Kidneys, the Blood Filters

by | May 15, 2023 | Resilience

If waste products were to accumulate in your blood, it would cause serious health problems in multiple body systems. That’s where your kidneys come in. 

Pass water. Answer nature’s call. Urinate. Eliminating wastes may not be suitable dinner table conversation, but without a waste removal system the body would not function. That’s a primary function of the kidneys, but this vital organ does much more than that to keep your body in balance, including regulation of blood pressure. In this Insight we’ll talk about the kidney’s most basic functions and what you can do to keep them healthy, so they can help to keep you healthy. 

Food and water provide the nutrients the body needs for energy and maintaining healthy body tissues; the bloodstream transports those nutrients to cells. As with any production of any product, when cells convert the energy in food into a form they can use (see Insight Mitochondria: Your Body’s Energy Factories) waste materials are created, and those are carried away by the blood. As you can imagine, if that waste were to accumulate in your blood, it would cause serious health problems in multiple body systems. That’s where your kidneys come in. 

Kidneys are two fist-sized-bean-shape organs just below the ribcage near the spine. They produce the urine that fills up the bladder, which just holds urine until it’s convenient for you to eliminate it. Kidneys are the actual source of urine, which is simply a blood waste product. 

Filters for the Blood

Adults have about 1.3 gallons of blood in circulation, and it moves from the heart to body tissues and organs back to the heart to the lungs back to the heart and back to the tissues again, and so on. Every ounce of that 1.3 gallons of blood passes through the heart, tissues, organs, and lungs multiple times every day, transporting nutrients and wastes in order to maintain a healthy body.

Blood appears to be red, but when the red blood cells are separated out, you can see that about 60% of the blood is a yellowish watery substance called plasma.

The kidneys remove these and other waste products from blood plasma: 

  • urea and ammonia, generated in the liver
  • creatinine, generated in muscle cells
  • small molecules such as carbon dioxide and salts 

The kidneys also remove 

  • excess water 
  • excess water-soluble nutrients like B vitamins and vitamin C
  • heavy metals such as lead, mercury, arsenic, and cadmium 
  • certain types of toxins

Those are some of the things your kidneys do for you. What can you do for them? Here are three important ways to protect your kidneys: 

  1. Drink enough water. (See News Brief How Much Water Do You Really Need to Drink?) One way to tell if you are getting enough is the color of your urine, which should be a pale yellow. If it is dark yellow, it may mean you need to drink more water. (It’s always a good idea to check with your healthcare provider on such issues.) 
  2. Keep your blood pressure in a healthy range. When blood pressure is too high, it puts a strain on the kidneys’ filtration mechanism.
  3. Keep your blood glucose levels in a healthy range. Many sources, including the Mayo Clinic, note that high levels of blood glucose damage both the blood vessels and the filtering mechanisms in the kidneys.
Fundamentals of Health Alliance

Fundamentals of Health Alliance


The Fundamentals of Health Alliance works to publish useful and reliable information about nutrition and health. Their mission is to empower readers to be informed with honest, non-biased information about food, nutrition and the vital components of health.

Subscribe To Our Newsletter

Join our mailing list to receive the latest news and updates from our team.

You have Successfully Subscribed!