The term Dhatu is used in 2 different contexts in Ayurveda . With reference to the Sharira (body), Dhatus refer to those vital body tissues that are responsible to hold and sustain life. These are the basic building blocks of the physical body and they are 7 in number. On the other side, with reference to the pharmacology, Materia medica and Iatrochemistry in Ayurveda, Dhatus indicate ‘Metals’ like gold, silver, copper.
Sharira Dhatu (Vital body tissues)
Dhatus pertaining to the Sharira (physical body) are called as Sharira Dhatu. They are also considered as the vital body tissues.
Ayurveda states that 7 dhatus constitute the physical body of an individual. They have specific function in maintenance of life and they also perform the important task of nourishing the entire structure of the body. It is believed that, living body can not afford loss of any of these 7 dhatus to any extent and if it occurs, it leads to serious damage to the body. This damage could be either in the form of development of a disease or poor immunity leading to repeated episodes of ill health.
The word ‘Dhatu’ is derived from the verb ‘Dha’ which means to hold.
The matters which hold the body are termed as Dhatu.
In general, it is a term signifying bodily fluids and tissues.
Significance of Dhatus
Collectively they establish immune mechanism for the physical body. Their equilibrium is described as the state of health. Thus, the ultimate aim of any Chikitsa (treatment modality) in Ayurveda is to establish the equilibrium of all the dhatus. They provide the seat for Doshas and let them control the body. Strength of the Dhatus is the critical factor for one’s immunity and overall health.
It is important to know that, the dhatus in Ayurveda are correlated with body tissues for easy understanding for the first step. However, they are not similar. Ayurveda has identified various body tissues majorly on the basis of their unique function in the body than their morphological characteristics. Thus, Dhatus are also defined and described on the basis of their exclusive function. to some extent some of them can be roughly correlated with currently known body tissues but they are not totaly comparable. 7 Dhatus described in Ayurveda compendium are as follows,
- Rasa- The dhatu in liquid state, which is in the form of essence of nutrition and performs the function of providing nousrishment and nutrition to the rest of the body. It is roughly correlated with lymph or plasma fluid.
- Rakta - The dhatu in liquid state, which is called as Prana or life. Praised as the
- Mansa - The dhatu in more solid state, which performs the the function of covering the body and protecting from external environmental conditions. The term 'Mansa' literally means, flesh or meat thus it is usually correlated with the muscle tissue of the body.
- Meda - The dhatu in semi solid state, which performs the function of oleation and lubrication. The term 'Meda' refers to fat thus, this dhatu can be roughly correlated with fatty tissue of the body.
- Asthi - The solid tissue in the body which forms the basic function of holding the entire body and performing various movements. It forms the basic architecture of the body. Hence it is usually correlated with bony tissues in the body.
- Majja - The dhatu which is contained within and protected by the framework of Asthi dhatu. It is commonly correlated with bone marrow and nervous tissue in the body.
- Shukra - Shukra means bright, pure, and radiant. It can also mean the “essence” of something. In Ayurveda, the term is commonly used to describe both the male semen and the female egg, as they contain the essence of all of the other dhatus (tissues) of the body. Shukra is the seventh and final dhatu in the dhatus formation cycle.
Traditional texts often refer to the above as the Seven Dhatus (Saptadhatus). Ojas is known as the eighth Dhatu or quintessence of these 7 dhatus.
Pathological states of Dhatus
There are three types of pathological changes in these Dhatu viz. Kshaya (decrease), Vṛddhi (increase) and Dushti (vitiation). The Kshaya of the one and Vrddhi of other may be simultaneous in the same disease and in the same patient. Vrddhi and Kshaya symptoms are explicitely mentioned i Ayurveda classical treatises. However, the clinical features of Dushti (vitiation) are understood by studying the features of disturbed function of the Srotas (physiological system) pertaining to the individual Dhatu. In this condition, the Dhatu increases at one place at the cost of other.
Dhatu in Rasashastra (Metals in Ayurveda Iatro-chemistry)
The materia medica of Ayurveda includes various mineral and metallic substances as well. These metals and minerals are classified into vaarious categories on the basis of their common features and application in pharmacology. Generally these drugs are classified in to four distinct classes named- Rasas, Dhatus, Ratnas and Vishas. The class of ‘Rasa’ is predominantly possessing ‘Rasaayana’ (adaptogenic effect) effect. Dhatus are grouped together on account of their capacity to provide structural strength to the body. The minerals possessing gem quality are grouped as Ratna, whereas inherently highly poisonous plants are grouped as Visha. (Savrikar SS, Ravishankar B. Introduction to 'Rasashaastra' the Iatrochemistry of Ayurveda. Afr J Tradit Complement Altern Med. 2011;8(5 Suppl):66–82. doi:10.4314/ajtcam.v8i5S.1)
Use of Dhatus
(To be edited)The therapeutic properties of metals like the Gold, Silver, Copper, Iron, Lead and Tin and alloy Bronze (Bell metal) are described by Acharya Sushruta (Sushruta Samhitaa 1992b-Susruta Sutra 46/326-330). Although the mineral and metallic formulations are described in the classics belonging to ‘Samhitaa’ and ‘Post-samhitaa’ period, the processing technique of these materials in these periods differs considerably.
Following metals are considered under Dhatu category in Rasashastra. These metals are widely used in various classical Ayurveda formulation after rigorous processing and purification in order to make them bio-available to body tissues on oral consumption.
- Gold (Suvarna)
- Silver (Raupya)
- Copper (Taamra)
- Iron (Loha)
- Lead (Naaga)
- Tin (Vanga)