Wednesday, November 30, 2011

The Kidneys in Chinese Medicine: Physiology & Symbolism

Winter is the time when the energy of the Kidneys predominates. The Kidneys not only govern fluid filtration and urination, but, in Chinese Medicine philosophy, are considered the root and foundation of the body's energy. The health of our Kidneys determines our overall health, the health of our bones, our reproductive capacity, and the grace with which we age. They are responsible for our enduring strength, stamina, and clarity of mind over the long-haul.

Moreover, Kidneys are said to hold our connection to our ancestors. They also relate profoundly to our offspring as they hold the basic material for reproduction and fetal development.

For the sake of good health and longevity, nourishing the Kidneys is of paramount importance. Pregnant women and families thinking of becoming pregnant should be especially mindful of Kidney health.

Hormonal imbalances, conditions related to physical or cognitive development, conditions related to the bones, and issues of aging are all considered to be related to weakness of Kidney energy.

Kidney energy is most available in wintertime. It is vulnerable to being weakened if we don't eat well, rest sufficiently and protect ourselves from the colder weather. On the other hand, winter is the optimal time of the year for nourishing and supporting Kidney health. Please see my related articles for tips on how to do this:

Six Lifestyle Tips for Winter Health

Kidneys as the Foundation of Yin and Yang:

The Kidneys are the foundation of the Yin and Yang of all other organs in the body. Kidney Yin is the fundamental substance for birth, growth and reproduction. It provides the material foundation of the body. Kidney Yang, by contrast, is the motive force of all physiological processes in the body (i.e. digestion, fluid metabolism, respiration, etc.)

Among the precious substances that make up our body are Qi, Blood and Body Fluids. Of these, Qi relates to Yang; Blood and fluids relate to Yin. As the root of Yin and Yang in the body, Kidneys provide the foundation for all body substances and for the organs that produce, move and metabolize these substances. So, we see that Kidneys are truly the foundation of the material substance and the motivating energy of the body. In a related statement, Kidneys are said to be the origin of both Water and Fire in the body.

Kidneys Store Essence and Relate to Ancestry and Reproduction:

In addition to being the foundation of Yin and Yang, Kidneys are said to store Essence (or, in Chinese, Jing). Jing, like Qi and Blood, is one of the precious substances of the body. The Kidneys store two types of Jing: pre-Heaven and post-Heaven.

Pre-Heaven Jing is the inherited Essence (genetic material) from our ancestors that, before birth, nourishes the fetus and after birth controls growth, sexual maturation, fertility and development. This Essence determines our basic constitution, strength and vitality. Post-Heaven Jing is the refined essence extracted from food through digestion. We can tonify our post-heaven Jing through healthy, relaxed lifestyle, and by eating nourishing foods. However, our pre-heaven Jing is our inheritance, or our genetic programming or fate, so to speak, from our ancestors. It can not be changed.

Other Anatomical and Physiological Functions of the Kidneys:

Kidney Essence (or Jing) is the organic foundation of Marrow, which is said to generate the spinal cord and fill the brain. If Kidney Essence is strong, it will nourish the brain, memory, concentration, thinking and sight. If the brain is not adequately nourished by Kidney Essence, there may be poor memory, concentration, dizziness, dull thinking and poor sight.

Practitioners of Chinese medicine will seek to bolster the Kidney function in patients with cognitive or developmental delays.

The Kidney's Marrow is also the basis for the formation of bone marrow. Strong Kidney Essence is critical to healthy development of bones and teeth. Osteoporosis and loss of teeth in old age is related to decline of Kidney Essence.

In Chinese Medicine theory, the Kidneys play an important role in breathing, along with the Lungs. The Kidneys are said to 'hold' down the Qi inhaled by the Lungs. Thus, Kidneys are partly responsible for inhalation, while the Lungs alone are responsible for exhalation. Weak Kidney energy can be a factor in chronic asthma cases.

As already mentioned, Kidneys play a critical role in reproduction. Not only do Kidneys store the Essence which nourishes the fetus and controls growth and development. This Essence is also the basis of semen and menstrual blood. Kidney Yang generates the fire that motivates fertility, sexual desire and sexual function. It warms the uterus to enable it to hold and nourish an implanted fetus. Again, couples hoping to become pregnant are advised to pay attention to their Kidney health, and seek the help of an acupuncturist if needed.

Obviously, the Kidneys are related to water metabolism since they govern fluid filtration and urination. Kidney weakness might be a factor in edema, hypertension or, conversely, in conditions of dryness. In children with chronic bedwetting tendencies, Kidney weakness might be a factor.

The Kidneys are said to open into the ears and manifest in the hair. Decline in hearing and thinning or graying of hair relate to the decline of Kidneys with age.

Kidney weakness is often related to weakness and achiness in the low back, knees and feet. This is because of the Kidney's relationship with the bones, and because the meridians of the Kidney's paired organ, the Urinary Bladder, run through these areas.

Mental-Emotional Aspect of the Kidneys in Chinese Medicine:

In Chinese Medicine, each of the five major organs is said to be connected with an aspect of human spirit. The Kidneys are said to house will-power (translated variously as Yi or Zhi). A person with strong Kidneys has strong will-power and is able to focus on and accomplish goals. This person will be disciplined and skilled. Lack of such will-power or motivation is often an aspect of mental depression. Acupuncturists may tonify a patient's Kidneys in the treatment of depression.

Pathologies of the Kidneys:

Pathologies related to the Kidneys are as varied as the Kidneys' roles and functions. As Kidneys are the foundation of Yin and Yang in the body, both extreme exhaustion and, conversely, an inability to slow down, relax and rest relate to a weakness or imbalances of Kidney energies. As the Kidneys relate to development and maturation, many conditions of old age, or delays/abnormalities in physical or cognitive development, relate to Kidney weakness.

When working with Kidney energy, an acupuncturist often needs to consider the relative balance of Kidney Yin and Yang, since both of these places such a fundamental role in the body's physiology.

Symptoms of a weakness of Kidney Yin include: restlessness, hypervigilence, excessively speedy metabolism, insomnia, feeling of heat, dizziness, tinnitus, vertigo, poor memory, poor hearing, night sweating, hot flashes, dry mouth and throat at night, lower backache, ache in the bones, infertility, depression, slight anxiety.

Symptoms of Kidney Yang weakness might include: lethargy, coldness, slow metabolism, softening of bones, weakness of knees and legs, poor memory, loose teeth, loss of hair or premature graying, weak sexual function, low back ache, infertility, absentmindedness, decreased mental sharpness, edema, urinary and prostate problems, excessive fear and insecurity, bags or dark circles under the eyes, etc.

Issues perceived as hormonal imbalances in western medicine are often related to imbalance of Kidney energy. An acupuncturist is likely to treat the Kidneys in conditions such as "adrenal fatigue," diabetes, thyroid conditions, etc.

Finally, because the Kidneys provide fundamental energies of Yin and Yang to the other organs of the body, Kidney imbalances are often a factor in innumerable pathologies of other organs, such as Heart, Liver, Lungs or Spleen, especially when these conditions are chronic and related to old age.

Symbolic Associations of the Kidneys:

The Kidneys are associated with Water in Chinese Medicine. On a superficial level this is obvious, as a principle function of the Kidneys is metabolism and excretion of body fluids. Beyond that, water constitutes the largest portion of all living matter. Water is the basis of life, just as the Kidneys are the foundation for all material and physiological function in our bodies. Symbolically, water is the most yin of substances, yielding, receptive, cold, deep, dark, and sinking. In the ocean or a rushing river, these yin qualities can be dangerously powerful.

The Kidneys are associated with the season Winter. This is the most yin time of the year—cold and dark. Growth and development are slowed. It is time for resting and reflecting. It is truly the end of the cycle before the return of light and the warmth of spring. (Many of our winter festivals and rituals—Hannukah, Christmas, Yule-- acknowledge this powerful image of the return of light amidst deep darkness. In the somewhat paradoxical statement, Kidneys are the source of both fire and water in the body. Similarly, even in the depth of winter, we celebrate the return of warmth and light.)

As the end of the cycle, winter holds an important connection to the end of life. It is said that the ancestors are close at hand at this time of year. Winter is also the most common, and possibly the most comfortable, time for people to pass into the realm of death. The emotion associated with winter and the Kidneys is commonly thought to be fear in Chinese Medicine philosophy. Fear is perhaps the most pervasive and deepest of our negative human emotions. It is deeper than, say, anxiety or worry. It is related to survival and to the continuity of life and legacy of our ancestors. Fear is countered by hope, love and joy. By embracing hope, love and joy, we promote life and honor our ancestors. Again, our winter rituals and gatherings help to summon up these qualities during the dark season, reminding us of the return of light in spring.

One teacher of mine characterized winter's emotional quality as realistic acceptance or cautious caring, as opposed to fear. This relates to the nature of winter as the end of the cycle and implies a sort of inherent wisdom.

In the human body, the Kidneys are associated with the ears and with the bones. Symbolically, ears correspond with the receptive, reflective, yin quality of winter. Bones relate to the deep, inward quality of winter.

What can we conclude from this constellation of associations with wintertime and the Kidneys? By nourishing our Kidneys we promote our health and longevity. We also honor our ancestors and provide the best chances for our children. We should do this throughout the year, but especially in winter when the energy of our Kidneys is most available. We can do this by resting and reflecting deeply before, eating warm delicious nourishing foods, and pausing to spend time with friends and family in the darkest days before the next yearly cycle begins.

See related articles:
Six Lifestyle Tips for Winter Health

Winter blessings!


Macciocia, Giovanni. The Foundations of Chinese Medicine: A Comprehensive Text for Acupuncturists and Herbalists.

Lectures by Liu Ming, Oakland, CA 2003-2011.

Bliss, Nishanga, Real Food All Year: Eating Seasonal and Whole Foods for Optimal Health and All-Day Energy.

Pitchford, Paul. Healing with Whole Foods: Asian Traditions and Modern Nutrition.

Haas, Elson M., M.D. Staying Healthy with the Seasons.