Foods that are riper or have been longer standing tend to have higher tyramine content than fresh or freshly-prepared foods. Thus a piece of fruit that is fresh and firm may be well tolerated, but a ripe or especially over-ripe piece of the same food may provoke a serious reaction. Furthermore, bacterial action on protein sources such as meat and soy products can cause an increase in the food's tyramine levels. In summary, the caution regarding foods high in tyramine is that firm and fresh is more likely to be safe than over-ripe or over-exposed to potential bacterial overgrowth.
High tyramine-containing foods (items in the list below that are bolded contain high to very high amounts of tyramine):
Analysis of pizzas from large chain commercial outlets found no significant tyramine levels in any of the pizzas tested, including those with double pepperoni and double cheese. Marked variability was found with soy products, including significant amounts of tyramine found in tofu when stored for a week, and high tyramine content of some soy sauces. The authors of this study concluded that pizzas from large chain commercial outlets are safe for consumption with MAO inhibitors. However, they recommended caution when ordering from smaller outlets or with gourmet pizzas that may use aged cheeses. All soybean products should be avoided.
Tyramine-containing foods are responsible for migraines in 15% of sufferers. If you have observed a sensitivity to such foods, you should try a tyramine-free diet for a short time. If headaches resolve, reintroduce foods high in tyramine. If headaches recur, you may be able to control your headaches by avoiding these foods; if not, you may be allergic to other foods.
Only those using hydrazine sulfate are required to avoid tyramine-containing foods.