There is a link between anxiety and hypersensitivity of the gastrointestinal area. Also, microbiota state in the gut, mediated through the immune system, is interacting with the brain.
Van Oudenhove et al. (2007, p. 455) found a significant association between gastric hypersensitivity and personality traits that may be related to increased anxiety.
It is known that alterations in the human diet also potentially dramatically alters the composition of the gut microbiota, which can contribute to the development of gastrointestinal disease.
Luna and Foster (2015) point to recent reviews that reveal that there is a role between microbiota in the gut and the signaling from the gut to the brain. This connection may happen through humoral, neural, and cellular pathways. In any case, the immune system is a mediator in the gut-brain communication as it is known to cognitive sciences since a long time already (p. 38). In the same article Luna and Foster (2015) explain that even for moderately or not stressed individuals, the intake of different Lactobacillus can cause the decrease of anxious or depressive moods (p. 39).
In that case, we can conclude that a further treatment plan consideration is the possibility to include a nutrition specialist respectively a diet that is consisting of probiotic bacteria as found in fermented milk. Diet-related changes may positively influence the microbiota state of the gut and hence anxiety- and depression-like behaviors can change as well. Healthy diet in this regards may be interrelated and go together with the likewise important psychosocial stress factors that are addressed with rest, exercise, and mindfulness to treat anxiety disorder in a holistic way. According to Luna and Foster (2015), stress is also influencing the gut microbiota and is therefore on this way impacting behavior (e.g., anxious or depressive behavior) (p. 36).
Luna, R. A., & Foster, J. A. (2015). Gut brain axis: diet microbiota interactions and implications for modulation of anxiety and depression. Current Opinion In Biotechnology, 32(Food Biotechnology * Plant Biotechnology), 35-41. doi:10.1016/j.copbio.2014.10.007
Van Oudenhove, L., Vandenberghe, J., Geeraerts, B., Vos, R., Persoons, P., Demyttenaere, K., & … Tack, J. (2007). Relationship between anxiety and gastric sensorimotor function in functional dyspepsia. Psychosomatic Medicine, 69(5), 455-463.