Food additives are used to enhance the flavor or to change the color of foods. Additives that seem to trigger migraine headaches include monosodium glutamate (MSG), sodium nitrite, yellow dye #5, and aspartame.
MSG. MSG is a flavor-enhancing additive that may stimulate brain cells and cause electrical discharges. Increases in electrical discharges have been linked to headaches. MSG is often used in Asian cooking and is usually contained in prepackaged and processed foods, such as stocks, broths, flavorings, seasonings, sauces, and gravies. It may also appear on the label as autolysed yeast extract, hydrolyzed vegetable protein, and natural flavoring.
Sodium Nitrite. Sodium nitrite is a preservative that can dilate blood vessels in your head, causing pain. It acts as a preservative, preventing botulism, a type of food poisoning. It is also used to make meat pinker as well as add flavor. Sodium nitrite is usually found in hot dogs, canned or packaged meats, cold cuts, sausages, and some cheeses.
Yellow Dye #5. Yellow dye #5, also called tartrazine dye, gives foods a yellow color. This yellow color is sometimes used to make other colors such as orange, white, turquoise, green, and maroon. Many colored foods contain yellow dye #5. Drugs can also be colored with yellow dye #5. It is not known why yellow dye #5 triggers headaches in some people.
Aspartame. Aspartame is a sweetener with very few calories. Some people are sensitive to it. The exact way it causes headaches, however, isn't known. You can find aspartame in many reduced-calorie or sugar-free foods, sodas, gum, or medications. Check labels if you are sensitive to aspartame.