Kidney stones are hard, stone-like masses that can form in one or both kidneys. Also known as nephrolithiasis, urolithiasis or renal calculi. They vary in size from as small as a grain of sand to as large as a golf ball. Kidney stones typically leave the body in the urine stream; if they grow relatively large before passing, their jagged crystalline shape can cause severe pain in the ureters and urethra.

Kidney stones form when the salts and minerals that are normally found in the urine become out of balance. Different kinds of kidney stones are formed from salts in the urine. Consumption of too much calcium can aggravate the development of kidney stones, since the most common type of stone is calcium oxalate.

Symptoms:

Diet:

Reduce your intake of sugar, refined foods, animal products (meats and dairy), caffeine, alcohol, soda, and salt.
Drink more water and eat more fiber, vegetables, whole grains, and vegetable proteins.
Cut down on oxalate-containing foods such as spinach, rhubarb, beets, nuts, chocolate, black tea, wheat bran, strawberries, and beans.

Prevention:

To help prevent any type of stone, fluid intake should be two to three litres per day - water is best.

People who get calcium stones should cut down on foods that have high levels of calcium (dairy products and leafy green vegetables), and oxalate (chocolate, tea, rhubarb, cooked spinach and asparagus). It's important to discuss dietary changes with a doctor – not everyone finds them helpful.

People who get uric acid stones should eat less meat, fish and poultry. Also to help prevent uric acid stones, medicine may be prescribed to control the level of uric acid in the urine.

People who get struvite or "infection" stones need to keep the urine free of bacteria that can cause infection. This may mean taking long-term antibiotics.

Advice:

Drinking lots of water (two and a half to three litres per day) and staying physically active are often enough to move a stone out of the body. However, if there is infection, blockage, or a risk of kidney damage, a stone should always be removed.