Meda Dhatu (मेद धातु)
Meda dhatu is the body component which indicates fat in general and adipose tissue in particular. Its important function is to oleate or lubricate (snehana). (SAT-B.435) In general, obesity or fat in the body is denoted by the word meda.
Functions of Meda Dhatu are- It lubricates every cell of the body which is important function of Meda Dhatu. It controls sweat formation. It provides strength, energy to the body. It controls dryness of Vata. Proper nourishment of Meda Dhatu gives proper shape to the body. It acts as a shock absorber. It protects body from excess cold or hot climate. In starvation, energy can be obtained from Meda Dhatu. When Kapha vitiates the Medovaha Srotas and Medodhara Kala, the Meda Agni becomes low and as a result the qualities of earth and water takes into the body are digested slowly, causing a greater amount of fatty tissue formation. When Pitta vitiates the Medovaha Srotas and Meda Dhara Kala, the Meda Agni becomes high, qualities of earth and water burned up quickly leading to little Meda formation
Panchabhautika constitution and properties
Meda dhatu has dominance of prithvi, jala and agni mahabhuta.
It possesses properties like unctuousness (snigdha) and heaviness(guru).
Metabolic by-products and waste products (Upadhatu and mala)
During the process of metabolism and formation of meda dhatu, ligaments (snayu) are formed as the metabolic byproducts (upadhatu). [Cha. Sa. Chikitsa Sthana 15/17]. Sweat and sebum are formed during this process as waste products (mala). [Cha.Sa. Chikitsa Sthana 15/18].
Characteristics of best quality of adipose tissue (meda sara )
The person endowed with best quality of meda dhatu has significant unctuousness specifically in complexion, voice, eyes, hair, skin hair, nails, teeth, lips, urine and feces. This indicates wealth, power, happiness, enjoyment, charity, simplicity and delicacy in dealings.[Cha.Sa.Vimana Sthana 8/106]
Channels of transportation and transformation of meda dhatu (medovaha srotas)
The channels of transportation and transformation of meda dhatu originate from the kidneys(vrikka) and omentum (vapavahana), [Cha. Sa. Vimana Sthana 5/8]
Sushruta opines that they originated from pelvic region(kati) and kidneys(vrikka).[Su. Sa. Sharira Sthana 9/12].
Vagbhata added mamsa dhatu to the origin with kidneys (vrikka).[A.S.Sharira Sthana 6/26]
Considering the above opinions, the origin of meda dhatu can be considered in pelvic region, omentum and kidneys. The sites of origin are important for knowing the source of nourishment in diagnosis and treatment.
The following structures can be considered as components of the transportation and transformation system of meda dhatu.
Functions
Meda dhatu is responsible for functions of lubrication(sneha), sweating (sweda), stability (dridhatwam), and nourishment of bone tissue(asthipushti). [Su. Sa. Sutra Sthana 15/5]
Importance in diagnosis
Causes of vitiation
The channels of transportation and transformation of meda dhatu (medovahasrotas) are affected by the sedentary lifestyle including lack of physical exercise, daytime sleep, excessive consumption of fatty food, and alcoholic drinks. [Cha. Sa. Vimana Sthana 5/16]
Importance of concept in the preservation of health and prevention
Meda dhatu provides unctuousness to all body components. Unctuousness is the essential property of the essence of all seven dhatu (ojas). It is related to vitality and immunity of the body. [Cha.Sa. Chikitsa Sthana 24/31] The unctuous portion (sneha) carries functions like lubrication, providing moisture, smoothening, unction, fluidity, and ooziness. [Cha.Sa.Sutra Sthana 22/11] These are important in various physiological processes and functions of the body.