Does Being Vegetarian Cause Kidney Stones?

A plant-based diet has numerous health benefits, like reduced risk of heart disease, lower cholesterol and more.

Medically reviewed in January 2019

Are you thinking about becoming a vegetarian to support your good health. Along with eating more vegetables, should you be more concerned about developing kidney stones?

Kidney stones are one of the more uncomfortable afflictions and if the stones block the flow from the kidneys, they can cause serious damage to the kidney itself. So, how are kidney stones and vegetables related?

How do kidney stones relate to a vegetarian diet?
Because most stones are calcium oxalate (about 70% or more) it was once believed that you should restrict foods high in calcium and oxalate to develop fewer kidney stones. Because oxalate is found in vegetables, you should restrict your vegetable intake, right? Turns out it’s not that simple.

  • Not all vegetables contain oxalate
  • If oxalate and calcium levels in a food are balanced, they stay in the gut and do not reach the kidneys
  • Diets high in protein and meat are associated with more kidney stones
  • A variety of other factors including dehydration, excessive vitamin C and excess salt also contribute to kidney stones

Has your urologist told you that vegetarians are prone to developing kidney stones? Was he completely accurate or completely off base? Well, neither or both, depending on how you look at it.

Carnivores get more kidney stones
Oxalate and calcium are more common in certain foods that are found in a vegetarian diet; however, it appears vegetarians get fewer stones than meat eaters.

In a study done in 1979, men with the highest meat consumption were more likely to repeatedly form stones due to an increase in the urinary excretion of calcium, oxalate and uric acid. This study was repeated in 1982 and vegetarians had a 40 to 60 percent decreased risk for developing kidney stones. In another study from 2009, the DASH diet (usually recommended for hypertension) cut the risk for kidney stones almost in half. The DASH diet includes:

  • High intake of fruits, vegetables, nuts and legumes, low-fat dairy products and whole grains
  • Some lean meats
  • Low intake of sodium, sweetened beverages, and red and processed meats

Not all vegetables are created equally
Other studies have looked mostly at how oxalate and calcium leave your body in urine or at the amount of oxalate in the foods. They’ve found certain vegetables and foods with the highest oxalate content, like spinach, rhubarb, Swiss chard, strawberries, nuts, cocoa powder, chocolate, beets, beet greens, peppers, tea (both black and green), okra, peanuts, pecans, wheat germ and bran contain sufficient oxalate to increase excretion in urine. Of those foods mentioned beet greens, rhubarb, chard and tea pose the highest potential risk. If you have a history of kidney stones and your diet is high in these foods, then you are likely at a higher risk for developing more stones. So, what can you do?

Our recommendations:

  • Drink plenty of water (a simple formula to determine your daily water is ½ ounce per pound of body weight; eg; 150 pounds = 75 ounces a day).
  • Consume small amounts of protein (high protein leads to more calcium and oxalate in the urine).
  • Consume only small amounts of sodium (sodium increases urinary excretion of calcium).
  • Avoid the main oxalate-rich, calcium-low foods, such as tea and cocoa.
  • If you must consume high-oxalate foods, mix them with high-calcium foods, like chocolate with a little skim milk (this will keep the calcium and oxalate from reaching your kidneys) or boil high-oxalate leafy greens and discard the water.
  • Avoid vitamin C in high doses (this can be converted to oxalate and come out in the urine).
  • Avoid high-dose calcium supplements taken once a day (these increase calcium excretion in the urine) or if you must take calcium supplements take them in the form of calcium citrate and take smaller doses, two to three times a day with meals.
  • Avoid the standard American diet or diets high in meats.
  • Enjoy other vegetarian foods.
  • If you have a stone, strain your urine and bring it in for analysis (to make sure that you are like most people and have calcium oxalate stones, other stones have other recommendations).
  • If you have calcium oxalate stones, talk to your urologist about taking potassium citrate.

You may want to share this post with your urologist. All good doctors want to give their patients the most accurate information possible but often time does not permit them to do so. This will help them help others who want to follow a vegetarian diet but have a history of kidney stones.

Looking for other ways to live a healthier, happier life? Reverse heart disease and diabetes, lose weight and reduce your cancer risk with these tips from Dean Ornish.

This content originally appeared on Ornish Living.

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