Kidney stones are described as one of the most painful medical conditions one can have. Kidney stones are caused by oxalate, which is commonly found in humans and plants. Oxalate is not necessarily required by the body, and too much of it can result in kidney stones.
In plants, oxalate helps remove excess calcium, hence their high oxalate content. For humans, oxalate may work as a “prebiotic”, meaning it contributes to good bacteria within the gut.
When oxalate is ingested with the food, it gets broken down by the digestive system and released through our stool or urine. On its way through the intestines, oxalate can bind with calcium and get excreted through our stool. But when high levels of oxalate continuously pass through the kidneys, this is when kidney stones can develop. Calcium oxalate kidney stones are the most common kidney stone variety.
As mentioned, some food items, mainly plant-based, contain high levels of oxalate. Here are the most common foods that contain oxalate along with their oxalate levels.
|Food Item||Serving (oz)||Oxalate Content (mg)|
|Beet greens, cooked||1/2 cup||916|
|Rhubarb, stewed, no sugar||1/2 cup||860|
|Spinach, cooked||1/2 cup||750|
|Chard, Swiss, leaves cooked||1/2 cup||660|
|Rhubarb, canned||1/2 cup||600|
|Spinach, frozen||1/2 cup||600|
|Poke greens, cooked||1/2 cup||476|
|Dandelion greens, cooked||1/2 cup||246|
|Kale, cooked||1/2 cup||125|
|Turnip greens, cooked||1/2 cup||110|
|Collard greens, cooked||1/2 cup||74|
|Broccoli, cooked||1 large stalk||6|
In order to best prevent kidney stones, it’s essential to consume a low-oxalate diet. Here is a chart that outlines the food and beverages to avoid, limit, and consume on a low-oxalate diet.
|Foods to avoid
|Foods to minimize
|Foods to eat
|Dark or “robust” beer
Juice made from high oxalate fruits
Cereal (bran or high fiber)
Crisp bread (rye or wheat)
Whole wheat bread
Whole wheat flour
Beans (baked, green, dried, kidney)
Peppers (chili and green)
Potatoes (baked, boiled, fried)
Black pepper (more than 1 tsp.)
Guinness draft beer
Black currant tea
Purple and Damson plums
Ravioli (no sauce)
Spaghetti in red sauce
Cinnamon pop tart
Potato chips (less than 3.5 oz.)
Cherries (bing and sour)
Grapes (green and red)
Green and yellow plums
Raisins (1/4 cup)
Fish (except sardines)
Cereals (corn or rice)
Chicken noodle soup
Imitation vanilla extract
Jelly made from low oxalate fruits
Ketchup (1 tbsp.)
Aside from eating a low-oxalate diet, there are other measures you can take in order to reduce your risk of kidney stones. Here are some healthy eating guidelines in order to prevent kidney stones.
Drinking enough water is a great prevention method and can make passing of kidney stones easier, so ensure you are getting enough. For many of us, it’s difficult to get the proper amount of water, but these tricks can help you increase your hydration levels:
These tips can help you consume more water throughout the day, which will not only help prevent kidney stones but can improve overall health as well.