Carbonated beverages have hit the dysphagia world by storm. Much of the recent dysphagia research has focused on the sensory portion of the swallow and how sensory drives the swallowing process. Part of the sensory process is carbonated beverages. One of the common misconceptions at this time is that carbonated beverages act as a nectar thick liquid.
The Sensory System
Carbonation is a sensory option for dysphagia rehabilitation. It’s effective through a process called chemesthesis, where the “bubbly” or “fizzy” of the carbonated beverage acts as a Trigeminal irritant. The Trigeminal Nerve or Cranial Nerve V is one of the major swallowing nerves. The Trigeminal Nerve has bare nerve endings making it more susceptible to sensory or afferent input.
Rather than acting as a nectar thick liquid, the carbonated beverage actually increases the sensory stimulation for the swallow. Sensory input (afferent drive) drives the motoric output (efferent drive).
Research of Carbonated Beverages Shows:
No significant effect on oral transit time, pharyngeal transit time, initiation of pharyngeal swallow or pharyngeal retention. Carbonated beverages sis however decrease penetration/aspiraiton with 5 & 10 ml swallows. (Saravou & Walshe).
Carbonated thin liquid significantly decreased the incidence of spillover, delayed pharyngeal response and laryngeal penetration compared to non-carbonated thin liquids. (Newman et al).
Drinks containing chemical ingredients that activate sour and heat receptors alter swallowing physiology greater than water. (Krival & Bates).
It is likely that sour and carbonated beverages reflect a more organized activation of the submental muscles because of more effective afferent input to the Nucleus Tractus Solitarius. (Miura, et al).
One of the important issues to consider when looking at research involving carbonated beverages is that the researchers in these studies do not use Coke, Pepsi or Sprite. They use Ginger Brew, Club Soda or carbonated citrus.
One Size Does Not Fit All
It is vital, as with any other compensation or technique to view the effects of carbonated beverages. As with other strategies, you may not see the same effect in every patient and sometimes, the strategy you choose may make the swallow worse.
Krival K, Bates C. Effects of Club Soda and Ginger Brew on Linguapalatal Pressures in Healthy Swallowing. Dysphagia (2012). 27: 228-239.
Newman, et al. Carbonated Thin Liquid Significantly Decreases the Incidence of Spillover, Delayed Pharyngeal Response and Laryngeal Penetration Compared to Non-Carbonated Thin Liquids. Dysphagia 2001: 16: 146-150.
Saravou K, Walshe M. Effects of Carbonated Liquids on Oropharyngeal Swallowing Measures in People with Neurogenic Dysphagia. Dysphagia(2012) 27: 240-250.
Miura, Yutaka, et al. “Effects of taste solutions, carbonation, and cold stimulus on the power frequency content of swallowing submental surface electromyography.” Chemical senses 34.4 (2009): 325-331.