We have already briefly looked at agni (Sanskrit for ´fire´ and cognate with the Latin ´ignis´) in a discussion of the concept of five elements. To recapitulate, agni as a principle represents heat and light, combustion, metabolism and transformation.
Fire has been revered in virtually all cultures for its provision of light, warmth, and its ability to transform raw materials into food. In some cultures, including the Vedic, fire is still considered sacred and fire rituals play an important role in worship and cultural and religious rites. Fire transforms the gross into the subtle, both physically and mentally. (The god of fire, dispeller of the night, ‘’the radiant one’’ of the Rig Veda, with fierce sun-like energy, who both purifies and ´´eats up´´ the dead, as well as carrying the sacrifices of humans to the gods, is also called Agni.)
The sun, without which we could not live, turns raw material, plants, into energy for humans through photosynthesis, and cooking transforms raw material into more digestible food. The digestive flame completes this process by breaking down food so that it can be separated, nutrition can be assimilated and waste products expelled. Agni is not only responsible for the breakdown of dense physical matter in the form of food, but for the digestion and assimilation of other information, sensory experiences and emotions. (Everything we ingest provides information of some kind and is either necessary or unnecessary, and beneficial or harmful, to our bodies and minds).
Agni works in our digestive tracts as stomach acid and digestive enzymes, in our brains as information is processed, in our eyes as light is perceived and transformed into images and in our skin where it determines temperature. In fact its presence throughout the cells of the body is responsible for all metabolic functions As such it is vital to significant transformations of the body – digestive function, cellular metabolism, mental perception, and overall health and well-being.
Psychologically, fire is the light of intelligence but is also anger, hatred, criticism and competitiveness. The guna of fire are hot, sharp and spreading. We use ´fiery´ or ´hot´ to describe the temperament of someone who is easily roused to passion or anger.
Ayurveda has described the underlying function of digestion and metabolism in our body as agni and Charaka stated that balanced agni is one of the most important factors in a person being healthy and leading a long life. Digestive fire, agni, is a function of pitta. Both aggravated and weakened pitta will mean disturbed agni whereas balanced pitta will mean balanced agni. (We should remember, however, that all dosha are involved in digestion. Vata controls appetite and hunger mechanisms and the transport of digestive enzymes, while kledak kapha is responsible for stomach mucous.)
Agni should be balanced for excellent digestion and good health, neither too low, nor overly high: just high enough to completely metabolise food without leaving any of it undigested or half-digested. Agni should transform food into nutritional rasa that can be absorbed by the body. If agni is too low, food is only half cooked, creating ama (literally the toxic result of undigested food particles) in the body, if agni is too high, food is burnt up too quickly and insufficient nutrition is absorbed.
“Due to the purification of the body, the capacity of digestion and metabolism is enhanced, normal health is restored, all sense organs start working with vigor, old age is prevented and diseases cured.” – Charaka Samhita Ch. 16 Sutra 17-19