Have you ever consumed a can of kombucha, some sauerkraut and soy sauce in a meal and felt on edge afterwards or has your heart rate increased? Why can this happen? Fermented foods contain the free (unattached) protein glutamate. The unattached nature of glutamate allows it to be absorbed almost immediately. A glutamate-containing meal or consuming many glutamate-containing foods throughout a day can cause a large spike in glutamate in the blood. Who is most affected by this?