28/10/2026
KIDNEYS & BONES:THE CONNECTION
The kidneys and bones are closely connected, mainly through how the body controls calcium, phosphate, and vitamin D. When one system is affected, the other often is too.
How the kidneys support bone health
1. Vitamin D activation
Your kidneys convert inactive vitamin D into its active form (calcitriol).
Active vitamin D helps your gut absorb calcium.
Calcium is essential for strong bones
If kidneys don’t work well → less active vitamin D → weaker bones.
2. Calcium balance.
Kidneys help regulate calcium levels in the blood.
Keep calcium at a stable level.
Prevent too much calcium loss in urine.
Kidney problems can lead to low calcium levels, affecting bone strength.
3. Phosphate control
Kidneys remove excess phosphate from the body.
Balance between calcium and phosphate is crucial.
Poor kidney function → high phosphate levels.
→ pulls calcium out of bones → bones become weak.
4. Hormone control (Parathyroid hormone – PTH)
When calcium drops, the body releases PTH.
PTH pulls calcium from bones to keep blood levels normal.
In kidney disease → PTH stays high
→ bones lose calcium over time.
What happens when kidneys are damaged?
In conditions like Chronic Kidney Disease:
Low active vitamin D.
High phosphate.
Low calcium.
High PTH.
This leads to bone weakening, known as
Renal Osteodystrophy
Effects on bones:
🔹Weak, brittle bones.
🔹Bone pain.
🔹Higher risk of fractures.
🔹Growth problems (in children).
How to protect both kidneys & bones
▪️Drink enough water.
▪️Control blood pressure & sugar.
▪️Get safe sunlight exposure .
▪️Eat balanced calcium (not excessive).
▪️Limit high-phosphate processed foods.
▪️Avoid overuse of painkillers (NSAIDs).
SIMPLE WAY TO REMEMBER:
👉 Kidneys “activate and balance” → Bones “build and stay strong”.