Digestion and the formation of the dhatus (tissues) and byproducts
Rasa – essense, Rakta – blood, Mamsa – muscle, Meda – fat, Asthi – bone, Majja – nervous, Shukra – reproductive, these are all the seven tissues.
Kitta – waste products
Saar – Aahara Rasa – from here the “sukshma pachana”, subtle digestion begins.
Main purpose of saara is to give nutrients to all the dhatus. If aahara rasa decided it wanted to skip one dhatu (for whatever reason), would start to cause illness. Fasting for long periods of time can cause underformation of aahara rasa or the quality is to little to nourish dhatus. Just to maintain overall health and strength is the nourishment of all the dhatus.
Fermented things have effect on aahara rasa, spicy food in aahara rasa – every dhatu will then get that effect on it – so they will increase in heat. That’s why to develop shukra dhatu, you should have unctuous things not because it immediately increases the shukra dhatu, but because in general the aahara rasa will be more unctuous and will get to the shukra dhatu.
Then nutrition is given to every dhatu in a very specific manner.
The process of dhatu nourishment is solely dependent on the agni of each dhatu. If agni is good, the dhatu will be able to accept the aahara rasa. That is called dhatu agni. This agni is so important to take nutrients from aahara rasa to replenish rasa dhatu. If this agni is weak, the aahara rasa either won’t reach it or will come in a disturbed form. If the agni is the door, if the door is not open, the nutrients won’t reach the dhatu. Like a mailman trying to deliver mail to a closed door. Acts as a filter so that only the best quality of aahara rasa will enter into the channel. Quality of aahara rasa is very important too. Agni of rasa dhatu is important to convert aahara rasa into rasa dhatu. At level of dhatus it’s the dhatu agni.
Aahara Rasa -> Rasa agni -> rasa dhatu + kapha as mala + upadhatu/byproduct of stanya and raja – this dhatu is responsible for the production of the kapha dosha for the whole body. Even though we call kapha a mala, this is not a mala that is going to be excreted – it is the main source of healthy kapha in the body. Kapha mala in this case could be called another byproduct in this case. It is called a mala because it is not relevant to the formation of the rasa dhatu. This particular mala is used everywhere else in the body though.
Part of aahara rasa is getting converted into 3 products – Rasa dhatu, kapha, stanya (breastmilk) & raja (menstrual fluid). But we still have more aahara rasa that is getting converted to other dhatus. Kapha stays in rasavaha srotas but slowly moves to other parts of the body. Because of the presence of kapha in the srotas we can say that rasa and kapha are closely identified.
Aahara Rasa then moves onto Raktavaha Srotas and acts on Rakta agni -> Raktadhatu + upadhatu of Sira & Kandara (vessels and tendons) + Pitta as the mala. Generating three things as always – dhatu + 2 byproducts. This pitta that gets generated is the main pitta of the body, and forms the main pitta required for basic physiology, including alochaka pitta, sadhaka pitta etc. Is the main reservoir of pitta, but doesn’t form them all here in this srotas. Instead goes all over the body.
Aahara rasa then goes to mansavaha srotas and acts on the mansa agni which then forms mansadhatu + kha-mala (akasha) mala (earwax and nose boogers) + upadhatu of Tvak (skin). Getting formed means replenishing present amount of dhatu, because you use it all the time. The replenishing action of the body.
Aahara rasa then goes to medavaha srotas and agni of meda dhatu acts on it and forms medadhatu + Snayu (muscle) upadhatu + sweda (sweat) mala. What we call muscles though are formed of 3 dhatus: the bulk of muscle is meda dhatu, mansa dhatu forms muscle sheath and rakta dhatu forms tendons. Sweat gets excreted, but must be excreted properly when it is needed. Ex. Don’t profusely sweat when its 30 degrees outside – if they do, then something is wrong with body. The sweda has a specific course to follow. When temperature is hot, function of sweda in body is to cool the body. Not just the waste to be thrown out of the body. In the same way, stool and urine also are specific to body and reason for proper elimination is important. Even though its mala, there are certain functions. In case of TB rajakshma, all the nutrients are stuck in kitta, and not forming saara. That is why it is recommended in TB to not follow normal urge to defecate. Should hold stool for some time as long as possible to uptake more nutrients. In this case stools are having an important function in the body. Even though we call it a mala, it has some functions in the body.
Blood is flowing everywhere, but within its limits – those limits are defined by the srotas. Muscles are everywhere in body, but aren’t in bones for example. The muscles are defined by the srotas. Blood is flowing everywhere but stays within its blood vessels, therefore still within its srotas. Looking at the cardiovascular system, the blood is everywhere but within its own system. Same thing is true with bones – there aren’t bones in eyes, or muscles because stays within its srotas. Srotas is the completeness of the system rather than a specific anatomical portion.
Aahara rasa then goes to Asthivaha srotas, acting on the asthi agni and forming Asthi Dhatu, the Upadhatu is teeth, the mala is Kesha, Nakha and Loma – hair, nails, and bodyhair. Could be in minute form but is still always there. Ridges in nails could be associated with issue of asthi dhatu. In old age, loss of teeth, asthi dhatu depleted and vata increasing.
Aahara rasa then goes to majjavaha srotas, acts on the majja agni and forms Majja Dhatu and the mala of Akshivit sneha – which means sneha of akshi/eyes and sneha of vit/feces (unctuousness which facilitates the flow of fecal matter – translates to the unctuousness in the lining of the colon).