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

Fig.1: Agni and Pitta dosha

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), tejasa (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.

Fig.2: Three classes of agni

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

All three classes with thirteen agni are interconnected and interdependent. The energy mechanism takes place in every body cell. This shows agni is present in every cell. Mitochondria are the powerhouse of the cell. The release of adenocine tri phosphate (ATP) to give energy is an example of agni working at cellular level.

II. Four types of digestive patterns

Based on the intensity of action, agni is further classified in to four categories as below.

1. High intensity or quick digestion (tikshna): It can tolerate all types of irregularities in the diet. It is seen in pitta dosha dominant constitution.

2. Low intensity or slow digestion (manda): It cannot tolerate even slight irregularities. It is seen in kapha dosha dominant constitution.

3. Normal intensity or normal digestion (sama): It is average intensity and maintains equilibrium. It is seen in an individual with a balanced dosha constitution.

4. Irregular intensity or unpredictable digestion (vishama): It is an unpredictable form that sometimes can or cannot tolerate irregularities. It is seen in vata dosha dominant constitution. [ Cha.Sa. Vimana Sthana 6/12]

The intensity of digestion is assessed on the basis of time taken for digestion of food. 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 the digestive pattern of that individual. Accordingly, four types of ‘digestive patterns’ are observed in clinical practice. In ayurvedic practice, the treatment protocol aims towards maintaining the equilibrium status of agni through diet, lifestyle and medicine. The exact relation of these digestive patterns with phenotypic variations, epigenetic pathways and intestinal microbial flora needs more research to understand precisely.

Location

The jatharagni is located in the the gastrointestinal tract (koshtha). The lower part of the stomach and duodenum (grahani) is the main site where the initial digestive process occurs. [Cha.Sa. Chikitsa Sthana 15/56-57], [Su.Su.21/10], [A.Hr.Sha.3/50] The bhutagni mainly works in the liver and hepato-biliary system. Dhatvagni are located and work at their respective abodes of body tissues.

Properties

Agni possess similar properties like agni mahabhuta. These properties are as follows:

• Hot (ushna)
• Sharp (teekshna)
• Subtle (sukshma)
• Light (laghu)
• Dry (ruksha)
• Clear (vishada)[Cha.Sa.Sutra Sthana 26/11]
• Rupa (vision) [Cha.Sa.Sharira Sthana 1/27]

Functions of agni

The important function of agni is digestion and transformation of ingested food substance to biologically acceptable form. Agni produces the essence or useful part of the food (anna rasa) and the waste part of the food (kitta bhaga). [Cha.Sa. Sutra Sthana28/4] The essence of food is then circulated further for processing by bhutagni and dhatvagni. The waste part leads to formation of excretory products (mala) including stool (purisha), urine (mutra) and sweat (sweda).

The bhutagni acts for selective uptake of their corresponding components of food. Similarly, dhatvagni acts for selective transformation of food component into the respective body tissues. The waste products formed in this process lead to formation of metabolic wastes (dhatu mala) at various levels. Thus, agni plays vital role in formation and nourishment of body tissues. Apart from digestion and metabolism, agni plays essential role in thermo-regulation, normal complexion, energy generation, strength and immunity. Agni reduces the bulk and moisture. Thus, combustion and reduction are functions of agni.

Physiological factors supporting agni

Dosha are the main functional unit of human physiology. Dosha also govern the physiology of digestion. Samana vayu acts on jatharagni (the digestive factors) and kindles agni. [Cha.Chi.28/8] Prana vayu and apana vayu support the functions of agni. Pachaka pitta, devoid of liquid property, is responsible for digestion.[A. Hr. Sutra Sthana 12/10-11] Kledaka kapha is responsible for moistening the ingested food. Thus, the process of digestion is driven by dosha. Factors responsible for the complete transformation and absorption of food (ahara parinamakara bhava) explain this phenomenon in-depth. [Cha. Sa. Sharira Sthana 6/14], [Cha.Sa. Chikitsa Sthana 15/6-8]. The vitiated dosha leads to the formation of ama.

Some researchers include the following factors under categories of physiological factors of Ayurveda :

Kledaka kapha: Mucin

Pachaka pitta: Various digestive enzymes like trypsin, chymotrypsin, pancreatic amylase, pancreatic lipase, cholesterol esterase, maltase, pepsin etc.

Samana vayu: Enteric nervous system, sympathetic & parasympathetic supply of Autonomous nervous system.

Factors influencing agni

Fig.3: Factors influencing agni

I. Diet

1. Quantity of diet

Food acts as fuel for agni. Food in proper quantity in accordance with agni (yatha agni abhyavahara) promotes digestion. Unsuitable food at an improper time and improper quantity (vishamashana) impairs digestion. [Cha.Sa. Sutra Sthana 25/40] Suitable variation in the quantity of food helps to maintain proper digestion and metabolism. The quantity further depends on 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.

2. Tastes

The sour taste (amla rasa) and pungent taste (katu rasa) kindle agni. [ Cha.Sa. Sutra Sthana 26/4]

3. Variety of forms of food

Different types of wholesome foods ingested in the form of eatable, drinkable, lickable and masticable stimulate the antaragni (digestive process). [Cha.Sa. Sutra Sthana 28/3]

4. Oleation therapy or fats

The unctuous or fat portion of food enhances taste, stimulates and expedites digestion. [Cha.Sa. Vimana Sthana 1/25.2] The oleation theapy (snehana) is prescribed before purification process to correct digestion. [Cha.Sa. Sutra Sthana 13] Administration of fat in moderate quantity is advised to kindle digestion in low digestive process. It is contraindicated in persons with polyphagia or aggravated pitta.

II. Pathophysiological conditions

5. Status of pitta dosha

Individuals with highly aggravated pitta dosha in duodenum have excessive digestive strength. Therefore, are able to digest and metabolize fats easily. [Cha.Sa. Chikitsa Sthana 15/70] The circadian variation of pitta dosha may also influence the status of agni.

6. Purification procedures

The digestion is weakened after administration of purification procedures. Therefore, a specific diet pattern (sansarjana krama) is prescribed to correct digestion as a follow up protocol. [Cha.Sa. Sutra Sthana 15/16]

7. Excess fat deposition or corpulence (aavarana of vata dosha by meda)

Due to the obstruction of body channels by medas, the movement of vata is specially confined to koshtha (gut). This results in stimulation of agni and rapid digestion of food. Hence, the person quickly feels hunger pains and suffers from voracious appetite. [Cha.Sa. Sutra Sthana 21/5-6]

8. Exercise

Physical exercise enhances digestion and metabolic processes. [Cha.Sa. Sutra Sthana 7/32] Therefore, one shall follow exercise as per the status of agni to maintain equilibrium and health.

III. Environmental conditions

9. Seasons

The changes in atmosphere influence agni. The strength of agni is low in rainy season. Hence, measures promoting agni and light to digest food is prescribed in seasonal regimen of rainy season. [Cha.Sa. Sutra Sthana 5/34] In winter season, the strength of agni is good. Hence, heavy to digest food in good quantity is prescribed in the seasonal regimen. [Cha.Sa. Sutra Sthana 6/9] These examples show environmental conditions can influence the digestion and metabolism.

10. Age

The strength of agni is at peak in young and middle age. It is low in old age. The ageing process adversely affects agni. Hence, the food pattern shall be modified as per age.

Assessment of agni

Assessment of agni is an essential component in the maintenance of health as well as in treating diseases. Agni is subjectively inferred from capacity of digestion. [Cha.Sa. Vimana Sthana 4/8, 8/40] Various attempts are made to develop tools to assess agni.

Singh A, Patwardhan K. et. al. developed and validated a self-assessment tool to estimate strength of agni. The study also evaluated 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 to assess the digestive functions (agni) during the administration of snehana (internal oleation).

Agni performs various functions of digestion, metabolism and assimilation. Gastric secretion is a digestive fluid, formed in the stomach and contains 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). Its relationship with the acidity of gastric secretions was observed 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.

Causes of impairment of agni (agni dushti)

Following are the causes of impairment of agni.

Dietary habits

• Excessive starvation
• Taking food in a state of indigestion
• Overeating
• Irregular habit of eating
• Eating unwholesome food
• Excess intake of heavy to digest food and excessive nourishment
• Food with cold quality or eating chilled or frozen items
• Food which is dry in nature or food which brings about emaciation
• Contaminated food
• Excess water intake [Ma.Ni. Agnimandya Nidana]

Iatrogenic causes

• Improper administration of therapeutic emesis (vamana), purgation (virechana) and oleation (Sneha)
• Improper administration of unctuous enema (anuvasana basti) [Cha.Sa. Siddhi Sthana 4/ 49]

Psychological causes

• Eating food with negative emotions like worries, grief, fear, anger [Cha.Sa. Vimana Sthana2/9]

Other causes

• Emaciation of body due to disease
• Sudden change in environmental conditions or migration to unsuitable place, time zone and season
• Suppression of natural urges [Cha.Sa. Chikitsa Sthana 15/42-43]
• Day time sleep [Cha.Sa. Sutra Sthana 21/46]

Clinical features

The vitiation of agni leads to improper digestion and metabolism. It forms a toxic metabolic product called ‘ama visha’. This leads to a state of indigestion and its clinical features. It leads to disorders of digestive system (grahani), if not treated on time. [Cha.Sa. Chikitsa Sthana 15/44-45]

The vitiation of agni is observed in various diseases as follows:

• Depletion of agni (agni sada) in disorders of vitiation of blood (rakta dhatu) [Cha.Sa. Sutra Sthana 24/13]
• Impaired functions of agni (upahata agni) in jwara(fever and associated diseases) [ Cha.Sa. Nidana Sthana1/23] [Cha.Sa. Chikitsa Sthana 3/102]
• Irregular pattern of agni (agni vaishmya) is seen in gulma [ Cha.Sa. Nidana Sthana 3/15]
• Impaired agni is observed in rajayakshma (tuberculosis) [ Cha.Sa. Chikitsa Sthana 8/41], udara (abdominal diseases including ascites) [ Cha.Sa. Chikitsa Sthana 13/9] hemorrhoids (arsha) [Cha.Sa. Chikitsa Sthana 14/244-246], diarrhoea (atisara) [Cha.Sa. Chikitsa Sthana 19/7], morbid thirst (trishna) [Cha.Sa. Chikitsa Sthana 21/63] and obstruction of udana vata by apana vata [Cha.Sa. Chikitsa Sthana 28/210]
• Various disorders due to ama dosha like enteritis (visuchika) and sluggish bowel (alasaka) are caused due to low digestion by agni [Cha.Sa. Vimana Sthana 2/10]

The diseases due to vitiation of agni can be categorized as following:

1. Vitiation of jatharagni: Disorders of digestive system, indigestion, acid peptic diseases, irritable bowel syndrome

2. Vitiation of bhutagni: Disorders in carbohydrate, fat and protein metabolism at hepatic level, disorders due to fluid and electrolytes imbalance

3. Vitiation of dhatvagni: Disorders of tissue metabolism and systems related to various dhatu and srotasa The respective biomarkers and diagnostic assessment tools can be utilized to understand pathophysiology of these diseases.

Management of disorders due to impairment of agni

I. Lowered state of agni

The lowered functions of agni can be managed by administration of low dose of unctuous substance (sneha) to kindle it. Deepana (stimulation) of agni is the main therapy. Various dietary recipes, lifestyle modifications, panchakarma therapies and medicines are prescribed in management of grahani are prescribed for restoring equilibrium state of agni. [Cha.Sa. Chikitsa Sthana 15] The food, beverages and medicines with hot potency, sour and pungent taste are prescribed to kindle agni. Langhana (therapeutic fasting) is an important measure in the management of vitiation of agni. [Cha.Sa. Chikitsa Sthana 3/276]

Food and beverages to kindle agni

• Lukewarm water [Cha.Sa. Vimana Sthana 3/40]
• Manda (thin soup) [Cha.Sa. Sutra Sthana 27/254]
• Curd [Cha.Sa. Sutra Sthana 27/225]
• Butter [Cha.Sa. Sutra Sthana 27/230]
• Ghee [Cha.Sa. Sutra Sthana 27/231]
• Meat of common quail (lava bird) [Cha.Sa. Sutra Sthana 27/69]
• Fresh ginger (zingiber officinalis) [Cha.Sa. Sutra Sthana 27/166], powder of dried ginger [ Cha.Sa. Sutra Sthana 27/296]
• lemon/ jambira (Citrus limon (Linn.) Burm.F) [Cha.Sa. Sutra Sthana 27/167]
• Varieties of wines like arishta (prepared from medicinal decoction), pakwarasa( prepared from sugarcane juice), gauda( prepared from jaggery) [Cha.Sa. Sutra Sthana 27/179-195]
• Gruel-water (manda) [Cha.Sa. Sutra Sthana 27/251]
• Thin gruel (peya) and gruel water (manda) of roasted paddy [Cha.Sa. Sutra Sthana 27/254-255]
• Sesame oil [Cha.Sa. Sutra Sthana 27/287]
• Black pepper (maricha) [Cha.Sa. Sutra Sthana 27/298]
• Asa foetida (hingu) [Cha.Sa. Sutra Sthana 27/299]
• Rock salt (saindhav) [Cha.Sa. Sutra Sthana 27/300]
• Celery seeds (karavi, Carum bulbocastanum W.Koch.), black cumin (kunchika, Nigella sativa Linn.), cumin (ajaji, Cuminum cyminum Linn.), bishops weed (yavani, Trachyspermum ammi Linn.), coriander (dhanyaka, Coriandrum sativum) and Indian tooth-ache tree (tumburu, Zanthoxylum armatum DC). [Cha.Sa. Sutra Sthana 27/307]
• Alkali (kshara) [Cha.Sa. Sutra Sthana 27/306]
• Sequential administration of thin gruel, thick gruel kindles agni after purification procedures as dietary regimen [ Cha.Sa. Siddhi Sthana 6/57]

Medicinal formulations

• Talisadi churna [ Cha.Sa. Chikitsa Sthana 8/148]
• Shadava recipe (an ayurvedic formulation) [Cha.Sa. Chikitsa Sthana 11/90]
• Chiktrak ghritam [Cha.Sa. Chikitsa Sthana 12/58-59]
• Phalarishta [Cha.Sa. Chikitsa Sthana 14/153-157]
• Dashamuladi ghrita [Cha.Sa. Chikitsa Sthana 15 /82-86]
• Panchamuladi churna or ghrita [Cha.Sa. Chikitsa Sthana 15/88-93]
• Kshara ghrita [Cha.Sa. Chikitsa Sthana 15/168-172]
• Agastya haritaki avaleha [Cha.Sa. Chikitsa Sthana 16 /137]

Therapeutic procedures

• Therapeutic purgation (virechana) [Cha.Sa. Siddhi Sthana 1/18]
• Therapeutic enema with decoction (niruha basti) [Cha.Sa. Siddhi Sthana 1/42]

Treatment for excess agni

Excess agni is generally caused due to vitiation of pitta dosha. Hence treatment of pitta dosha is prescribed. The other condition is obstruction of vata dosha by excess fats (medasavritta vata), it causes excess stimulation of agni and polyphagia. This condition is treated with reducing therapy for fats (meda dhatu). It normalizes vata dosha and reduces appetite.

• Paravata fruit (Garcinia cowa ROxb.) is used to reduce agni. [Cha.Sa. Sutra Sthana 27/134]
• The alangy / ankota phala (alangium salviifolium (Linn.F.) Wang.) is used to reduce excess heat caused by agni. [Cha.Sa. Sutra Sthana 27/159]
• Peya (thin gruel)
• Therapeutic purgation (virechana) [Cha.Sa. Siddhi Sthana 1/18]

Future areas of research

Research is needed to study the biological effects of various factors mentioned above. The role of hormones like insulin, thyroid hormones, growth hormones in regulating tissue metabolism is well studied. However, the pharmacological effect of various dietary recipes, lifestyle factors and medicinal formulations on these hormones needs to be elaborated. The focused study on relation of agni with theories of epigenetics, inflammation, gut microbiome can produce insightful outcomes and new treatment options. The personalized medicine and personalized diet patterns depend completely of individualistic patterns of agni. The concept can provide leads beyond current theories of calorie consumption and nutrition.

The effect of agni on thermoregulation, bio-energetics, pharmacological mechanisms are some key areas of research.

Theses done

1. Correlation of Jaṭharāgni and Dhātvagni by S.N.Tiwari, Dept. of Kāyacikitsa, Banaras Hindu university, Varanasi,1969 2. Relation of Jaṭharagni and Dhātvagni clinical and experimental study by A.K.Mishra, Dept. of Kāyacikitsa, Banaras Hindu University, Varanasi, 1972. 3. Concept of Jaṭharāgni by Tiwari Ashutosh, Dept of Basic Principles, Banaras Hindu University, Varanasi, 1980. 4. Agni Vivecana by Govind Ram Paysi, Dept. of Basic Principles, N.I.A. Rajasthan University Jaipur, 1985. 5. Concept of Dhātu and Dhātvagni W.S.R. to Asṭhi dhātu and Asṭhyāgni By Madhavilatta G. Bhatt, Dept. of Basic Principles, I.P.G.T.& R.A. Jamnagar,1995. 6. Doşadhātumalakşayavŗddhivijñānīya Adhyāya of Suśruta Saṃhitā & Assessment of the principle “Pūrvah pūrvoativŗddhatvātvardhayeddhi param” in context of Raktakşaya by Vaibhav Dadu, Dept. of Basic principles, I.P.G.T.& R.A. Jamnagar, 2007.

Related chapters

Grahani Chikitsa Adhyaya, Trividhakukshiya Vimana Adhyaya

 Page under construction