Urologist Questions Kidney Stones

Why should people with kidney stones avoid spinach?

My son is 18 years old and has been diagnosed with kidney stones. The doctor has advised him to avoid vegetables like spinach. Is there a specific reason?

7 Answers

The most common form of kidney stones is calcium oxalate. Spinach has a relatively high oxalate content and may predispose some people to kidney stones. Drinking lots of clear fluids such as water is very important as well.
Most kidney stones are made of calcium especially calcium oxalate. Spinach may increase the oxalate excretion in the urine. This among other dietary factors and may cause a higher incidence of recurrent stones
Because of his young age further evaluation including the results of his stone analysis and a metabolic evaluation with a 24 hour urine should be done to evaluate the need for further dietary changes and treatment
Spinach is high in oxalate but everything is fine in moderation and high water intake.
In the United States, the most common type of kidney stone is made from calcium oxalate. Spinach is very high in oxalates, as well as some other related leafy green vegetables such as Swiss chard or kale. You can eat the spinach in moderation, but there are better ways to prevent the stones, starting with hydration, and some forms of medication. This is a good question to discuss with your urologist.
Spinach, other greens, leafy vegetables, along with coffee, tea, dark sodas, and nuts, all have high counts of oxalates in them. For that matter, other foods in excess like meat or protein can cause different types of stones.

Roscoe S. Nelson, MD
Spinach is high in oxalate. Oxalate is a known stone producer. If your son is making calcium oxalate stones, it would be better to stay on a low-oxalate diet.

Hi, spinach is high in "oxalate" which is a component of some - but not all - kidney stones. The doctor probably analyzed a stone or stone fragment to see what its composition was. That information forms the basis of dietary advice.