Vaidya M.Prasad, MD (Ay.)
It is a popular belief that good quality food is the essential prerequisite for maintaining good health. No doubt, it is true. But it is not the only truth. The capacity of an individual to handle a food-stuff is equally important. This capacity is known as his/her digestive power. Ayurveda calls this power as Agni. Agni is a Sanskrit word which means fire. As long as the Agni is working properly, everything else is secondary. We may see more about the functioning of this unique faculty.
The food we eat is converted to the body by a series of changes. This is an essential mechanism of survival of any living system. Body needs lots of energy for the repair of its daily damages. It needs regular nourishment of the depriving elements. Newer tissues are replacing the old and aged ones. That is why we need food. So what is a food? Food is a substance which can be utilised by the body-systems to make its basic tissues so as to ensure its survival. (Of course, this definition excludes the socio-cultural aspects of food). But such a substance can deliver its duty only if it is acceptable to the biological system. Consider the example of poisons. They may be proteins in their content. But these proteins are not acceptable to the body and if consumed they kill the system. This is because, Agni cannot process a poison. The capacity if the Agni to process food is miraculous. It breaks the complex structures into simpler forms. Make a pool of basic elements. And facilitate re-organization of such basic elements to form the body-tissues. In this process, it adapts in a thousand ways to make sure that every stage of this complex transformation is executed properly. It tries to nullify the toxic elements of the food stuffs. If failed in this effort, it makes sure that such things do not get entry into the system. Any object, unacceptable to Agni, is rejected by the system. So in short, agni processes the food, detoxifies it, digests it, re-organizes it, assimilates it, and make sure that re-building of tissues take place unhindered. In short, the very survival of an individual is based completely on the capacity of his/her Agni to perform. That is how Agni became a representation of divinity if not God himself.
Ayurveda gives the topmost priority to the capacity of Agni to perform; in healing as well as in health. Chikitsa (healing) is in effect nothing but Agnichikitsa (maintenance of Agni). And the ultimate aim of any chikitsa is to preserve and sustain Agni. It may be interesting to note that all the seven types of Samanachikitsa (treatment by pacifying the doshas) in ayurveda are based on the manipulation of Agni.
published in academia.edu