Saliva is a basic fluid found in organisms ranging from insects to humans, and it contains several molecules needed for normal physiological functioning. Environmental factors activate salivation, so saliva is a critical bridge in translating external stimuli into biological responses. Saliva is normally considered a rich source of digestive enzymes, and studies show that it contains more than 1,000 proteins and other biologically active molecules that influence the body’s functions. For instance, people with depression produce less saliva, and “dry mouth” occurs alongside several chronic psychosomatic conditions. Clearly, normal salivary flow is important to good health, but it can also be affected by treatments such as radiation therapy for head and neck cancers. Reduced salivary flow results in dramatically reduced quality of life, so strategies for activating salivation are needed to manage dry-mouth conditions and the symptoms that go with them.
Salivation is induced in the body by the parasympathetic (rest-and-digest) arm of the autonomic nervous system. Although there are several pharmacological methods for inducing salivation—and even artificial saliva—my own work considers the pathway of breathing regulation. In our 2016 research study, when human subjects engaged in breathing regulation (pranayama, or yogic breathing) with or without vocalization, they were able to stimulate saliva production. My personal experience performing a breathing exercise from an ancient yogic text, the Thirumanthiram, prompted this work.
Practicing a breath-holding exercise from this literature produced saliva rich in biologically important molecules. Our first discovery was that when study participants performed 20 minutes of breathing exercises, they produced more salivary nerve growth factor (NGF). A member of the class of molecules called neurotrophins, NGF is thought to be important for treating Alzheimer’s disease. The ways in which salivary molecules are transported to the central nervous system and elsewhere make it possible for these breathing practices to stimulate NGF. We also discovered that pranayama practice stimulates proteins known as tumor suppressors, as well as salivary molecules critical for our immune responses (immunoglobulins). Levels of proinflammatory proteins (cytokines such as interleukin-1 beta and IL-8) can also be reduced by the practice of pranayama.
Our studies represent the first evidence that breathing regulation can alter salivary constituents, paving the way for better physiological and emotional well-being. Further studies are underway in various disease conditions in which pranayama could be a useful aid to symptom management.Sundar Balasubramanian, PhD, C-IAYT, is a researcher at the Medical University of South Carolina and the founder/director of PranaScience Institute. He was a speaker at TEDx Charleston 2015 and is the author of PranaScience: Decoding Yoga Breathing.