What do the kidneys do?
Body Basics, Education, Toxins, Vitamins and Minerals

What do the kidneys do?

Since we are all slowly becoming experts on the body, I thought that it was only fitting that we have a little lesson about some of my favorite organs, the kidneys. Why are the kidneys one of my favorite organs you might ask? The reason is because they are so unassuming yet so powerful. By strengthening and cleansing the kidneys, I have personally seen some of the best improvements in health so far. So let’s learn all about what the kidneys do!

How could this be? The kidneys are the last stop shop for filtration and cleansing in the body, and without their proper functioning, the body goes awry. And the funny part is, some of our most popular ailments are the result of the kidneys, and we do not even know what they do! So I am here to change that. By the end of this post, I would like you to no longer say… “Ahhh, I have a low backache” but to say “Ahhh, my kidneys hurt!”

What do the kidneys do? What are their function?

The main function of the kidneys is that of forming urine and through that function, the body is able to maintain homeostasis. Homeostasis is the mechanism that keeps the body’s environment stable and constant which is vital to life. Through this process, the blood is able to stay clean and the body can efficiently get rid of waste while maintaing healthy fluid levels and blood pressure levels.

1. Urine Formation

Through the formation of urine, the kidneys are able to one of the most important detoxification organs in the body. The formation of urine involves, filtration, reabsorption and secretion.

Filtration– The kidneys filter water and dissolved substances (sodium, nutrients, glucose) out of the blood.

Reabsorption– Water and dissolved substances are separated from waste products in the urine and then filtered back into the blood system for use.

Secretion– Toxic waste products such as hydrogen ions, potassium ions, and drugs are secreted into the urine for excretion.

Urine Formation

2. Acid/Base (pH) Balance

The kidneys play a primary role in maintaining acid base balance in the body by selecting which ions to retain and which ones to excrete. This allows the body’s total acid burden to be constant, as the urine’s acidity fluctuates to accommodate the balance. If the blood is too acidic, meaning that there is an excess of hydrogen ions, the kidney moves these ions to the urine.

The kidneys help to maintain the blood plasma at a neutral pH 7.4. By regulating the body’s pH, the kidneys help to maintain an environment which prevents diseases from inhabiting the body and promotes the efficient functioning of all bio-systems.

3. Blood Volume and Pressure

The kidneys meticulously adjust the volume and concentration of the urine to accommodate changes in the body, including variations in your daily food and beverage intake. These adjustments on whether to retain or release substances or water, come from ADH (antidiuretic hormone), renin, angiotensin and aldosterone. Therefore, the kidneys are a vital component to maintaining healthy blood pressure levels. 

ADH and Water Retention: When blood volume or pressure falls too low, or when the fluid outside our cells becomes too concentrated, the pituitary gland releases ADH. ADH tells the kidneys to reabsorb water and increase urine concentration. Consequently, if you are dehydrated, the kidneys will excrete less water.

Renin and Sodium Retention: When blood pressure gets too low, an enzyme called renin is released. Renin causes the kidneys to reabsorb sodium, which causes water retention. This restores normal blood pressure and volume.

Angiotensin and Blood Vessel Constriction: Renin also activates angiotensin which is a powerful vasoconstrictor. Meaning it will cause blood vessels to constrict, increasing blood pressure.

Aldosterone and Sodium Retention: When angiotensin is released, it stimulates the release of the hormone aldosterone from the adrenal glands. Aldosterone tells the kidneys to retain more sodium and therefore water, restoring normal blood pressure in the body.


4. Fluid and Electrolyte (salt) Balance

The kidneys control the body’s water content through the “water-retaining hormone” ADH (antidiuretic hormone). If ADH is present, the body decreases the amount of urine formed and therefore less water is lost. If ADH is not present, the amount of urine formed increases, and more water is lost. This is a very delicate balancing act.

The control of electrolytes (salt) is monitored through the hormone Aldosterone (salt and water retaining hormone). If sodium is low, aldosterone stimulates the kidneys to reabsorb sodium, therefore increasing water reabsorption, and decreasing water lost from urine. Therefore, any disfunction in the kidneys can cause symptoms such as water retention and edema.

5. Waste Excretion

The main function of the kidneys is to excrete toxins and waste products that accumulate in the blood. Therefore, the kidneys are a blood cleanser. One of their main jobs is excreting nitrogenous waste products, such as ammonia and urea, which are byproducts of protein breakdown. If the kidneys are not functioning properly, often due to high intakes of animal proteins, their ability to filter out these toxins is greatly reduced. This leads to problems such as gout and kidney stones.


6. Hormone Secretion and Red Blood Cell Production

One very important hormone produced by the kidney is called erythropoietin. It plays a key role in the production of red blood cells in the bone marrow as well as hemoglobin. It also plays a role in smooth muscle fiber proliferation, wound healing and can increase iron absorption.

When the kidney detects that the number of red blood cells in the body is declining, it produces erythropoietin. This hormone is released into the bloodstream and goes to the bone marrow. This triggers the production and release of more red blood cells.


7. Vitamin D Utilization and Bone Health

When the body comes into contact with sunlight, the UVB wavelengths react with 7-dehydrocholesterol, a precursor from cholesterol. This reaction forms the previtamin, Vitamin D3. In order for this previtamin to be utilized as Vitamin D, it must go through two reactions, one with the liver and one with the kidneys. Therefore, it is a vital job of the kidney to maintain healthy vitamin D levels in the body. Once vitamin D is activated by the kidneys, it acts as a hormone, promoting bone growth and maintenance by maintaining blood concentrations of calcium and phosphorus.

Image by monicaswiet


The Kidneys Role in Chinese Medicine

Chinese Medicine tends to have a more holistic view of the body and looks at the body as a whole and its interactions with its environments. Chinese Medicine believe that kidneys are greatly affected by emotions, including fear and unresolved anger. They see the kidney as the “Minister of Power” or the “Root of Life.” Meaning that they are an important reservoir of essential energy. Therefore the question of “what do the kidneys do?” is quite different from this perspective. These viewpoints can be very helpful so here are some perspectives from Chinese Medicine.

  • Image by Ed .

    Peak Energy Times 5-7 am

  • Governs birth, growth, reproduction, development, sexual vitality, and aging
  • Controls willpower- expresses ambition and focus
  • Controls bone, particularly lumbar spine and knees
  • Produces marrow
  • Nourishes brain to sustain concentration, clear thinking and memory
  • Facilitates inspiration
  • Controls teeth, head hair, ears (hearing) and equilibrium
  • A healthy kidney is expressed as gentleness, groundedness, courage, willpower and endurance

Signs of Deficiency:

  • Indecisiveness, fear in pit of stomach
  • Cold feet and legs
  • Abundant swelling, edema
  • Bladder issues
  • Fearfulness, anxiety, antisocial tendencies
  • Chronic fatigue
  • Lack of will, impatience, discouragement, laziness
  • Low sex drive
  • Sciatica, lumbago
  • Inflammation, musculoskeletal irritation

Dreams (when kidneys are weak):

  • One dreams of drowning, swimming after a shipwreck
  • One dreams of being immersed in water
  • One feels like the back and waist are split apart, spine is detached from body

Now that we feel as though we have gotten to know our kidneys a little better, and therefore feel as though we might want to give them a little attention, how about an annual kidney cleanse. Engaging in a kidney cleanse and supplement protocol is going to be the first step in your detoxification process. Since the kidneys are the most delicate, yet more powerful organ, I believe they should always be the first ones to be taken care of. In addition to reducing your overall toxic load from your personal care items, and diet, please take a look at this cleanse to get started.

If you think that your kidneys are good to go, that they are fine just the way they are… I would say that I would not bet on it. Living in the world today, no matter how healthy a lifestyle, guarantees congested and stressed kidneys. A few signs and symptoms include:

  • Loss of Hearing or Ringing in the Ears
  • Social Anxiety, ADD, ADHD
  • Low sex drive
  • Infertility
  • Thin Skin
  • Weak Nails
  • Foggy Head
  • Low Back Pain
  • Low Energy
  • Edema
  • Terrible Balance, clumsiness
  • Feelings of Fear
  • Poor Physical Development
  • Bladder Issues
  • Kidney Stones

Don’t worry, the good thing is that the kidneys are extremely responsive, and there is hope yet! Beginning with the kidney cleanse is a great first step. Check out my book, the Miracle Kidney Cleanse to get started!





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