When it comes to kidney stone prevention, drinking plenty of fluids is generally recommended. Fluids dilute and increase the volume of the stone-forming substances in urine, which makes them less likely to crystallize (3Trusted Source). However, not all fluids exert this effect equally. For example, a high intake of water is linked to a lower risk of kidney stone formation (7Trusted Source, 8Trusted Source). Beverages like coffee, tea, beer, wine, and orange juice have also been associated with a lower risk (9Trusted Source, 10Trusted Source, 11Trusted Source).
Citric acid is an organic acid found in many fruits and vegetables, particularly citrus fruits. Lemons and limes are especially rich in this plant compound (16Trusted Source).
Citric acid may help prevent calcium oxalate kidney stones in two ways (17Trusted Source):
Preventing stone
formation:
It can bind with calcium in urine, reducing the risk of new stone
formation (18Trusted Source, 19Trusted Source).
Preventing stone
enlargement:
It binds with existing calcium oxalate crystals, preventing them from
getting larger. It can help you pass these crystals before they turn into
larger stones (16Trusted Source, 19Trusted Source).
Oxalate (oxalic acid) is an antinutrient found in many plant foods, including leafy greens, fruits, vegetables, and cocoa (20Trusted Source). Also, your body produces considerable amounts of it. A high oxalate intake may increase oxalate excretion in urine, which can be problematic for people who tend to form calcium oxalate crystals (21Trusted Source). Oxalate can bind calcium and other minerals, forming crystals that can lead to stone formation (21Trusted Source). However, foods high in oxalate also tend to be very healthy, so a strict low-oxalate diet is no longer recommended for all stone-forming individuals.
Studies indicate that vitamin C (ascorbic acid) supplements are associated with a higher risk of getting kidney stones (22Trusted Source, 23Trusted Source, 24Trusted Source). A high intake of supplemental vitamin C may increase the excretion of oxalate in the urine, as some vitamin C can be converted into oxalate within the body (25Trusted Source, 26Trusted Source). One Swedish study among middle-aged and older men estimated that those who supplement with vitamin C may be twice as likely to develop kidney stones as those who don’t supplement with this vitamin (23Trusted Source).
It’s a common misunderstanding that you need to decrease your calcium intake to reduce your risk of forming calcium-containing stones. However, this is not the case. In fact, a diet high in calcium has been associated with a decreased risk of forming kidney stones (28Trusted Source, 29Trusted Source, 30Trusted Source, 31Trusted Source). One study placed men who had previously formed calcium-containing kidney stones on a diet containing 1,200 mg of calcium per day. The diet was also low in animal protein and salt (29Trusted Source). The men had about a 50% lower risk of developing another kidney stone within 5 years than the control group, which followed a low-calcium diet of 400 mg per day.
A diet high in salt is linked to an increased risk of kidney stones in some people (30Trusted Source, 32). A high intake of sodium, a component of table salt, may increase calcium excretion through urine, which is one of the main risk factors for kidney stones (33Trusted Source). That said, some studies in younger adults have failed to find an association (31Trusted Source, 34Trusted Source, 35Trusted Source). Most dietary guidelines recommend that people limit sodium intake to 2,300 mg per day. However, most people consume a lot more than that amount.
