Kidneys: How They Work and Why They Matter in Grand Rapids, MI

Your kidneys are vital organs that quietly keep you healthy every day. For people living in Grand Rapids, Michigan—where cold winters, changing seasons, and chronic conditions like high blood pressure and diabetes are common—understanding kidney health is especially important.

What Do the Kidneys Do?

Most people have two kidneys, one on each side of the spine under the lower ribs. They are bean-shaped, reddish-brown, and about the size of a clenched fist.

The kidneys’ main job is to:

  • Filter waste products and extra fluid from your blood
  • Return cleaned blood back to your body
  • Make urine to remove waste from the body

Each minute, about one liter of blood—around one-fifth of all the blood pumped by your heart—flows into the kidneys through the renal arteries.

How Blood Is Cleaned by the Kidneys

After the blood is filtered, it flows back into the body through the renal veins.

Each kidney contains about one million tiny filtering units called nephrons. Every nephron has:

  • A very small filter called a glomerulus
  • A small tube called a tubule

As blood passes through the nephron:

  1. Fluid and waste products are filtered out of the blood.
  2. Most of the fluid and important substances (like salts and nutrients) are returned to the blood.
  3. The remaining waste and extra fluid become urine.

Urine then:

  • Flows from the kidneys through tubes called ureters
  • Collects in the bladder
  • Leaves the body through a tube called the urethra

A healthy kidney usually makes about 1–2 liters of urine each day. This amount can change based on:

  • Your body size
  • How much you drink
  • The temperature (for example, hot and humid summers in Grand Rapids vs. cold winters)
  • How active you are

How Much Can Kidneys Do?

Healthy kidneys have a large “reserve capacity.”

  • With two healthy kidneys, each one does about 50% of the total work.
  • If one kidney is lost or damaged, the other kidney can enlarge and do up to about 75% of normal kidney function (equal to one and a half normally functioning kidneys).

This is why some people can live a healthy life with just one kidney, but it also means protecting your remaining kidney becomes very important.

Other Important Kidney Functions

Your kidneys do much more than filter waste. They also:

  • Help control blood pressure by regulating fluid and certain hormones
  • Help control red blood cell production by making a hormone called erythropoietin
  • Help maintain strong bones by regulating calcium and vitamin D
  • Keep body fluids at the right levels so your organs work properly
  • Regulate body chemistry by balancing salt, water, and other minerals in your blood

For Grand Rapids residents, where high blood pressure and diabetes are common chronic conditions, these kidney functions play a major role in long-term health.

Measuring How Well Your Kidneys Work

It is difficult to calculate exactly how fast your kidneys are working, so doctors use tests to estimate kidney function.

What Is GFR and eGFR?

The glomerular filtration rate (GFR) is the best measure of kidney function. It shows how much blood your kidneys filter each minute.

Because directly measuring GFR is complex, doctors usually use an estimated GFR (eGFR). This is calculated using:

  • The level of creatinine in your blood
  • Your age
  • Your sex
  • Sometimes your race, depending on the equation used

The higher your GFR, the better your kidneys are working.

Typical values:

  • GFR ~100 mL/min/1.73 m² – about equal to “100% kidney function”
  • GFR ~50 mL/min/1.73 m² – about “50% kidney function”
  • GFR ~30 mL/min/1.73 m² – about “30% kidney function”

Blood and Urine Tests for Kidney Health

If your doctor in Grand Rapids (for example at Spectrum Health, Trinity Health Grand Rapids, Metro Health, or Mercy Health) orders blood work to check your kidneys:

  • An eGFR result is usually reported automatically with your creatinine level.
  • Your doctor may also order urine and blood tests to look for signs of chronic kidney disease (CKD), such as:
    • Protein in your urine (albuminuria or proteinuria)
    • Blood in your urine (hematuria)
    • High blood pressure
    • Diabetes or poor blood sugar control

Well-functioning kidneys are essential to your overall health, especially in a climate like West Michigan’s, where dehydration in summer and circulation issues in winter can both affect kidney function.

Who Is at Higher Risk for Kidney Disease in Grand Rapids?

You may be at increased risk of chronic kidney disease if you:

  • Have diabetes
  • Have high blood pressure
  • Have a family history of kidney disease
  • Are over age 60
  • Are overweight or obese
  • Smoke
  • Have heart disease or vascular disease

In the Grand Rapids and Kent County area, these conditions are common, so regular kidney checks are important for many adults.

Keeping Your Kidneys Healthy

Early detection of kidney disease can be life-saving. In many cases, medication and lifestyle changes, along with early referral to a kidney specialist (nephrologist), can prevent or delay kidney failure.

Steps to Protect Your Kidneys

  • Control blood pressure

    • Take medications as prescribed
    • Limit salt (sodium) intake
    • Check your blood pressure regularly

  • Manage diabetes

    • Keep blood sugar within your target range
    • Follow your diabetes care plan

  • Stay hydrated appropriately

    • Drink enough fluids, especially during hot, humid West Michigan summers
    • Ask your doctor how much fluid is right for you if you already have kidney disease

  • Maintain a healthy weight

    • Eat a balanced diet rich in fruits, vegetables, whole grains, and lean proteins
    • Be active year-round (indoor options can help during snowy Grand Rapids winters)

  • Avoid smoking and limit alcohol

  • Use medications safely

    • Avoid overuse of pain relievers like ibuprofen or naproxen unless approved by your doctor
    • Tell your doctor about all prescription and over-the-counter medicines and supplements

  • Get regular checkups

    • Ask your primary care provider for regular kidney health checks, especially if you have diabetes, high blood pressure, or a family history of kidney disease.

Local Kidney Health Resources in Grand Rapids, MI

If you live in the Grand Rapids area and are concerned about your kidney health, you can:

  • See your primary care provider (GP/doctor)

    • Spectrum Health primary care
    • Trinity Health Grand Rapids clinics
    • Metro Health �� University of Michigan Health
    • Mercy Health physician offices

  • Contact local public health services

    • Kent County Health Department – offers information on chronic disease prevention, blood pressure, and diabetes programs
    • Grand Rapids Public Health resources – may provide screenings and community health education

  • Ask for a referral to a kidney specialist (nephrologist)

    • Available through major health systems in Grand Rapids for evaluation and ongoing management of kidney disease

If you are at increased risk of chronic kidney disease, or have diabetes or high blood pressure, talk with your Grand Rapids healthcare provider about:

  • Getting an eGFR blood test
  • A urine test for protein
  • Regular blood pressure checks

Protecting your kidneys today can help you stay active and healthy through every season in West Michigan.