SPARE PARTS

THe organs we can live without: A spare kidney

OUR kidneys’ functions include filtering the blood to produce urine, making red blood cells and regulating blood pressure.

But we can do fine with just one, says Dr Andrew Goddard, a spokesman for the Royal College of Physicians and consultant physician at the Royal Derby Hospital.

The reason we have two is likely to be due to an evolutionary mechanism to protect our ancestors against severe dehydration.

When the body is deprived of fluids, the brain releases a hormone, vasopressin, which reduces the amount of water the kidneys excrete. Having two do this is better than one.

While most people with one kidney live normal lives, Professor Goddard says that some will have higher blood pressure and one in 200 may have kidney failure, so will need dialysis.