triggers’ for headaches, there is no scientific evidence that glutamate added as a seasoning is a trigger. A review of the literature on food-triggered headaches (Ann Behav Med, 1990; 12: 51-651) concludes that there is no evidence to support an association between MSG and headaches. - S. Scott, International Glutamate Information Service, London SW1