Yes, anxiety can cause belching. Anxiety is associated with multiple gastrointestinal symptoms, including belching (Mussell et al., 2008). Anxiety and stressors affect your body. In turn, your body reacts by triggering the fight or flight response, where the sympathetic nervous system is activated by the amygdala and there is subsequent release of adrenaline into the bloodstream. In this adrenaline response, your body becomes faster and stronger to fight or flee from any danger in the environment.
The fight or flight response shifts all of your body's energy and resources into the essential systems needed for survival, such as the skeletal muscles and the cardiovascular system, and away from non-essential systems for survival, such as the gastrointestinal system and the reproductive system.
With the gastrointestinal system getting less blood flow and less resources, gastrointestinal symptoms arise, including butterflies in the stomach (fluttery feeling), lump in the throat, belching, bloating, abdominal pain, and nausea/vomiting.
Reference:
Gastrointestinal symptoms in primary care: prevalence and association with depression and anxiety. Mussell M, Kroenke K, Spitzer RL, Williams JB, Herzog W, Löwe B. J Psychosom Res. 2008 Jun;64(6):605-12.
