March 2018

Battling kidney stones? Use these natural medicines cautiously

Some natural medicines contain oxalate. If too much oxalate builds up in the urine, kidney stones may form in some people. For this reason, taking natural medicines that contain large amounts of oxalate might be a problem for people at risk for kidney stones. Consuming high amounts of vitamin C can also increase the amount of oxalate in the urine. Therefore, natural medicines with high vitamin C content should be used in moderation in people at risk for kidney stones. Here are a few natural medicines to keep an eye out for...

Soy: Highly processed soy foods such as soymilk and soy sauce usually contain lower amounts of oxalates. But soy foods with less processing like soy flour and tempeh contain higher amounts of oxalates and should be used in moderation in people with a history of kidney stones.

Cranberry: Cranberry juice and cranberry extracts also contain a large amount of oxalate. There is some evidence that some cranberry extract tablets can boost the level of oxalate in the urine by as much as 43%. To be on the safe side, people with a history of kidney stones should avoid taking cranberry extract products or drinking a lot of cranberry juice.

Other oxalate containing supplements include sorrel, quillaia, black haw, skunk cabbage, water dock, and rhubarb.

Acerola: Acerola contains a lot of vitamin C. In large doses, it might cause kidney stones in some people.

Rose hip also has high vitamin C content.

Keep in mind that oxalate and vitamin C intake are not the only risk factors for kidney stones. Fluid intake, salt intake, and certain medical conditions can also affect the risk. But avoiding high oxalate-containing supplements and taking vitamin C only in moderation might help.

Reviewed February 2023

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