There has been an increased focus on oxalic acid, which is found in many fruits and vegetables. It is especially prevalent in green leafy vegetables which provide many important nutrients. However, oxalic acid can have bad side effects in some people, and it can be poisonous if you eat it in large quantities.
Oxalic acid is a normal plant compound found in high concentrations in green leafy vegetables. When ingested, oxalic acid combines with calcium and magnesium salts to form oxalates, which are excreted through the urine. Because the compound is eventually excreted, it does not pose any health concerns at all if calcium and magnesium levels in the body are normal.
Oxalic acid can pose a health risk if you lack calcium or magnesium. In such a case, if you consume large quantities of oxalic acid you can develop kidney stones. Kidney stones do not usually pose any serious health risk, but they can cause acute pain; they can be removed through a simple surgical procedure. People with kidney problems or gout should not consume too much oxalic acid.
According to Oxalic Acid Info website, the only food with massive toxic quantities of oxalic acid are the leaves of the rhubarb plant; the fruit itself does not pose any risk.
Juicing Book suggests that people with a history of kidney stones and other kidney disorders should avoid drinking juices of fruits and vegetables that have high oxalic acid content. Juices can contain more oxalic acid than the fruit, especially if kept at room temperature for more than 10 minutes.
Oxalic Acid Content
The Nutrient Data Laboratory has listed the oxalic acid content of many fruits and vegetables. Anything over a gram per hundred grams of the fruit or vegetable is considered a high dose of oxalic acid; this level exists in amaranth, chives, parsley and purslane.