Dhātus
Āyurvedic literature describes seven tissues (dhātus) of the body as products of food transformation.
Rasa (plasma):
Carries nutrients of digested food to nourish tissues, organs, and systems of the body.
Rakta (blood)
Carries oxygen and nutrients to the tissues and waste products away from them. Blood, poured into a test tube and treated with salt, separates into three distinct layers. At the top is plasma, a clear, gold liquid. In the middle is a solid band of white cells. At the bottom is a thick band of red cells.
Mamsa (muscle)
Covers vital organs, moves joints, helps in maintaining bodily strength, plays a role in metabolic processes.
Meda (fat)
Lubricates the tissues.
Asthi (bone)
Supports bodily structures.
Majjā (marrow)
In the bone hollows. Produces blood cells and platelets which repair blood vessels.
Shukra-male / Ārtava-female
(reproductive tissue):
The final physical manifestation of food transformation.
In the formation of tissues, Āharā rasa is the precursor to nutrients that 'feed' the dhātus and is the end result of the digestion of food. All of the dhātus and their agni then perform the transformation of asthāyi (immature, unripened) tissue into sthāyi (mature, ripened) tissue. Sthāyi (mature, ripened) rasa is formed within 5 days from āharā (unripened) rasa, which is formed within 12 hours after the ingestion of nutrients.Then in 10 days sthāyi rakta dhātu (mature, ripened) is formed; in 15 days, sthāyi mamsa dhātu; in 20 days, sthāyi meda dhātu; in 25 days, sthāyi asthi dhātu; and in 30 days, sthāyi majjā dhātu. It takes approximately 35 days after the ingestion of nutrients for sthāyi shukra or ārtava dhātu to be formed.
The eighth manifestation of food transformation is a fine essence, Ojas, at the juncture between consciousness and matter which is enlivening and regenerative. Its influence strengthens the body's immune system and imparts the radiance of vital health. It energizes the mind, contributes to powers of concentration and intellectual discernment, manifests as spiritual magnetism, and empowers resolve to experience rapid spiritual unfoldment and liberation of consciousness.
In the process of ripening of the tissue of each dhātu, three products are formed. The first of these is called sāra, pure sthayi dhātu. The next two are the upadhātu (superior byproduct) and the mala (inferior byproduct). Please note that although mala is commonly taken to mean 'waste', in Āyurveda 'waste' or mala serves a function. the table below shows these byproducts.
Note: Poshaka means 'nourishing'. Therefore, the malas of Rasa and Rakta dhātu nourish Kapha and Pitta doshas, respectively.
Please remember that there are two types or stages of each dhātu: asthāyi, the immature and unripened stage; and sthāyi, the mature, ripened stage. An important note to remember is that the sthāyi form of a particular dhātu is formed at the same time as the asthāyi form of the next or subsequent dhātu. For example: the sthāyi form of rasa dhātu yields to the asthāyi form of rakta dhātu. This process continues with the dhātus that are nourished sequentially afterward.
prīṇanam jïvaṇam lepah sneho dhāraṇa pūraṇe
garbhotpādaśca dhātūnām śreṣṭam karma kramāt smṛtam
Nourishment, maintenance of life function, plastering, lubricating, support, filling the space, and production of the embryos are the important functions of each dhātu, respectively.
Āyurvedic Sūtra