In my thinking, Agni is the action of acids like HCl, NaCl and KCl plus the enzymes that break down the macromolecules into single, simple units. This is in the context of ‘agnipravarthana (action of fire) ‘ in gastrointestinal tract. In the intracellular context Agni can be the enzymes that break down the molecule itself into smaller and smaller molecules. This breaking down can be for transforming one molecule into another form for physiological purposes or for storage purpose or for generating energy.
Digestive related Agni:
Agni is pitha .So it is protons or positively charged ions like H+, Ca+ ,Na+ ,K+ etc. In the bucal cavity itself this agni is present in the form of enzymes.
In the stomach there are acids like HCl, NaCl,and KCl which are present. These acids are needed for many purposes. HCl is needed for the conversion of pepsinogen into pepsin which is essential for breaking down peptic bond in protein chains. For example, if HCl is low, some of the unbroken peptides reach the duodenum. Since the first phase of the digestion is not taken place properly, the rest of conversion also does not take place correctly and thus the macromolecules reaches the colon. This will cause the gut bacteria to continue with the rest of digestion and this bacterial digestion triggers gas formation.
Lipids also need acids for forming micells. Then only it can be absorbed by enterocytes. This acid is provided by the gall bladder from the liver.
So in essence, if stomach acids or bile acids are less, protein digestion and lipid digestion will be in trouble. This stage can be considered ‘mandagni’ or dull digestive stage will not be able to digest even smaller portions of food.
Acids are needed for the activation and propulsion of peristaltic movement. If acids are less peristaltic movement will be slow.
Note, this is a stage pitta low and Kapha high. We need to use pitta increasing and Kapha reducing food and medicine for example, ginger, pepper, cumin, etc
Excessive acids in the stomach can liquefy the mucus and make ulcerations in the stomach wall. If bile acids are high, the same thing can happen in small intestine as well. More over peristaltic movement will be faster and can lead to acid optic disorder and bleeding from stomach or intestines.
Note, this is a stage where pitta is high and Kapha is low. The use of bitter, sweet food and medicine will reduce Pitta and increase Kapha for example milk, licorice, dry grapes, sweats take bitter taste
This is stage Agni is influenced by Vata so the Agni production will be irregular. In vishamagni ,agni can be dull at times and sharp at other times this is the basic problem is mandagni. There will be less acids or excessive production of pitta. So the body pushes proteins and lipids to the colon, and the bacteria present in the colon will act on this Protein and lipids to cause gas. If the gas is not released through downwards, and it gets obstructed, the gas will move upward and reach stomach. In this upward movement even bile can reach the stomach. This will cause acidity or amlapitha. Ayurveda think this is a stage of tikshna Agni but actually this is a stage of vishamagani and has to balance the Agni instead of treating for excessive fire.
It is a stage of normal limit of the acids, alkali and neutral elements of the koshta.
Proper digestion and proper metabolism means good immunity!
Dr P.R. Vishnu, BAMS, MD is director of the Sivananda Institute of Health at the Sivananda Dhanwantari Ashram, Kerala, south India