In my last blog, we began discussing digestion from the view of Ᾱyurveda. We spoke about how the 5 elements each had their own type of energy, and discussed mainly the fire element, Agni.
Just as in western nutrition, Ᾱyurveda recognizes stages to the digestive process. Each of these stages relates to one of the 6 tastes.
To review the 6 tastes, please read my previous blog: Thinking About Taste in a New Way.
Digestion requires 6 or more hours to complete. Each of the following 6 stages relates to one hour. After the initial taste on the tongue, the tastes also travel in the Ᾱhāra Rasa (the nutritive juice that is the end product of digested food). The Ᾱhāra Rasa takes about 12 hours to form and is the nutritive beginning to all tissue formation.
Stage 1: “Sweet stage” or Madhura avasthā Pāka.
(avasthā means “stage” and “Pāka” means digestion) This stage begins in the mouth with saliva. Saliva is stimulated by Prāna Vāyu (the direction that prāna moves in the head, downward and inward).
Oral temperature, lubrication, and the beginning of starch digestion are regulated by saliva. The act of chewing, along with water, helps saliva break down the food into small particles in the mouth. Prāna moves the food down the esophagus into the stomach and Samāna Vāyu (the direction of prāna in the digestive system), initiates the churning in the stomach. It is the water and earth elements that stretch the stomach to give a sense of fullness and satisfaction.
Absorption of simple sugars promotes energy and contentment. The taste perception is by way of Bodhaka Kapha (a subtype of Kapha) or saliva, Prāna Vāyu (inward and downward flow of prāna), and Sādhaka Pitta (the pitta subtype responsible for memory, intelligence, enthusiasm, and in this case, mental digestion.) Asthāyi Rasa Dhātu (the beginning of the plasma level of tissues or the immature, unformed tissue) is yielded from the sweet taste.
Stage 2: “Sour stage” or Amla avasthā Pāka.
It takes place in the stomach. The stomach secretes hydrochloric acid (Pāchaka Pitta, a subtype of pitta dosha) which makes the food acidic. The stomach lining is protected by Kledaka Kapha (a subtype of kapha dosha, a mucus that lines the stomach and protects it from the strong stomach acids).
The fire element promotes digestive enzymes and lightens up the heavy feeling from the stomach due to its earth element. Protein and fat digestion begins in the stomach. The Sour taste is yielded into Asthāyi Rakta Dhātu (the beginning of the red blood cell tissue layer, or the unstable, immature red blood cell layer).
Stage 3: “Salty stage” or Lavana avasthā Pāka.
Food leaves the stomach through the pyloric valve and enters the duodenum, the first section of the small intestine.
With the help of Samāna Vāyu (the direction of prāna through the digestive system), Pāchaka Pitta (a subtype of pitta dosha or digestive juices), and Rañjaka Pitta (also a subtype of pitta dosha or otherwise known as bile), digestion occurs. The food that has entered from the stomach is acidic, but once it is exposed to the bile and the pancreatic juices (which are alkaline) it becomes salty.
Acid and alkaline are equal to salt and water. The salty taste helps with the further digestion of fats and proteins with its buffering action. This stage of digestion yields salty taste into the Rasa Dhātu (the lymph tissue layer) which then nourishes the beginnings of muscle and fat tissue (Asthāyi Māmsa Dhātu and Asthāyi Meda Dhātu).
Stage 4: “Pungent stage” or Katu avasthā Pāka.
This occurs in the jejunum, the second part of the small intestine. In this stage, air and fire are predominant. The fire is used for the digestion of food. Pungent enzymes, found in the upper part of the jejunum, have a lot of fire element thus their hot qualities. These hot qualities also increase heat and circulation.
If the heat is increased too much, one may experience hemorrhoids, skin rashes and bleeding disorders. Air and its ability to move, is useful in the initial absorption of the nutrients. (Most absorption occurs in the ileum and colon. Gases and intestinal peristalsis, via Samāna Vāyu are also products of air.) This stage yields Rasa Dhātu (the lymph tissue layer) and nourishes Asthāyi asthi dhātu, (or the immature, unstable, beginning bone tissue layer).
Stage 5: “Bitter stage” or Tikta avasthā Pāka
This occurs when the food enters the ileum or the third part of the small intestine, where further digestion takes place. Air and ether, which contribute to the bitter taste (along with bile still being present), move the food through the villi of the ileum wall and allows for absorption.
Samāna Vāyu continues to stimulate peristalsis. Because of the ether and air quality of lightness, false hunger may be experienced, but this is not a good time to eat. The astringent stage is next, and one should not eat again until it has been completed for about an hour. The bitter taste is manifested into Rasa Dhātu (lymph) and nourishes the Asthāyi Majjā Dhātu or the immature, unstable, beginning layer of nerve tissue.
Stage 6: “Astringent stage” or Kashāya avasthā Pāka
This is the final stage. The cecum, which is the first portion of the large intestine, receives what is left of the foodstuffs.
Earth and air are the elements of astringent. The air element allows for absorption, while earth is heavy and gives bulk to the stools. The astringent taste is necessary for the absorption of certain vitamins, water and minerals which takes place in the ascending colon and the first half of the transverse colon.
In the second half of the transverse colon and the descending colon, the fecal matter develops as the liquid is absorbed through the colon and eliminated via the kidneys and the bladder as urine. Mass peristalsis is stimulated in the astringent stage and the air element in the form of Apāna Vāyu (downward moving prāna), causes the urge to defecate. Rasa dhātu (lymph) is yielded from the astringent taste and Asthāyi Shukra or Ᾱrtava Dhātu (the immature layer of the male and female reproductive tissues) are nourished by it.
So as western nutrition describes somewhat the same process of digestion, eastern nutrition breaks it down even further and includes the subtle energies (Prāna and the Doshas) at work and what layers of tissues that are being initially affected.
Look to a future blog to see what happens next. It just keeps getting better!