Calcium oxalate stones, the most common type of kidney stone, form when calcium and oxalate (or oxalic acid, which is naturally present in many plant-based foods and is also produced by the body as a waste product) bind together, forming crystals that can accumulate into a hard "stone."
Having excessive calcium in the urine (hypercalciuria) is the most common cause of calcium oxalate kidney stones. Calcium naturally in foods does not cause this (and can actually help), but people prone to calcium oxalate kidney stones are advised to avoid high-dose calcium supplements and to stay well-hydrated (as inadequate fluid intake can increase the risk of kidney stones). Those with high urinary oxalate levels may also be advised to maintain a low-oxalate diet, which typically limits intake to about 50 to 100 mg of oxalate per day.
Interestingly, too little citrate in the urine (hypocitraturia) is also a risk factor for developing calcium oxalate kidney stones.
Sign in as a member to find out which supplements and foods may decrease the risk of calcium oxalate kidney stones, which may increase risk, and which have been promoted to help with kidney stones but have little evidence to support their use. The full answer includes information about calcium and vitamin D supplements, potassium, hydroxycitric acid (HCA), vitamin C, curcumin and turmeric, collagen and chanca piedra, beverages such as beetroot juice, cranberry juice, lemon juice, orange juice, Crystal Light, green tea, coffee (caffeinated or decaffeinated, with or without milk), plant-based milks such as almond milk, and foods such as cocoa and dark chocolate, chia seeds, apple cider vinegar, plant-based "meats," and more, including 30 foods that are highest in oxalates. Also find out how much citrate is in popular kidney stone supplements such as Horbaach Potassium Citrate, MoonStone Stone Stopper and Thorne Potassium Citrate, and how they compare to prescription potassium citrate Urocit-K.