It is not surprising that transcutaneous auricular vagal nerve stimulation would affect the GI system since it is innervated by the vagus. But this study makes the connection in an elegant way. But pointing out that the end organ, the stomach, is affected by TAVNS, you see the actual, real life results of this intervention. Perhaps TAVNS can be helpful for reduction diets since it retards gastric emptying. I don’t have access to the entire paper, so I don’t know the exact protocol.
Non-invasive stimulation of vagal afferents reduces gastric frequency.
Metabolic feedback between the gut and the brain relayed via the vagus nerve contributes to energy homeostasis. We investigated in healthy adults whether non-invasive stimulation of vagal afferents impacts energy homeostasis via efferent effects on metabolism or digestion. In a randomized crossover design, we applied transcutaneous auricular vagus nerve stimulation (taVNS) while recording efferent metabolic effects using simultaneous electrogastrography (EGG) and indirect calorimetry. We found that taVNS reduced gastric myoelectric frequency (p = .008), but did not alter resting energy expenditure. We conclude that stimulating vagal afferents induces gastric slowing via vagal efferents without acutely affecting net energy expenditure at rest. Collectively, this highlights the potential of taVNS to modulate digestion by activating the dorsal vagal complex. Thus, taVNS-induced changes in gastric frequency are an important peripheral marker of brain stimulation effects.