Agni (part 1 here)converts food to energy, which is responsible for all the vital functions of our body and so the source of life, complexion, strength, health, nourishment, lustre, ojas (vital-yet-subtle energy) tejas (fire and light)and prana. Balanced Agni
(neither too low, nor too high: just high enough to completely metabolise food, without leaving any of it undigested or half-digested) means perfect digestion and optimum health.
Main types of agni
There are 13 main types of agni (jatharagni, 5 types of bhootagni and 7 types of dhatvagni (dhatu agni)) in the body, although it must be remembered that agni is present in every cell of the body and in all cellular metabolic processes.
Food digestion process (Ahar parinam pak)
Firstly jatharagni in the stomach/ duodenum (gastric juices) breaks down food to aharasa, which is similar to a nutritional juice called quilo. (This metabolic process takes place in the gastrointestinal tract, up to and including absorption through the intestinal walls.) Aharasa, after being absorbed from the intestines, goes to the liver where it is further broken down by 5 types of bhootagni (akashagni, vayuagni, agniagni, jalagni, prithviagni) into a finer nutritive juice (rasa dhatu) which contains all the components of the dhatu.
Post-digestive tissue assimilation process (Dhatu parinam pak)
This fine nutritive juice can be considered preliminary rasa dhatu, which is further metabolized by rasa dhatu agni and separated out to form a) pure rasa dhatu (pure plasma); b) its upadhatu (sub-tissue/by product); c, preliminary rakhta dhatu (the subsequent tissue, blood); and d, mala (waste).
This rasa dhatu (along with prana collected from the lungs) is sent to the heart via Rasa vaha strota (strota are channels in the body belonging to specific systems, in this case plasma). It is then pumped by the heart to each of the seven dhatu through each respective strota. Here it´s important to understand that each of the 7 dhatu has its own agni (dhatvagni) and its own strota channel.
Each dhatvagni metabolises and extracts the components needed to manufacture and repair itself. Then these fine components are further metabolized by each dhatvagni to make the subsequent dhatu and in this process some dhatu upadhatu (sub tissue) and dhatu mala (waste) are formed too.
However the final dhatu, shukradhatu (reproductive tissue and hormones), is metabolised by shukra agni to create and repair itself and does not form either by products or waste but only ojus, the pure essence of the dhatu, life force or immunity.
What are the agni formed of?
They could be regarded as enzymes and all are created by their respective dhatu, which can be found through the whole body. For example, shukradhatu creates sex hormones which function through the whole body, though shukradhatu may be/is concentrated in the reproductive tissue. If dhatu are not made of good quality, it means the dhatvagni themselves will not be made of good quality either and so proper metabolic function may be affected..
Rasagni is present throughout rasadhatu, that is wherever it is circulating in the body. In fact it is formed of aharasa itself. It must be remembered that the function of all agni is not only to digest (break down the raw materials of food, aharasa and subsequent dhatu) but to transform, ie what is broken down to its basic molecules is built back up in ways the body can assimilate. (We can compare this to the breakdown of proteins into amino acids by peptides (enzymes) which will later recombine to form plasma, blood, muscle, fat, bone marrow and reproductive tissue.)
There is no organ which is only made of one dhatu, they are always mixed, eg muscle, bone, blood, Processes are happening continuously in all organs and cells of the body. All cells are metabolically active and taking part in many complex overlapping processes.
Dhatu parinam pak Transformation of tissues (tanmutras subtle qualities)
Dhatu Upadhatu (by products)
rasadhatu breast milk, saliva
rakhtadhatu bile, menstrual blood
asthidhatu nails, hair, teeth
majjadhatu eye gunk
shrukradhatu no waste, only ojas =immunity
Impairment of agni/type of imbalance
Mandagni 'slow' (hypo-functioning) due to Kapha, eg lactose intolerant, dyspepsia, indigestion, steatorrhoea (fat in the stools),
Tikshnagni 'sharp' 'quick' (hyper-functioning) due to Pitta, eg acid peptic disorder, Gastro-Eosophageal Reflux Disease (GERD/Acid reflux)
Vishamagni (erratic) due to Vata, eg Irritable Bowel Syndrome, Colic, Spasm, diarrhoea
What affects agni?
Stress, bio-rhythms, age, physical activity, and life-style all affect agni functioning. The quality of agni and metabolism decreases with age, more ama accumulates and the quality of dhatu also declines.We shouldn't challenge agni, but support it by choosing easily digestible foods, eating smaller portions, and eating at the right times of day, etc.
Agni can be deranged by the following:
1. Not enough ‘fuel’, in which case the fire goes out. This can result from a lack of food, the person may be starving for nourishment and lacks proper thinking capacity and knowledge.
2. Too much ‘fuel’, in which case the fire also goes out. This can be due to an overloaded system, eating when not hungry or already full, overthinking, overstimulation, too many thoughts, toxic thinking.
3. Not enough exercise puts the fire out. Some exercise should be taken every day for at least an hour, and it should be playful and fun, such as gentle sports, dance, yoga, swimming.
4. Too much physical or mental overload. Stress, whether physical or mental, working too hard, overthinking, overstimulation are all detrimental to the body. Too much exercise or exercising too hard also stresses the body. We should only exercise to 50% of our capacity and never to the point of breathing through the mouth. Even too much reading, travelling, internet, television, phone can also aggravate Vata and reduce agni.
5. Disease. By definition agni is low during illness, and so only easily assimilated foods like clear soups, rice soup, kichari should be taken in small portions. Rest is also advised.
It's good to remember that mental and emotional self-control and a positive attitude are important. Nervousness, grief and stress all affect agni, mostly by aggravating Vata. Remember to be an observer, don't allow anything to disturb you too much.
“You are only as healthy as your digestion” and “all disease begins in the gut” said Hipokratis.
“When food is digested improperly because agni [the digestive flame] is low the undigested food becomes vitiated [disturbed] and collects in the stomach. It is known as ama [toxins].” – Astangahrdaya Samhita