Kidney Stones

A kidney stone, or nephrolithiasis, is a hard, crystalline mineral material formed within the kidney or urinary tract. Kidney stones form when there is a decrease in urine volume, and/or an excess of stone-forming substances in the urine. Dehydration is a major risk factor for kidney stone formation. They can be extremely painful and cause blood in the urine (hematuria).¹

Impact of coffee on kidney stones

• Usually believed that coffee and caffeinated beverages are bad for kidney stones
• Caffeine is a diuretic and so can cause dehydration (risk for kidney stones)
• Coffee also contains oxalate
• New evidence shows there is far less oxalate in coffee than previously thought
• Caffeine actually affects a hormone in the kidneys that leads to urine being more dilute, decreasing risk of kidney stone formation
• An 8oz cup of coffee per day can decrease risk of kidney stones by around 10%

It is usually believed that drinking coffee and other caffeinated beverages are bad for kidney stones. The thinking behind this is, firstly, caffeine is a diuretic, and so can cause dehydration, which is a risk factor for kidney stones, and secondly, coffee contains oxalate, which is thought to be a risk factor in kidney stones. However, it has been found that there is far less oxalate in coffee than previously thought. New evidence also shows that caffeine affects a hormone in the kidneys (antidiuretic hormone) in a way that leads to the production of more dilute urine, thereby reducing the risk of kidney stones. In fact, the data suggests that a single 8oz cup of coffee per day can reduce the risk of kidney stones by 10%. Just be careful to stay hydrated when drinking coffee, because dehydration still is a major risk factor of kidney stones.²

Sources

              ¹ MedicineNet - Kidney Stones: Pain, Symptoms and Treatment Facts

            ² KidneyStones.org - Treatment Options: Dietary - Fluid Intake