Urinary · Renes
Kidneys
They filter your entire blood volume about forty times a day and hand almost all of it back.
- Filtrate per day
- ~180 L
- Returned to you
- >99%
- Nephrons
- ~1 million per kidney
- Blood flow
- ~20% of cardiac output
What it does
Filter waste, balance water and electrolytes, regulate blood pressure, activate vitamin D, and signal for red blood cell production. Failing kidneys break far more than waste clearance.
The marvel
They process roughly 180 litres of filtrate every day and return over 99% of it. You produce a couple of litres of urine from that. Each kidney holds about a million nephrons, and you cannot grow new ones, which is why kidney damage is largely a one-way door.
How to serve it well
Blood pressure and blood sugar
Diabetes and hypertension cause the large majority of chronic kidney disease. Controlling them is the intervention.
Go easy on regular NSAIDs
Frequent long-term ibuprofen and similar drugs can reduce kidney function, particularly with dehydration or existing kidney disease.
Drink to thirst, not to a target
Adequate hydration reduces kidney stone recurrence. Beyond that, more water does not "flush" the kidneys into working better.
Ask for the numbers
Early kidney disease is silent. eGFR and urine albumin are simple tests, and worth requesting if you have diabetes, hypertension, or family history.
Book an appointment
- Foamy urine, or blood in the urine
- Swelling in the ankles, feet, or around the eyes
- Persistent fatigue with reduced appetite
- Needing to urinate much more often at night
Emergency, go now
- Producing very little or no urine
- Severe one-sided flank pain, especially with fever or vomiting
- Confusion or drowsiness with known kidney disease
What you may have been told
“Kidney cleanses and juice protocols detoxify your kidneys.”
Filtration is the kidney doing its job continuously; it does not need help. Some cleanse regimens are high in oxalate, which increases stone risk, and excessive water intake can dangerously dilute blood sodium.
Where this comes from
- National Institute of Diabetes and Digestive and Kidney Diseases · Chronic kidney disease
- KDIGO · Clinical practice guidelines
- NHS · Kidney infection and kidney stones
LUMEN is education, not medical advice, and it cannot know anything about you. It does not diagnose. If something here matches what you are experiencing, take it to a clinician who can examine you.