Digestive fire is called Medrod (མེ་དྲོད་) in Tibetan and is the basis of all digestive processes, and it is particularly referred to the Digestive Tripa (འཇུ་བར་བྱེད་པའི་མཁྲིས་པ་). Digestive fire helps to maintain health, promotes diligence, energy, healthy complexion and longevity, while also enhancing the transformations of 7 bodily constituents.
The digestive system is composed mainly of stomach, small intestine and colon, and 3 humoral energies of Decomposing Beken (བད་ཀན་མྱག་བྱེད་), Digestive Tripa (འཇུ་བར་བྱེད་པའི་མཁྲིས་པ་) and File-accompanying Wind (མེ་མཉམ་རླུང་). In Tibetan medicine, other organs involved in digestive process are described through analogies. The liver is likened to the wood that fuels a fire, while the gall bladder acts as the spark that ignites and maintains the fire's heat. The spleen and kidneys are responsible for supplying the water necessary to break down food. Meanwhile, the heart and lungs contribute by providing the pleasure and appetite needed for eating.
Strong Medrod will ensure proper digestion and metabolism of nutritional essence. It is the main factor responsible for development of subsequent 7 bodily constituents (ལུས་ཟུངས་བདུན་, Luzung), good complexion and strength. Indigestion in turn, will not facilitate the synthesis of essence and wastes and hence will not develop bodily constituents. Therefore, if Medrod is diligently preserved through adherence to a proper diet and lifestyle, such as partaking light food and observing warm lifestyle, health and longevity will be assured.
The digestive process can be divided into stages of general digestion and specific (metabolism).
GENERAL DIGESTION
This entire process starts in the mouth, and takes place between the stomach, where digestion begins, and the large intestine, where digestion is nearly complete. It functions like a factory, enabling the absorption of essential nutrients and the downward movement of waste products.
The Life-sustaining Wind (སྲོག་གི་རླུང་) is responsible for bringing food down to the stomach, where watery and oily parts of the food and drinks break up and soften all the materials.
Thereafter, the Fire-accompanying Wind (མེ་མཉམ་རླུང་), like a gas, helps the Digestive Tripa (འཇུ་བར་བྱེད་པའི་མཁྲིས་པ་) to increase its heat, and Decomposing Beken (བད་ཀན་མྱག་བྱེད་) breaks down the food completely. The process of digestion is the stomach resembles the boiling of medicinal ingredients in a pot.
Digestive organs with the help of three humors help to absorb the different tastes (six tastes) and nutrients at different stages of digestion.
In the stomach, with the help of Decomposing Beken (བད་ཀན་མྱག་བྱེད་), food having water and earth element, and sweet and salty tastes is broken down into sweet, bubbly nutritional essence. It is then, sent to the liver and becomes blood components and generates Beken energy.
Thereafter, in the duodenum and the rest of the small intestine, food that has fire element and sour taste, with the help of Digestive Tripa (འཇུ་བར་བྱེད་པའི་མཁྲིས་པ་) is digested and transformed into sour nutritional essence. It is then, sent to the liver and becomes blood components and generates Tripa energy.
Finally, the Fire-accompanying Wind (མེ་མཉམ་རླུང་) in the large intestine, digests the food with wind element and bitter, astringent and hot tastes, transforming it into bitter nutritional essence. It is then, absorbed and sent to the liver and also becomes blood components and generates Wind energy.
All the food and drinks are decomposed by Beken, digested by Tripa, and transported by Wind. The resulting nutritional essence (the pure part of ingested food and drink, or nutriment or chyle) is send to the liver through veins called the nine absorbing channels (དྭངས་མ་ལེན་པའི་རྩ་དགུ་), beginning the metabolic cycle of the 7 bodily constituents. The waste products of general digestion are separated in the intestines, where the liquid part is transformed into urine and the solid part into stool.
METABOLISM
Bodily constituents are formed through ingesting the six tastes of the five external elements in the form of food and drinks. Food and drinks then go through the process of digestion with the help of the three humors and form the first bodily constituent called nutritional essence. After the general digestion is completed, the nutritional essence is further matured by Medrod into subtler bodily constituents (ལུས་ཟུངས་).
The 7 bodily constituents are:
- Nutritional essence (དྭངས་མ་)
- Blood (ཁྲག་)
- Flesh (ཤ་)
- Fat (ཚིལ་)
- Bone (རུས་པ་)
- Bone marrow (རྐང་མར)
- Regenerative fluid (ཁུ་བ་)
Nutritional essence (དྭངས་མ་)
The first bodily constituent is called the nutritional essence or Dangma. It is the pure part of ingested food and drinks. It is the result of general digestive process, has three post-digestive tastes (sweet, sour and bitter) and after general digestive process is complete it is send to the liver through veins called the nine absorbing channels. Nutritional essence promotes the growth of other bodily constituents. It’s byproduct becomes mucous of the stomach, intestines and other organs.
Blood (ཁྲག་)
The pure part of nutritional essence becomes blood in the liver. Color-transforming Tripa (མཁྲིས་པ་མདངས་སྒྱུར་) gives blood its red colour. Blood moistens the body and sustains life. It carries warmth, nutrients, fluids and life energy to organs, tissues and cells. The waste products of the blood are channeled to the gall bladder and becomes bile juices. Bile juices are divided into 2 parts. A refined part goes with the blood and becomes a drum that protects the skin, and unrefined part goes to the stomach and duodenum to assist in the digestive processes.
Flesh (ཤ་)
The refined part of the blood becomes flesh or muscles. Flesh covers the internal, external and intermediate parts of the body, forms the organs and maintains body’s strength. It is mainly the earth element and it provides stability and protection. The waste products of the flesh becomes orificial impurities, such as nasal discharge, cerium, eye discharge and tears, saliva and sweat.
Fat (ཚིལ་)
The pure part of the flesh becomes the fat. It maintains the body’s oil system, that lubricates, nourishes and insulates the skin, organs and tissues. It is a water and earth elements and has a cold nature. The waste products of the fat is body oils that nourish the skin and keep it young.
Bones (རུས་པ་)
Bones are the refined product of fat and serve as a framework of the body. They form the body structure and support the base of the body. Bones are of earth element and also a house for the wind. The waste products of the bones are teeth, nails and body hair.
Bone marrow (རྐང་མར)
The refined part of the bone becomes the bone marrow. It nourishes the body, gives strength and provides vital energy for its protection. It has an earth and water element and has a heavy quality. The waste products becomes the internal lubricating oils.
Regenerative fluid (ཁུ་བ་)
Bone marrow transforms its essence into regenerative fluids (Khu-wa, semen and ovum). They give pleasure and keep the body youthful. They are rich in the most subtlest material energy that has the potential to give life. Male Khu-wa has moon nature and therefore is white, cold and heavy. Female Khu-wa ha sun nature and fire energy. Both semen and ovum are considered to be a waste products and their essence is called Dang (མདངས་མཆོག་ the supreme vitality). It is the end product of the chain synthesis of 7 bodily constituents and is the final essence. It is light and luminous energy. Although, it resides in the heart, its energy pervades throughout the body to sustain life and bring vigour and radiance. It supports the stability of mind and give intelligence, awareness, fearlessness and long life. It also gives an aura light to the body.
It takes 6 days for a complete transformation of the bodily constituents from the nutritional essence of the food, that is ingested, until it is converted into Dang. However, certain Chudlens produce Dang within one day.
