Eating fruits and veggies rich in calcium and potassium may prevent kidney stones

ROCHESTER, Minn. — There’s yet another reason to eat your fruits and veggies. They just might prevent the development of recurring kidney stones. People who have developed a kidney stone are all too aware of how much pain they can cause, with some comparing it to giving birth. Kidney stones also have a connection to chronic kidney disease, osteoporosis, and cardiovascular disease. For those who develop a kidney stone for the first time, the likelihood of a recurrence is 30 percent within five years.

So, is there any good news? According to a Mayo Clinic prospective dietary study, the answer is yes. The results indicate that consuming foods rich in calcium and potassium may avert a second bout with kidney stones.

Researchers compared the results of a questionnaire sent out to 411 patients who developed symptomatic kidney stones for the first time against those of a healthy control group of 384 people visiting one of two Mayo Clinics between 2009 and 2018. Odds of a first-time symptomatic kidney stone, according to the findings, rise in association with reduced fluid intake, low levels of dietary calcium and potassium, and high levels of caffeine and phytate.

1 in 6 developing another kidney stone within 5 years

Of the study participants who developed kidney stones for the first time, 73 ended up with another kidney stone episode within about 4.1 years. When researchers delved deeper, however, they found the common predictive culprit to be dietary. Those consuming lower levels of calcium and potassium were most likely to have kidney stones during the follow-up period.

“These dietary findings may have particular importance because recommendations for preventing kidney stones have been based primarily on dietary factors associated with first-time rather than recurrent stone formation,” says Andrew Rule, M.D., a Mayo Clinic nephrologist and senior author of the study, in a media release. “Patients may not be likely to adjust their diet to prevent an incidence of kidney stones, but they are more likely to do so if it can help prevent recurrence.”

kidney stone diagram
Credit: Mayo Clinic

Not all fluids are good fluids for your kidneys

Even though our fluid intake includes what is in all of our beverages as well as the fruits and vegetables we consume, achieving the recommended daily minimum of about nine 12-ounce glasses sounds daunting. Nevertheless, folks who do not regularly achieve that goal are more likely to develop a kidney stone, especially if they are constantly consuming coffee, soft drinks, or other caffeinated beverages — which leads to low urine volume and increased urine concentration.

If they chase those caffeine-laced drinks down with copious amounts of whole grains and nuts, this can aggravate the problem. Wait, aren’t whole grains and nuts healthy? Yes, but they do contain high levels of phytate — an antioxidant compound that can lead to increased calcium absorption and urinary calcium excretion.

So, where is the good news? Even though fluid intake is important, researchers recommend that instead of tracking fluids, those at risk for recurrent kidney stones focus instead on calcium and potassium-rich food sources, especially in the form of fruits and vegetables.

Which foods should you buy in the produce aisle?

Study authors prescribe 1,200 milligrams of calcium daily to prevent both first-time and recurrent kidney stones. This aligns with the Department of Agriculture’s (USDA) daily recommended nutrition guidelines. While researchers also endorse more potassium consumption, the USDA does not have a recommended daily amount and the authors declined to establish a specific level of recommended potassium.

So, what information should people come away with if they want to prevent a painful kidney stone? That sage advice again: eat more fruits and vegetables, focusing on those that are high in calcium and potassium. Start with your favorite fruits: bananas, oranges, grapefruits, cantaloupes, honeydew melons, kiwis, berries, pineapples, papayas, avocados, and apricots. Add some calcium and potassium-rich vegetables to your next meal: dark green leafy vegetables, potatoes, mushrooms, peas, broccoli, cucumbers, and zucchini.

The findings are published in Mayo Clinic Proceedings.

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Comments

  1. Kidney stone is a kind of painful disease. Every time it occurs, it will make the patient feel overwhelmed. Kidney stone patients should take light food at ordinary times, and they can eat more foods rich in vitamin A. Do not eat spicy and irritating food.

  2. Are not some of those items also high in oxalate for which high oxalate intake can cause kidney stones?

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