The kidneys are considered to be the root of life in Chinese Medicine and is represented by the water element, it is the last of the five major organs (barring the pericardium) we have discussed and is fundamental in many of the processes of homeostasis that keep us functioning.
Part of the reason the kidneys are considered the root of life is that all other organs rely on some kidney qi to function. For example liver yin which is linked to blood, cannot be made without kidney yin and spleen yang which helps digestion requires kidney yang to prevent digestive upset such as diarrhoea.
As always, a short summary of the kidney functions:
1) Stores Essence: the second reason the kidneys are called the root of life is because they store what is known as essence (Jing). Essence is a substance that is obtained from our parents. It is a set supply which is why TCM practitioners advise parents to be at optimal health prior to conception as this is when the substance is determined. Many modern researchers believe the idea of essence is similar to the concept of DNA. Essence is important as it determines our development, our reproduction and our longevity. As mentioned it is a set amount and cannot be replenished however it can be enhanced to get the most out of it. We will discussed the idea of essence further in a future segment.
2) Produces marrow and builds bone: the kidneys are believed to create marrow and send it to be stored in the brain. From the marrow produced, bones are made. As such it is a different concept to bone marrow in biomedicine though interestingly the kidneys still assist with the production of blood via the essence.
3) Control water: as the kidneys are associated with the water element, it naturally controls water. This works in several different ways. First the kidney is considered the gate that opens and closes pertaining to urination (there is also the association with the lower burner – a concept to be covered in the future). As discussed with the foundation of the lung, the kidneys receive water from the lung which it warms and sends back up as a fine mist to keep the lungs moist.
The kidney is associated with will power and determination, if these things are lacking there may be a deficiency in the kidney qi. It is affected by fear and shock as emotions and susceptible to cold weather (notice your lower back starts to hurt if your shiver too much in the cold – this is the domain and physical location of the kidneys). There is also the idea of the Ming men which is the gate of life/fire however this is much more complex and not required to understand unless you are practicing Chinese medicine.
As always there are several things that have not been mentioned in this article regarding the kidney however what has been mentioned covers a major key points. Please read into the liver, heart, spleen and lung at your leisure to complete your basic knowledge of TCM.