Take care of your kidneys before it's too late: what dialysis really replaces (and what it can't)

My dialysis patients only realize how important their kidneys were once they’re sitting in front of the machine, four hours at a time, three times a week. By then they’ve lost something a machine can only partly replace. If you still don’t need dialysis, I want you to understand what those two organs behind your lower ribs are actually doing — because they are not just for making urine, and that misunderstanding is what gets people to the ICU too late.

What your kidneys are actually doing while you’re not paying attention

Your kidneys are not a single-purpose drain. They sit at the crossroads of fluid balance, blood pressure, bone health, red-cell production and acid-base chemistry. When they fail, every one of those systems wobbles at the same time. That’s why dialysis feels so disruptive — it isn’t fixing one thing.

Each day, healthy kidneys quietly handle:

• Filtering waste like creatinine and urea, the chemical residue your metabolism leaves behind.
• Adjusting fluid and electrolytes — water, sodium, potassium, calcium and phosphorus — so your heart and your nervous system keep working.
• Regulating blood pressure through renin, a hormone that fine-tunes vascular tone and fluid volume.
• Telling your bone marrow to make red blood cells via erythropoietin. When kidneys fail, anemia follows.
• Activating vitamin D (calcitriol) so calcium gets absorbed and bones stay strong.
• Keeping blood pH in range, which protects muscle mass and cardiac rhythm.

Lose those functions slowly, over years of uncontrolled blood pressure or diabetes, and you don’t feel a thing — until a routine lab shows a creatinine that has quietly doubled.

Why dialysis is never a full replacement

Dialysis is one of the great rescues of modern medicine. It pulls toxins out of the blood, removes excess fluid, and buys time. But it does not produce erythropoietin. It does not activate vitamin D. It does not adjust minute-to-minute to a long run or a salty meal. It is a partial replacement on a fixed schedule for an organ that worked 86,400 seconds a day.

That’s why dialysis patients usually need erythropoietin injections for the anemia, vitamin D analogues for the bones, phosphate binders with every meal, and strict fluid limits between sessions. The machine cleans the blood. The hormones, the metabolic regulation, the constant adjustment — those are gone.

No machine reproduces every hormonal and regulatory job a healthy kidney does. Prevention is far easier than replacement.

This is why ICU admissions in advanced kidney disease are so hard. A patient who comes in with sepsis, or a pneumonia, or a gastrointestinal bleed, no longer has the metabolic buffer most people have. Small problems become organ failures faster.

The risk profile most people ignore

The same handful of conditions destroy kidneys around the world. None of them hurt at the start, which is exactly the point.

• Uncontrolled high blood pressure damages the tiny glomerular filters from the inside.
• Type 2 diabetes changes the structure of the same filters and lets protein escape into the urine.
• Visceral obesity and insulin resistance create the metabolic background where both of the above accelerate.
• Frequent NSAIDs — ibuprofen, naproxen, diclofenac — taken for years as if they were candy.
• Smoking and chronic high alcohol intake, both vascular toxins.

If you check any two of those boxes and your last basic lab is more than a year old, you’re flying blind. A simple panel — creatinine, estimated GFR, and a urine albumin/creatinine ratio — is enough to see the first whisper of damage long before the foam in the toilet, long before the swelling, long before the fatigue.

What you can actually do this month

Kidney protection is not a heroic act; it is a quiet routine.

1. Control your blood pressure for real. Not just the day of the appointment. A home cuff, seven days, twice a day, arm supported. If you’re unsure how, read this guide on measuring blood pressure at home.
2. Keep your salt intake around 5 g a day — about a level teaspoon, total, from everything you eat. Most of it is already hiding in bread, sauces and processed food.
3. Move your body at least 150 minutes a week. Walking counts. The point is to keep insulin sensitivity, blood pressure and weight in a livable range.
4. Hydrate to your context, not to some viral number. Hot weather, exercise and certain medications change the math.
5. Get a full metabolic and renal panel once a year if you’re hypertensive, diabetic, over 50, or have a family history of kidney disease.

If you already carry one of those diagnoses, our Real ICU cases pillar walks through the patterns I see when prevention was skipped — and what that looks like from inside the unit.

Where the academy fits in

If you want to translate the lab numbers into daily decisions, the course on diabetes care explains how to read your own glucose profile, what to eat after a fasting glucose above 100 mg/dL, and how to avoid the metabolic path that ends in kidney damage. It’s the same playbook I use with my own outpatient family.

Further reading

• The National Kidney Foundation keeps an accessible library on early detection, blood-pressure goals and protein-in-urine testing.
• Mayo Clinic describes the clinical course of chronic kidney disease and the lab values that change first.
• The World Health Organization tracks the global rise of CKD as part of the non-communicable disease burden.

I am Richard Suárez, an intensive care physician. If you want to keep learning what I see each week in the unit, and what you can do in your own kitchen and bathroom to stay out of it, subscribe to my YouTube channel. A big hug.