Kidneys and urine production in Chinese medicine

Su Wen, a theoretical book on the theory of Chinese medicine, says, “The kidneys are the internal organs of water and govern the body fluids.” Two thousand years ago the ancient Chinese already recognised that the kidneys have the function of regulating the metabolism of water in the body.

Absorption of water from food

In Chinese medicine, food is digested in the stomach to form chyme, which is transported to the small intestine. The small intestine divides the chyme into clear and turbid parts.

The clear substances include food essence and essential water, which are absorbed by the small intestine.

The turbid substances consist of food residues and unwanted water. The food residues are transported to the large intestine to form faeces; the unwanted water, through the triple-Jiao channel, seeps into the bladder to form urine.

Transport of water

Water absorbed in the small intestine is transported by the spleen Qi to the internal organs and limbs. Excess water from internal organs after functioning is transported through the triple-Jiao channel to the bladder to form urine.

A part of the water transported to the lungs is spread to the head and skin by the raising and dispersing functions of the lung Qi, and becomes the source of sweat. The other part of the water is transported downwards to the kidneys by the purifying and descending functions of the lung Qi and becomes a source of urine.

Transformation of water to urine

The energy that supports the kidneys in performing their functions is called kidney Qi, while kidney Yin and kidney Yang are the two physical natures of the kidneys. Kidney Yang has the functions of warming and propelling, also known as kidney fire, while kidney Yin has the functions of moistening and calming, also known as kidney water.

The process of water forming urine is called the transformation of Qi, and kidney Qi and kidney Yang play a key role. This transformation process can be likened to boiling water with fire. The clear part of the water transpires upwards and is transported to the lungs, where it re-participates in water metabolism; the turbid part becomes urine, which is stored and excreted by the bladder. Kidney Qi has the function of controlling the bladder and regulating the excretion of urine.

Deficiency of kidney Qi may develop into deficiency of kidney Yang in severe cases. In the case of kidney Yang deficiency, water cannot be converted into urine, which can lead to scanty urination and oedema. In the case of kidney Yin deficiency, kidney fire is excessively active, and if the heat caused by Yin deficiency is combined with pathogenic water-dampness, frequent urination can be seen. In addition, if kidney Qi is severely deficient, it may be incapable of controlling the bladder, leading to urinary incontinence.

Syndromes caused by dysfunction of the kidneys in regulating water metabolism

Oedema due to deficiency of kidney Yang

In Chinese medicine, oedema is classified as Yin oedema and Yang oedema. Yang oedema is caused by pathogenic factors and has four types: combination of pathogenic wind and water; combination of sore toxin and dampness; water-dampness; combination of dampness and heat. Yang oedema is mainly related to the lungs and spleen. Yin oedema is mainly caused by fatigue and physical weakness, and Yin oedema is mainly related to the spleen and kidneys.

Oedema caused by deficiency of kidney Yang belongs to Yin oedema, and its symptoms are: oedema is recurrent, face and body are swollen, and worse below the waist, and the skin is sunken without rebounding when pressed; urine volume generally decreases, but it also may increase; lower back is painful and feels cold, and the limbs feel cold; the person fears coldness, feels fatigue, and the face is pale; the person suffers from palpitations, tightness in the chest, and shortness of breath, so that it is difficult to lie down, while abdomen looks large, and feels distended and fullness; tongue is pale in colour, and fat in shape, and tongue fur is white; pulse is sunken and thin, or it is sunken, sluggish, and weak.

The treatment of the syndrome is warming the kidneys for promoting Yang, and activating the transformation of Qi for moving water. The representative recipe for the treatment is Zhen Wu Tang.

Frequent and incomplete urination with dripping down due to tiredness

In the syndrome, the urine is not much yellow or red in colour and there is no much pain during urination, however, the urine is discharged intermittently and often takes a long time, which is especially likely to occur when the person is tired; with sallow face and short breathing, the person is unwilling to speak, and looks tired and weak; the lower abdomen has the feeling of falling and swelling, and there is a sense of tenesmus, or the urine drips down little by little when defecating; the lower back and the knees are aching and weak; the tongue is pale, and the pulse is thin and weak.

The syndrome needs to be differentiated between deficiency of kidney Yang and deficiency of kidney Yin. In the case of kidney Yang deficiency, the person fears coldness and the limbs feel cold; in the case of kidney Yin deficiency, the face is flushed, the palms of the hands, the soles of the feet and the region of the heart feel hot, and the person feels restless.

The principle of treatment is to invigorate the spleen and kidneys, and the representative recipe is Wu Bi Shan Yao Wan.

Turbid urine due to deficiency of kidneys

In the syndrome, the condition of turbid urine lasts for a long time, and the color of urine is white like milk or lard; with mental depression, the person is emaciated and lacking in strength; with dizziness and tinnitus, the person feels aching and weak in the lower back and knees. In the case of deficiency of kidney Yin, the person feels restless and hot, and the mouth is dry; the tongue is red, and the pulse is thin and rapid. In the case of deficiency of kidney Yang, the face is pale, the body feels cold, and the limbs are cold; the tongue is pale red, and the pulse is sunken and thin.

In case of deficiency of kidney Yin, the treatment is strengthening Yin and nourishing the kidneys with a recipe named Zhi Bai Di Huang Wan. In case of deficiency of kidney Yang, the treatment is warming the kidneys and strengthening the controlling function of kidneys with a recipe named Lu Rong Bu Se Wan.

Difficulty of urination due to deficiency of kidney Yang

In the syndrome, the urine cannot be discharged, or drips down little by little, and there is feeling of weakness when urinating; the person has a pale face, and feels depressed, and the voice is timid and weak; the person fears coldness, the limbs are cold, and the lower back and knees are cold, aching and lacking in strength; the tongue is pale in colour, and fat in shape, and the tongue fur is thin and white, and the pulse is sunken and thin or weak.

The treatment principle is to warm and strengthen kidney Yang, and to activate the transformation of Qi and promote the discharge of water. The representative recipe is Ji Sheng Shen Qi Wan.

published on

updated on

Yike Jiang avatar