Proper Breathing play an Essential role to your overall Health. It doesn't matter if you are Vegan, Keto, Paleo, ect if you are not Breathing Properly you will never really be Healthy! Mouth Breathing causes many problems which include Neurological/Respiratory issues, Sleep apnea, Crooked teeth, Less Attractiveness, and exposes you to more harmful Viruses, Bacteria and other Pathogens.
"Eminent authorities have stated that one generation of correct breathers would regenerate the race, and disease would be so rare as to be looked upon as a curiosity. Whether looked at from the standpoint of the Oriental or Occidental, the connection between correct breathing and health is readily seen and explained.
The Occidental teachings show that the physical health depends very materially upon correct breathing. The Oriental teachers not only admit that their Occidental brothers are right, but say that in addition to the physical benefit derived from correct habits of breathing, Man’s mental power, happiness, self‑control, clear‑sightedness, morals, and even his spiritual growth may be increased by an understanding of the “Science of Breath.” Whole schools of Oriental Philosophy have been founded upon this science, and this knowledge when grasped by the Western races, and by them put to the practical use which is their strong point, will work wonders among them. The theory of the East, wedded to the practice of the West, will produce worthy offspring." ~Yogi Ramacharaka