Concept of metabolism of Agni
Ayurveda has described an important factor of digestion and metabolism in our body as Agni. Ingested food is to be digested, absorbed and assimilated, which is unavoidable for the maintenance of life, and is performed by Agni. In Ayurveda, the term ?Agni? is used in the sense of digestion of food and metabolic products.
Agni converts food in the form of energy, which is responsible for all the vital functions of our body. Therefore, Ayurveda considers that Agni is the cause of life, complexion, strength, health, nourishment, lusture, oja, teja (energy) and prana (life energy). (Cha. Chi. 15/3.)
About the importance of Agni, Acharya Charak has mentioned that after stoppage of the function of Agni, the individual dies, and when the Agni of an individual is stable, then that person would be absolutely healthy and would lead a long, happy, healthy life. But, if the Agni of a person is vitiated, the whole metabolism in his body would be disturbed, resulting in ill health and disease. Hence, Agni is said to be the base (mool) of life. (Cha.Chi.15/4.)
According to modern medicine, metabolic processes, division and multiplication are going on in all cells (dhatuparamanu) of our body from birth till death. The cell is the functional unit of the body. According to Charak, the constituent parts of the body, if further divided into the atoms, are sure to become innumerable, as such cells or atoms are exceedingly numerous, very minute and ultrasensory. In the conjunction and disjunction of cells, the activating factors are Vata and the nature of action (Cha. sha.7/17). In Shushrut, we can see how the ?Avayavaas? are formed from ?various dhatus? (Su.Sha.4/25-30). Thus, based on Charak and Shushrut, the above cells can be considered as ?dhatuparamanus.? For these constant processes in all cells, a biological energy is constantly essential, without which the survival of our body will be quite impossible. The same biological energy is provided by Agni in Ayurveda. This Agni-provided biological energy in the cells (dhatuparamanu) of our body is of two types: potential and kinetic.
Modern concept: -
As long as life in man, every organ , tissue, cells has to undergo process of constant change to meet the survival needs and ambitions in the world. This constant process of change either for yielding energy catabolism or synthesis of tissue anabolism an inherent factor is exists this can be considered as agni in Ayurveda.
Agni only bring out the changes of either qualities or quantities but never produce new substances. As per charaka quates Agni is the only facto whose presence is survival and absence is death. So agni is the form of energy and it is always a functional unit and not a structural unit. Hence as many thing it is not appropriate to call or label any particular substance or atom as agni, those are only the particles which delivers tha action of agni on cetain reactions with another substances or partivles which is obvious that the agni phenomena goes at all the levels of the body starting from GI tract (jadaragni) at elemental level (bhootagni) and cellular level (Dhtwagni) and is prevailing in the organism.
Jadara + Agni is jadaragni so jadaragni means agni which is located in the Jadara (Abdomen) amasya or annavaha srtothus. The agni is called Jadaragni. Functions of jadaragni include digestion of food absorption of nutrients separation of waste into stool and urine.
The functions of jadaragni are carried out by the enzymes and chemical substances and certain physical maneuvers like different types of intestinal movements that is the physio-chemical process starting from the mouth and end at the GI tract. It may not be proper to attribute the functions of Jadaragni to a particular enzymes or substance in GIT, hence all the process of digestion and absorption can be considered as the moieties of Jadargni. The main location of jadaragni is in the pitta dhara kala in grahani located between amasaya and pakwasaya .
Types of Agnis
Agni is innumerable because of its presence in each and every minute aspect of the body. But, classification of Agnis varies in various classical Ayurvedic texts, as shown below
? Charaka has mentioned about 13 Agnis. Jatharagni ? 1, Bhutagni ? 5, Dhatvagni ? 7 (Ch.Chi.15/38).
? According to Acharya Sushruta, five types of Agnis are illustrated, viz. Pachakagni, Ranjakagni, Alochakagni, Sadhakagni and Bhrajakagni. However, there is an indirect reference of five Bhutagnisunderlying in the brief description made to the transformation of food stuff. (Sh.Su.21/10.)
? Vagbhata has described different types Agni, viz. ? Bhutagnis ? 5,? Dhatvagnis ? 7, ?Dhoshagni ? 3 and? Malagni ? 3.
? Sharangadhara has recognized five pittas only (Pachak, Bhrajak, Ranjak, Alochaka and Sadhak) (Sha.Sa.Pu.Kh.-5/32).
? Bhavamishra has followed Acharya Charaka and Vagbhata (Bh.Pu.Kh.-3/169,180). Agni has been divided into 13 types according to the function and site of action. These are:
1. Jatharagni ? one Agni present in the stomach and duodenum.
2. Bhutagni ? five Agni from five basic elements.
3. Dhatwagni ? seven Agni present, one in each of the seven dhatus.
Accordingly, they are classified into three groups, namely Jatharagni, Bhutagni and Dhatvagni.
Jatharagni
Jatharagni is the Agni or literally means fire, present in the Jathara (possibly between stomach and duodenum). According to Ashtanga Hridaya, Jatharagni, the seat is grahani (duodenum), so called because it withholds the food for a certain time inside the Amasaya (stomach) to facilitate digestion. In the opinion of Dhanvantari, it is the Kala(Group of tissues/) known as ?Pittadhara,? situated at the entrance of the Pakvashaya (intestine) and acting as a bolt to the door of the pathway/channel of food. It is responsible for the duration of life, health, valour, ojas (essence of the dhatus), strength of all the bhutagni and dhatvagni. The strength of the grahani is from Agni itself, and the strength of Agni is from grahani. When the Agni undergoes vitiation, grahani also gets vitiated and produces diseases. (As.Hr.Sha.3/50-54).
In the light of recent consideration of mesentry as an organ, we are not sure what else is there yet to be understood.
Jatharagni is considered to be the most important because each and every nutrient that one ingests first comes to the Jathara and Jatharagni digests the food materials that consist of the five basic elements and transforms it for utilization by the respective Dhatus paramanus(tissues). Jatharagni is also responsible for separation of the food material into the essence portion (Sara) and the waste products (kitta) in our body (As.Hr.Su-12/8).
Jatharagni is directly related to Dhatvagni or ?fire? in the cells and their metabolic processes, with ultimate tissue metabolism or Dhatu-Paka process. All the Dhatvagni depend on the normal, healthy state ofJatharagni. If the Jatharagni is hyperactive (Tikshna) or hypoactive (Manda), it will cause an excessive or retarded action of the Dhatvagni. This disturbed action ultimately leads to various disorders. Jatharagni is the main important Agni that controls the function of all other 12 Agnis. All the Agnis are totally dependent on the status of Jatharagni (Cha. Chi. 15/39-40).
Jatharagni is also classified into four categories according to its performance of digestion in the human being (Cha. Chi. 15/51), namely Vishamagni, Tikshanagni, Mandagni and Samagni. According to Hareet Samhita, Samagni depends on whether the Doshas (Vata, Pitta, Kapha) are in normal stage. When the Pitta is higher than normal, the condition is known as Tikshnagni. When Vata and Kaphaare higher than normal, the condition is known as Mandgni.
? a) Samagni: The Samagni digests and assimilates food properly at the proper time. This thus increases the quality of the Dhatus (supportive tissues of the body). Persons having Samagni are always hale and healthy.
? b) Vishamagni: This type of Agni changes between digesting food quickly and slowly. When this Agni is affected by the Vata Dosha, it creates different types of udargata roga.
? c) Tikshnagni: Tikshnagni means very quick/very sharp/very fast. Tikshnagni is a state of very quick digestion of food, regardless of the type of food. Acharya Shushrut states that when the power of digestion is increased from normal to above normal, food digests very quickly and produces hunger or the desire for food. When food is digested, the throat, the mouth cavity and the lips become dry with a burning sensation. This condition is known as ?Bhasmak Roga? according to Ayurveda.
? d) Mandagni: ?Mand? means slow. The meaning of the Mandagni is slow digestive power or digestive capacity. Those who are having Mandagni eat very little and are unable to digest the smallest amount of food. Dhanvantri says that Agni digests the least amount of food in the greatest amount of time.
Bhutagni
Bhutagni is the one that is present in a basic element (Bhutas). There are five Agnis in each of the five basic elements, namely ? Parthiva (earth), Apya (water), Tejas (Agni), Vayavya (vayu) and Nabhasa(akash).
Each and every cell in our body is composed of the five mahabhutas or five basic elements. Naturally, each cell (dhatu paramanu) consists of these five Bhutagni also. All the nutrients in this world that we eat also consist of the same five basic elements with their respective Agni or bioenergies. Thus, they are completely similar with respect to the five basic elements with their Bhutagni in our body cells as well in all the outside nutrient, that we ingest for the nutrition of our body. Acharya Charak has mentioned that the five Bhutagnidigest their own part of the element present in the food materials. After the digestion of food by the Bhutagni, digested materials containing the elements and qualities similar to each bhutas nourish their own specific bhautika elements of the body (Cha. Chi. 15/13, 14). These Bhutagnis act after the Jatharagni present in the stomach and duodenum, acting on the food and causing their disintegration. In the modern physiological perspective, the action of Jatharagni can be equated with the digestion in the stomach and duodenum, and the action of the Bhutagni can be equated with the conversion of digested materials in the liver.
Dhatvagni
All the seven Dhatus (seven element tissues of the body) contain their own Agni to metabolize the nutrient materials supplied to them through their own Srotas.
1. Rasagni present in the Rasa Dhatu.
2. Raktagni present in the Rakta Dhatu.
3. Mamsagni present in the Mamsa Dhatu.
4. Medagni present in the Meda Dhatu.
5. Asthyagni present in the Asthi Dhatu.
6. Majjagni present in the Majja Dhatu.
7. Shukragni present in the Shukra Dhatu.
Each Dhatvagni or the bioenergy present in each Dhatu synthesizes and transforms the essential Rasa Dhaturequired for that particular Dhatu or cell from the basic nutrients present in the AnnaRasa or essence of the diet that we consume. Each Dhatvagni has got a speciality to synthesize and transform the constituents suitable to its particular Dhatu. This action is a sort of selective action. Acharya Charaka has mentioned the fact that that the seven dhatus that are a support of the body contain their own Agni, and by their own Agnithey digest and transform the materials supplied to them to make the substances alike to them for assimilation and nourishment (Cha. Su. 28/15).
Source: Physiological aspects of Agni
Akash Kumar Agrawal, C. R. Yadav,1 and M. S. Meena1