The primary function of the kidneys is to filter and remove waste products from the body via the blood and then return the clean blood back into the body. Inside each kidney, there are about a million tiny filtration units called nephrons. Each nephron is made up of a very small filter called a glomerulus that is attached to a tubule. As blood passes through the nephron, water and waste products are filtered out. Most of the water is then returned to the blood but other waste products are deposited in the urine for eventual elimination. Kidneys that are compromised due to overload or illness will certainly have reduced function and will not be able to filter waste products as well.
People who have a high protein diet or have gout (a form of arthritis where uric acid is deposited in the joints and tissues causing painful swelling) or who may otherwise suspect an overload should consider using a diuretic. It is also advisable to increase your potassium intake (via supplementation or foods such as bananas and cranberry juice) when using a diuretic. Be sure to note all cautions on the product label.
Kidney stones form when your urine contains more crystal-forming substances — such as calcium, oxalate, and uric acid — than the fluid in your urine can dilute. At the same time, your urine may lack substances that prevent crystals from sticking together, creating an ideal environment for kidney stones to form.
Symptoms of kidney stones may include: