Digestion plays a very key role in Ayurveda’s understanding of human health and illness. Though Ayurveda contends that all diseases originate first in the mind, on a physical level this invariably manifests as a breakdown in metabolic function. Because of this, it gives great importance to the process of digestion, whereas modern medicine places much less emphasis on the body’s metabolic processes as the source of either health or disease.
Ayurvedic science offers an elaborate and detailed description of the body’s metabolic functions and their relationship to organ and tissue formation. It confirms the importance of efficient food conversion to supply the nutrients which enable each dhatu to perform its job. It also recognizes that health requires the proper elimination of the natural by-products occurring from the digestive processes.
A rough analogy can be drawn to a car engine. When fuel combustion in the cylinders is inefficient, the compression lowers and the car responds sluggishly. In addition, carbon produced by incomplete combustion starts to form deposits on valves and other parts of the engine, further damaging the engine’s compression and interfering with the car’s performance. In a similar manner, if metabolic conversion of food is incomplete, it can produce sluggishness or low energy. The undigested food material also becomes the source for degenerative diseases.
The Doshas and Digestion
Previously we briefly explained that the dhatus are formed sequentially, one being a metabolic refinement of the previous one. Proper formation of the dhatus requires the complete and efficient breakdown of nutrients supplied to the metabolic staging ground of that dhatu from the previous stages. It is therefore vital for health that metabolism be strong in all seven stages.
What then is responsible for strong, efficient digestion? As was mentioned in the previous chapter, neither the dhatus nor the malas have the specific ability to accomplish these complex metabolic functions. Only vayu, agni and jala, acting as vata, pitta and kapha doshas in the body, possess the specific intelligence sufficient to conduct these processes. Ultimately, everything to do with metabolic function and its relationship to health and disease boils down to the coordinated actions of the three doshas.
The disease process starts when the doshas natural relationship becomes imbalanced or impaired. Doshic action and digestion are locked in a functional interdependence in which an impairment in one necessarily involves an impairment in the other. When one or more of the doshas becomes deficient or excessive in their functioning, indigestion results.
Each dosha displays a twice-daily cycle of predominance, reflecting the influence of its respective bhuta in the environment. Howevet, when a doshas dominance continues outside the normal time period, it becomes “aggravated.” An aggravated dosha no longer interacts in a balanced manner with the other two. It overwhelms them and inhibits their ability to perform their respective operations. Whether it’s kapha’s ability to liquefy and bind, pitta’s capacity to transform, or vata’s ability to separate and transport, their activity becomes weak or sluggish,. The precise coordination of all three of these functions is critical to healthy digestion.
The doshas perform many functions within the body, but in regards to the processes concerned with transforming foodstuffs into nutrients for the dhatus, pitta dosha has the most crucial role. The question then arises as to the relationship between agni, the vital force in the body and pitta dosha.
Relationship Between Agni and Pitta
A key concept in the Ayurvedic understanding of digestion is “digestive fire,” the process responsible for metabolic conversion within the body. Anything having to do with heat, light, conversion or transformation anywhere in the universe is under the control of the bhuta or element of agni. In the body, however, agni turns over some of its functions to pitta dosha. Before we proceed further with our discussion of digestion, it will be useful to clarify the roles that agni and pitta dosha have in the body.
Agni’s role in human physiology covers a multitude of functions. It produces vigor and vitality, the glow of the complexion, sight, thermogenesis and the structure of the dhatus. In fact, agni is responsible for life itself. In the context of the digestive processes that occur in the G-I tract, agni bhuta is called jathara agni.
Jathara agni manifests more specifically in the body as the five forms or sub-doshas of pitta. Each of these has a specific metabolic function and location in the body. The most important of these sub-doshas for our discussion here is pachak pitta, which is found in the lower stomach and small intestine, and is referred to by Ayurveda as the “digestive fire.” This function of pitta is what is responsible for our appetite and digestive ability.
Five Types of Pitta and their Locations
Pachak Pitta – Small Intestine
Ranjak Pitta – Liver
Alochak Pitta – Eyes
Sadhak Pitta – Brain
Bhrajak Pitta – Skin
The other four digestive activities of pitta which are closely related to pachak pittas activities are ranjak, which controls the liver function; alochak, found in the eye and is responsible for digesting visual images; bhrajak, located in the skin and is responsible for complexion; and finally sadhak pitta, which controls thought metabolism.
Just as agni bhuta manifests in the G-I tract in the form of jathara agni or pachak pitta, it also appears as the metabolic function responsible for creating and maintaining all seven dhatus. In this role, agni is known as the seven dhatu agnis.
Though jathara agni and the dhatu agnis have their respective pitta functions, it is important to understand the distinction between agni and pitta. As an element, agni has no distinguishable form in the body; it cannot be identified by material qualities. However, when it appears as pitta dosha, it is perceptible, because it becomes cloaked in the characteristics of all five elements. For instance, when jathara agni appears as pachak pitta, it exhibits properties that are characteristic of digestive enzymes and acid secretions, i.e., it has a slightly oily, liquid quality that moves or flows. It also has a distinctly sour odor and taste, and a yellow, green or reddish color.
Another important difference is that agni’s basic nature is to convert and consume, a process that never stops. When no food is available to convert, agni digests the oily and liquid substances of pitta and kapha doshas. When that is gone, it starts to consume the dhatus. This explains why fasting or starvation produces emaciation. In contrast, when there is no longer food to digest, pitta leaves the gastrointestinal tract and is eliminated as mala, the bile which gives the feces its brown color.
When both the digestive fire or pachak pitta are strong and in balance, the appetite is good without being excessive and digestion goes on almost unnoticed. Moderate eating satisfies us. We feel light and energized after eating and do not experience any strong food cravings. Food gets completely metabolized and the refined end-products of digestion move to the right tissues, in the right quantity to nourish the dhatus. Since proper metabolism is so crucial to health, it is important to first understand what causes digestion to malfunction and why Ayurveda links it to the formation of almost all disease processes.