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The term Dhatu (Samskrit: धातुः, Plural: धातवः) is used in 2 different contexts in Ayurveda. With reference to the Sharira (शरीरम् 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.
शरीर धातवः॥ Vital body tissues
Dhatus pertaining to the Sharira (physical body) are called as Sharira Dhatus (शारीर धातवः). 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.
व्युत्पत्तिः ॥ Etymology
The word ‘Dhatu’ is derived from the verb ‘Dha’ (धा) which means to hold.
धारणात् धातवः |
dhāraṇāt dhātavaḥ |
The matters which hold the body are termed as Dhatu.
In general, it is a term signifying bodily fluids and tissues.
धातु महात्म्यम् ॥ 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 (चिकित्सा | treatment modality) in Ayurveda is to establish the equilibrium of all the dhatus. They provide the seat for Doshas (दोषाः) and let them control the body. Strength of the Dhatus is the critical factor for one’s immunity and overall health.
सप्तधातवः ॥ 7 dhatus
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 totally comparable. 7 Dhatus described in Ayurveda compendium are as follows,
- Rasa (रस धातु) - The dhatu in liquid state, which is in the form of essence of nutrition and performs the function of providing nourishment and nutrition to the rest of the body. It is roughly correlated with lymph or plasma fluid.
- Rakta (रक्त धातु) - The dhatu in liquid state, which is called as Prana or life. Praised as the
- Mansa (मांस धातु) - 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 (मेद धातु) - 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 (अस्थि धातु) - 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 (मज्जा धातु) - 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 (शुक्र धातु) - 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.
धातुवृद्धिक्षय हेतवः ॥ Factors affecting metabolism of dhatus
धातवः पुनः शारीराः समानगुणैः समानगुणभूयिष्ठैर्वाऽप्याहारविकारैरभ्यस्यमानैर्वृद्धिं प्राप्नुवन्ति, ह्रासं तु विपरीतगुणैर्विपरीतगुणभूयिष्ठैर्वाऽप्याहारैरभ्यस्यमानैः॥ (Char. Samh Sha 6.9)
dhātavaḥ punaḥ śārīrāḥ samānaguṇaiḥ samānaguṇabhūyiṣṭhairvā'pyāhāravikārairabhyasyamānairvr̥ddhiṁ prāpnuvanti, hrāsaṁ tu viparītaguṇairviparītaguṇabhūyiṣṭhairvā'pyāhārairabhyasyamānaiḥ॥ (Char. Samh Sha 6.9)
Meaning: Dhatus get increased by the habitual use of food preparations which are either of similar attributes or are dominated by such attributes. Habitual use of food having opposite qualities or having elements that are predominantly of opposing qualities reduces the dhatus.
धातु विकृति प्रकाराः ॥ Pathological states of Dhatus
There are three types of pathological changes in these Dhatu viz. Kshaya (क्षयम् | decrease), Vṛddhi (वृद्धिः | increase) and Dushti (दुष्टी | 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 explicitly mentioned in Ayurveda classical treatises. However, the clinical features of Dushti (vitiation) are understood by studying the features of disturbed function of the Srotas (स्रोतसम् | physiological system) pertaining to the individual Dhatu. In this condition, the Dhatu increases at one place at the cost of other.
रसशास्त्रांतर्गते धातवः ॥ Dhatu in Rasashastra
The materia medica of Ayurveda includes various mineral and metallic substances as well. These metals and minerals are classified into various categories on the basis of their common features and application in pharmacology. Generally these drugs are classified into four distinct classes named- Rasas (रसाः), Dhatus (धातव्ः), Ratnas (रत्नाः) and Vishas (विषाः). The class of ‘Rasa’ is predominantly possessing ‘Rasayana’ (रसायनम् | 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.
Use of Dhatus
The therapeutic properties of metals like the Gold, Silver, Copper, Iron, Lead and Tin and alloy Bronze (Bell metal) are described by Acharya Sushruta. Although the mineral and metallic formulations are described in the classics belonging to ‘Samhita’ and ‘Post-samhita’ period, the processing technique of these materials in these periods differs considerably.
Rasashastra Dhatus: Metals in Ayurveda Iatro-chemistry
Following metals are considered under Dhatu category in Rasashastra. These metals are widely used in various classical Ayurveda formulations after rigorous processing and purification in order to make them bio-available to body tissues on oral consumption. This also assures safety and enhances efficacy.
- सुवर्णम् Gold (Suvarna)
- रौप्यम् Silver (Raupya)
- ताम्रम् Copper (Taamra)
- लोहम् Iron (Loha)
- नागः Lead (Naaga)
- वङ्गः Tin (Vanga)
- यशदः Zinc(Yashada)
- Ashtanga Hrudayam (Sutrasthanam Adhyaya 1 Sutram 13)
- 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
- Sushruta Samhita (Sutrasthanam Adhyaya 46 Sutra 326-330)