Ayurveda explains the digestion strength as Agni. Agni is a Sanskrit word meaning fire. All the factors involved with digestion – enzymes, Hydrochloric acid, etc are collectively termed as Agni. Let us forget about the modern process of digestion and try to learn about it in purely Ayurvedic perspective. So, for the time being please avoid thinking about enzymes, metabolism etc.
The way the ancient seers were looking at human physiology is quite different from the modern perspective. One of the ways they were using to learn and understand human body was comparison.
They learnt in no time that – as wind, light (and heat) and water control the nature, similarly Vata, Pitta and Kapha control the human body. They called these three as Tridosha. Good wind, good light, and good water can maintain the health of nature. But if wind goes awry, like, a storm, if Sun goes awry, like a sudden increase of temperature or a volcanic eruption and if the water goes awry, like a cyclone or a drought, the nature’s health gets disturbed. Similarly, when Vata, Pitta and Kapha are in normal state, it leads to good health and if they are increased / decreased, it leads to disease. (learn more about Tridosha in my ebook – Tridosha – Basic Principle of Ayurveda)
Like Tridosha control all parts of the body, they also control the Agni – digestive power.
Ayurvedic understanding of digestion – Video
Agni and Pitta – Wherever there is processing with fuel, like running of a motor engine, there is an element of fire involved. Hence, even in the process of food digestion, where food is used as fuel by the body to burn and generate energy, there is predominant involvement of fire.
So, Pitta is the main component of Agni. (In fact, Agni itself means fire.).
Agni and Vata – But as we know, fire alone can not burn a mass. It needs some amount of air as well. Proper quantity of oxygen rich air will keep the fire alive. Wind is correlated with Vata in Ayurveda. Hence, the process of digestion also involves Vata. For your digestion process to run smoothly, your Vata should also be in a healthy state.
Agni and Kapha – When there is a big mass, to burn it, only fire and wind might not be sufficient. You need some lubricating liquid, that would soften and break down the mass into small particles. Liquid / water is correlated with Kapha. Hence, you need a little amount of Kapha also, in the digestion process.
So, Agni is contributed by
Pitta – which acts as the main burning power, which burns the food and divides it into useful part (Rasa) and waste part (Mala – faeces)
Vata – which helps in maintaining proper Pitta. It also helps in the division of useful part and waste part. Vata is responsible for movement of the food taken in, in normal downward direction, from oral cavity to anal canal. It is also responsible for division and further assorting of useful part of food and waste part.
Kapha – which helps in lubricating the food. It helps to break down the food particles into small pieces.
What actually happens during digestion?
At the level of stomach and intestine,
The food received into stomach, gets broken down into minute particles, which further get divided into
Essence part – Sara Bhaga – which goes on to nourish all the body tissues (explained below) and
Waste part – Kitta Bhaga – which goes on to form all the waste products of the body – like feces, urine, sweat etc.
How body tissues get nourishment?
There are seven types of body tissues as per Ayurveda, called Dhatu. They are –
Rasa Dhatu – Essence part of food, also compared with plasma and lymph.
Rakta Dhatu – blood tissue
Mamsa Dhatu – muscle tissue
Asthi Dhatu – bone tissue
Majja Dhatu -Bone marrow tissue
Shukra – male and female reproductive systems. Read more about Dhatu – body tissues
The essence part of food nourishes the Rasa Dhatu. From there on, each Dhatu nourishes the next Dhatu successively.
Each Dhatu has its own Dhatu Agni.
Dhatu Agni means, digestive fire at tissue level.
This Dhatu Agni converts the nourishment that it receives, into respective tissue.
Rasa Dhatu has Rasa Dhatu Agni – The digested food is processed by Rasa Dhatu Agni, to nourish Rasa Dhatu. Then the remnant food part flows to Rakta Dhatu (blood tissue).
Rakta Dhatu (blood tissue) has Rakta Dhatu Agni – The remnant digested food that flows into Rakta Dhatu, gets digested and absorbed by the Rakta Dhatu Agni to nourish blood tissue (Rakta). The remnant part of digested food flows into Mamsa Dhatu (muscle).
Mamsa Dhatu (muscle tissue) has Mamsa Dhatu Agni – The remnant digested food that flows into Mamsa Dhatu, gets digested and absorbed by Mamsa Dhatu Agni to nourish muscle tissue (Mamsa). The remaining digested food flows into Asthi Dhatu (bone).
Asthi Dhatu – Bone tissue has Asthi Dhatu Agni – The remnant digested food that flows into Asthi Dhatu, gets digested and absorbed by Asthi Dhatu Agni to nourish bone tissue (Asthi). The remaining digested food flows into Majja Dhatu (marrow).
Majja Dhatu – Bone marrow has Majja Dhatu Agni. The remnant digested food that flows into Majja Dhatu, gets digested and absorbed by Majja Dhatu Agni, to nourish bone marrow. (Majja). The remaining digested food flows into Shukra Dhatu (reproductive system).
Shukra Dhatu – reproductive system- has Shukra Dhatu Agni. The remnant digested food that flows into Shukra Dhatu, gets digested and absorbed by Shukra Dhatu agni, to nourish reproductive system (Shukra).
Thus, from Rasa to Shukra, all the seven dhatus get nourished, respectively by one another, with the help of respective Dhatu Agni (digestive fire component of respective tissue).
How waste products get nourished?
Food, after digestion takes two forms viz,
Prasada – the essence part, that is formed in the first stage. This is also called as ‘Rasa’
Kitta – the waste part. The waste part further nourishes
Sweda – sweat,
Mootra – urine
Pureesha – feces
Tridosha – Vata, Pitta and Kapha
Excreta of the ear, eye, nose, mouth, hair follicles, as well as genitals organs and also
Kesha – hair of the head,
Shmashru – beard,
Loma – small hair of the body,
Nakha – nails etc.
Related explanation from Charaka Samhita Chikitsa Stan 15th chapter:
Functions of Agni – Digestive fire
Dehagni or Jatharagni (power of digestion and metabolism) is the reason for
Ayu – life,
Varna – color, complexion
Bala – strength and immunity
Swasthya – good health
Utsaha – energy, enthusiasm
Upachaya – bulk, shape, plumpness of body
Ojas – immunity, disease resisting power (read more about Ojas)
Tejas – aura, complexion, radiance
Maintenance of other varieties of Agni and
Prana – Vital breath.
Extinction of Agni leads to death. Its proper maintenance helps a person to live longer and its impairment gives rise to diseases. Therefore Jataragni is considered to be the root or the most important sustaining factor (mula) of living beings.
Importance of Agni – digestion strength
Food provides nourishment to body and tissues and it is the reason for Ojas (vital essence, immunity), strength and complexion. But in effect, it is the agni (digestive strength) that plays a vital role in this connection because tissue elements like, rasa, etc., cannot even originate from undigested food particles, if Agni is not present.
Process of digestion
Prana Vata, draws the ingested food into the koshta – alimentary tract. In stomach, the food gets softened by the unctuous (oily)substance after which it gets split into small particles by the liquid.
The Agni (enzymes) located in the udara (stomach), gets stimulated by Samana vata. This Agni stimulated by vata, digests the food that is taken in required quantity and in right time for the promotion of longevity.
Consider a cooking pot containing rice and water, placed on fire. As the fire, placed below the cooking pot helps in the cooking of food, similarly, Agni (enzyme) helps in the digestion of food located in the Amashaya – stomach. This leads to the production of Rasa – chyle – nutrition rich resultant of digestion and Mala (waste products).
Avastha-paka – three stages of digestion process
1. Madhura Avastha Paka
As soon as the food consisting of 6 rasa (tastes) is taken, it goes to stomach and sweetness (madhura-bhava) is manifested during the 1st stage of digestion. It results in the stimulation of kapha which is thin and frothy in nature.
2. Amla Avastha Paka
During the second stage of digestion, the food remains in semi digested form (vidagdha) which results in sourness. While moving downwards from the amashaya (stomach), this (semi digested and sour stuff) stimulates the production of a transparent liquid called pitta (bile). Pitta itself is sour in taste.
3. Katu Avastha Paka
When this food product reaches pakvashaya (large intestine), it gets further digested (cooked) and dehydrated by the agni (enzymes), and it takes a bolus-form resulting in pungent taste. This stimulates Vata Dosha.
Satiation of sense organs by food
Intake of delicious and wholesome food that has pleasant appearance, smell, color, touch and sound nourishes and satiates the sense organs – nose, eyes, skin, tongue and ears.
Bhutagni paka – digestion by elemental fires
There are five types of Agni (digestive factors) based on 5 basic elements.
Parthivagni – responsible for digestion of solid food matters
Apyagni – responsible for digestion of liquid foods
Tejasagni- responsible for digestion of foods with fire element
Vayuvagni – responsible for digestion of air element and
Akashagni – responsible for digestion of food with ether element
They digest the respective elements and nourish the respective elements in the body. For example, Parthivagni digests solid foods and nourishes the solid body elements.
Dhatvagni- paka – absorption of digested foods at tissue level
Thereafter, the digested food is subjected to Dhatu Paka. Dhatu means 7 types of tissues (Rasa, Rakta, Mamsa, Meda, Asthi, Majja and Shukra). Each of these Dhatu have their own Agni – digestion power. With this again, the digested food gets divided into
Sara bhaga – essence part. This nourishes the respective Dhatu.
Kitta bhaga – waste product – this forms the waste product (Mala) of the respective Dhatu.
Process of metabolic transformation
The nutrient fraction of Rasa dhatu provides nourishment to Rakta (blood).
The nutrient part of Rakta (blood) nourishes mamsa (muscle tissue),
that of mamsa to medas (fat),
that of medas to asthi (bone),
that of asthi to majja (bone marrow), and
the nutrient fraction of majja nourishes Shukra (semen). The foetus (garbha) is the product of nutrient of sukra or semen (sperm).
Nourishment of upadhatus
Nourishment of upadhatus (subsidiary / secondary tissue elements)
Breast milk (Stanya)and menstrual blood (Arthava) are formed out of Rasa
Kandara (tendons) and vessels (Sira) are formed out of Rakta,
Vasa (muscle fat) and 6 layers of skin are formed out of Mamsa and
Snayus (sinews) are formed out of medo-dhatu.
The following are the malas (waste products) of anna (food) and dhatus (tissue elements):
Anna/ dhatu Mala (waste product)
1. Anna (food) yields stool and urine as waste products
2. Rasa yields Kapha (phlegm) as waste products
3. Rakta (blood) gives out pitta
4. Mamsa (muscle tissue) kha-mala (waste products excreted from the cavities like ears, eyes, nose, mouth and genital organs)
5. Medas (fat tissue) – sweat
6. Asthi (bone) kesa (big hair) and loma ( small hair)
7. Majja (bone-marrow) the unctuous substance present in the eyes, stool and skin
Thus, Prasada (nutrient fraction) and Kitta (waste product) these 2 categories of products arise out of the paka (metabolic transformation) of the dhatus (tissue elements). Therefore, the process of successive transformation of the dhatus is mutually inter- woven.
Time taken for metabolic transformation
According to some scholars, the transformation of dhatus from rasa to Shukra is effected in 6 days and nights. This process of transformation of the tissue elements requiring nourishment is a continuous one, like a moving wheel.
Jataragni, Dhatu agni difference
What is the difference between Agni, Jatharagni, Dhatu Agni? I have read about Kloma agni, pilu and pithara agni, dosha agni, mala agni etc as well?
Agni means the force for digestion and metabolism. Wherever food is converted into energy, there is Agni.
Jatharagni – one that resides in stomach and intestine, that digests food.
Dhatu agni – once the digested food enters circulation, it is taken up by muscle tissue, blood tissue, fat tissue etc.. these nourishments (metabolism) is handled by respective agnis at the level of body tissues.
Kloma agni, Pilu agni, Pithara agni etc – are recently coined terms. I have not found classical references for these yet.
Dosha agni – I have not heard about it.
Mala agni – Mala means waste product.
After the food is digested, the waste parts are converted into feces, urine and sweat. The factor responsible for these conversions is explained as Mala Agni.