Agni

‘Agni’ literally means fire. In Ayurveda biology, agni denotes all factors responsible for digestion and metabolism/transformation. (Code:SAT-B.488) It is the heat (ushma) generated from pitta dosha in the body. Therefore, all functions of agni are similar to pitta dosha. In panchamahabhuta (five fundamental elements), agni mahabhuta is the fire element. It is responsible for the transformation or change in the form of an element. This agni mahabhuta in macrocosm is represented by agni in microcosm of human body.

Contributors

Chapter/topic	Health / Agni (digestion capacity and digestive health)
Author	Deole Y.S.
Reviewed by	Basisht G.
Affiliations	Charak Samhita Research, Training and Development Centre, I.T.R.A., Jamnagar
Correspondence email:	carakasamhita@gmail.com
Date of first publication:	September 13, 2021
DOI	Awaited

Importance

Agni is a crucial factor in life. Diminution of agni is life-threatening. Normal functioning of agni leads to longevity. [Cha.Sa. Chikitsa Sthana 15/4] Sustenance of life, complexion, strength, health, nourishment, luster, ojas, teja (energy) and prana (life energy) depend on the status of agni in the body. [Cha.Sa. Chikitsa Sthana 15/3] The quantity of diet is decided by agni. [Cha.Sa. Sutra Sthana 4/3] The digestion of food, metabolism, transformation, and nutrition of tissues depend on status of agni.

It is an important factor for the assessment of health and disease. [Cha.Sa. Vimana Sthana 8] State of equilibrium of agni is an important component of health. [Su.Sa. Sutra Sthana 13/41] All diseases are caused due to impaired agni. [Cha.Sa. Chikitsa Sthana 13] Proper metabolism is key to good health. Agni is the energy that drives all metabolic processes. Selection of medicine, route and time of administration is decided based on agni of the individual. The preparatory procedures of panchakarma like oleation therapy (snehana), dose of unctuous medicine, purification protocol and its follow up measures are subjected to assessment of agni.

The acceptance of macro and micronutrients in the body depends on the status of agni. It is a crucial factor for nutrition. Apart from gross digestion and metabolism, agni is responsible for bio-energetic and biochemical transformations in the body. The relation of agni with gut microbiome can be studied to explore new insights in medical treatments. This article describes the concept of agni in Ayurveda texts and its applications in current medical science.

Meaning

Etymological derivation

The word ‘agni’ is made of three words. Agni = A + G + Ni. The word “A” denotes root “I,” meaning “to go”; “G” denotes the root “Ajna,” meaning “to glitter” or root “daha,” meaning “to burn” and “Ni” means “to carry.” It denotes agni moves everywhere and metamorphoses substances, burns, assimilates, glitters, and grows.

Synonyms

Vanhi, pawaka, anala, vaishvanara, tejasa, shikhi

Agni and pitta dosha

Agni is present in the form of pitta dosha in the body. [Cha.Sa. Sutra Sthana 12/11] [Su. Sa. Sutra Sthana 21/9] It is a separate entity than pitta dosha as observed through various references. Pitta dosha can be considered as the facilitator for the process of agni.

Classification

I. Three categories of agni

Agni is classified into three main classes like:

1. Jatharagni (present in the gastro-intestinal tract). This includes factors responsible for digestion and metabolism at gastro-intestinal tract level.

This agni is responsible for all amylolytic, proteolytic and lipolytic enzymes secreted by various exocrine glands in the gut, which actually cause digestion, i.e., breaking down different macromolecules into their constituent units.

2. Bhutagni has five fundamental elements, corresponding to respective mahabhuta. Those are: parthiva (pruthvi mahabhuta dominant), apya (apa mahabhuta dominant), taijasa (teja or agni mahabhuta dominant), vayavya ( vayu mahabhuta dominant) and nabhasa ( akasha mahabhuta dominant). They act on the corresponding substrate based on mahabhuta composition to make them homologous to body constituents. This includes factors responsible for digestion and metabolism at the organic level. Five types of bhutagni act after jatharagni, but before dhatvagni on the food and its metabolites. This represents the basic metabolism of various food components and minerals at hepatic level like carbohydrate, protein and fat metabolism.

This agni carries out the absorption of nutrients in the liver, which plays an essential role in metabolism. Several processes such as trans-amination, de-amination, beta-oxidation of fatty acids, glycolysis etc. take place in the liver. Therefore, the overall intermediary metabolism (involving fats, carbohydrates and proteins) can be understood as the functioning of the bhutagni.

3. Dhatvagni is present in the seven body tissue components (rasa dhatu, rakta dhatu , mamsa dhatu, meda dhatu, majja dhatu, asthi dhatu and shukra dhatu) and is responsible for transformation of one dhatu into another namely rasagni, raktagni, mamsagni, medo-agni, majjo-agni, asthi agni and shukra agni. This includes factors responsible for digestion and metabolism at dhatu (various tissues). This includes the endocrine and exocrine secretions, neurotransmitter and other chemical factors.

The small portions of agni are present in each dhatu. The increase or decrease of these agni leads to depletion or overproduction of dhatu respectively. [A.Hri. Sutra Sthana 11/24] This suggests the negative feedback and autoregulatory mechanism of agni. All hormones (such as insulin, growth hormone, thyroid hormones, testosterone etc.) that promote the transportation of various nutrients into the cells, along with the enzymes participating in the Kreb’s cycle, are to be included under the term dhatvagni. 4

Classes

• Jatharagni: The factors responsible for digestion and metabolism at gastro-intestinal tract.

• Bhutagni : The factors responsible for digestion and metabolism at organic level. These are five types of agni, those act after jatharagni, but before dhatvagni on the food and its metabolites. They are: parthiva (pruthvi dominant), apya (aap dominant) , taijasa (teja or agni dominant), vayavya (vayu dominant) and nabhasa (akasha dominant). They act on the corresponding substrate based on mahabhuta composition to make them homologous to that of the bodily constituents.

• Dhatvagni: The factors responsible for digestion and metabolism at dhatu (various tissues). This is responsible for transformation of one dhatu into another namely rasagni, raktagni, mamsagni, medo-agni, asthi agni and shukra agni. Thus, dhatvagni are seven.

Types

The intensity of agni is influenced by dosha and is of four types:

1. Sama (normal, due to the balanced state of all three dosha)
2. Vishama (irregular due to the dominance of vata)
3. Tīkshna (intense due to the dominance of pitta)
4. Manda (low due to the dominance of kapha)

The first type of normal digestion (samagni) needs 12 hours (4 yama) for complete digestion of food, and 6 hours (2 yama) for proper digestion of medicine. [A.S. Sutra Sthana 11/53] The time taken for complete digestion suggests digestive pattern of that individual.

Physiological relation of dosha and agni

Dosha are the main functional unit of human physiology. Dosha also govern the physiology of digestion. Samana vayu functions nearby the abode of digestive factors (jatharagni), kindles agni. Prana vayu and apana vayu supports the functions of agni. Pachaka pitta when devoid of its liquid property, is responsible for digestion.[A. Hr. Sutra Sthana 12/10-11] Kledaka kapha is responsible to moisten the ingested food. Thus the process of digestion is driven by dosha. Factors responsible for complete transformation and absorption of food (ahara parinamakara bhava) explain this phenomenon in-depth. [Cha.Sa.Sharira Sthana6/14],[Cha.Sa.Chikitsa Sthana 15/6-8]. The vitiated dosha leads to the formation of ama.

Importance and assessment of agni

The proper quantity of food depends on the strength of agni (factors responsible for digestion and metabolism). The strength of agni varies according to season, age and other factors. Thus the amount of food will also vary as per the power of agni. Suitable variation in quantity of food helps maintaining proper digestion and metabolism. The quantity further subjects to heavy to digest (gurutva) and light to digest (laghutva) nature of food. Nourishing benefits of diet is subjected to the status of agni. Thus agni is an important facilitator between health and food. Assessment of the status of agni is an essential component in maintenance of health as well as while treating diseased conditions.

Singh A, Patwardhan K. et. al. developed and validated a self-assessment tool to estimate strength of agni. The study also evaluates the practical utility of developed tool by recording serum lipid parameters. Lipid parameters vary significantly according to the status of [agni]].

Eswaran H. T. et. al. prepared an agni assessment scale comprising 64 questions to evaluate the four types of agni. The study has validated a scale for internal consistency.

Patil VC, Baghel MS et. al. developed formulae for assessment of the digestive functions (agni) during administration of snehana (internal oleation).

Agni performs various functions of digestion, metabolism and assimilation. Gastric secretions is a digestive fluid, formed in the stomach and contain numerous compounds including hydrochloric acid (HCL), pepsin, lipase, mucin. Kulatunga et al assessed the status of agni in the patients of pandu (anemia and blood deficiency disorders) and find out its relationship with the acidity of gastric secretions by use of fractional test meal examination. Their study concluded that HCL reduction in patients of anemia seriously affects the protein and iron absorption; thus Hypochlorhydria (found in 72.8% of the patients) indicates hypofunction of agni.

Related chapters

Grahani Chikitsa Adhyaya, Trividhakukshiya Vimana Adhyaya

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