10 Foods that Trigger Kidney Stones

According to the National Health and Nutrition Examination Survey (NHANES), kidney stones affect approximately 1 in 11 people in the U.S.

They are more common in men than women. These stone-like lumps can develop in one or both the kidneys and can cause a great deal of pain.

Kidney stones develop when different types of chemicals in urine, such as uric acid, phosphorous, calcium and oxalic acid, become highly concentrated.

Small stones tend to pass out of the body without causing much problem. Bigger stones cause severe pain, which comes and goes.

Other symptoms include frequent need to urinate, less urination at a time, painful urination, blood in the urine, smelly urine, nausea, vomiting, chills, fever and restlessness.

Factors that increase a person’s risk of developing these stones include a family history of kidney stones, dehydration, being overweight, digestive diseases, urinary tract infections and eating a diet high in protein, sodium and sugar.

People who have had kidney stones in the past also are at a higher risk of the problem recurring.

Diet is a key factor that is easily within your control. Eliminating certain foods from your diet can help prevent kidney stones and support the overall health of your kidneys.

Here are the top 10 foods that trigger kidney stones.

1. Oxalate-Rich Foods

Kidney stones form due to a buildup of calcium oxalate, so eating oxalate-rich foods in high amounts can increase your risk. The oxalate found in urine combines with calcium to form calcium-oxalate kidney stones.

People who are at a higher risk of developing kidney stones should eat oxalate-rich foods in moderation. This includes foods like spinach, rhubarb, okra, beetroot, kale, celery, soy milk, strawberries and Swiss chard.

Also, keep your vitamin C intake to appropriate levels. Extra vitamin C may turn into oxalate.

2. Sardines

People who are at a higher risk of developing uric acid stones should avoid foods that are high in purines, such as sardines. A high intake of purine increases the amount of uric acid in the urine and can lead to uric acid stones.

According to the American Urological Association, high intake of purine from animal protein, particularly from fish, can lead to hyperuricemia and hyperuricosuria in healthy individuals without stones.

Furthermore, purine-rich foods may trigger calcium-oxalate stones, because they increase the amount of calcium excreted in urine.

Limit your intake of sardines to once or twice a week and keep a close eye on the portion size, too. Other purine-rich foods that you should eat in moderation are anchovies, organ meats, bacon, scallops, shrimp and baker’s yeast.

3. Red Meat

Eating too much red meat, which is high in protein, can increase your risk of developing kidney stones. It is high in uric acid, a common cause of kidney stones.

Plus, the kidneys help metabolize and excrete nitrogen by-products from protein digestion. So,eating a high-protein diet increases the metabolic load on the kidneys.

Avoid eating red meat on a daily basis. Instead, limit your intake to once or twice a week.

4. Carbonated Drinks

Regularly drinking carbonated beverages, such as soda (with or without artificial sweetener), energy drinks and certain bottled juices, also increases the risk of developing kidney stones as well as kidney disease.

A 2007 study published in Epidemiology noted that cola beverages contain phosphoric acid that causes urinary changes and promotes kidney stones. It also increases the risk of chronic kidney disease.

In addition, a 2013 study published in the Clinical Journal of the American Society of Nephrology noted that intake of sugar-sweetened soda and punch is associated with a higher risk of stone formation.

Instead of drinking carbonated beverages, stick to plain water, flavored water, lemon water or fresh orange juice.

5. Non-Fermented Soy

Soybeans and soy-based foods that are genetically modified are harmful to the body and can affect the health of your kidneys. They contain high levels of oxalates, which bind with calcium in the kidneys to form kidney stones.

A 2009 study published in the International Journal of Biological Sciences analyzed the effects of GMO foods on mammalian health and concluded that the effects were mostly concentrated in kidney and liver function.

Plus, unfermented soy products like soy milk and tofu contain high levels of anti-nutrients including oxalates.

When buying soybeans, opt for organically grown varieties. Also, choose fermented soy products like miso and tempeh.

6. Refined Carbohydrates

Refined carbohydrates (such as refined sugar, white rice, refined flour and so on) make the body produce high levels of insulin, which causes calcium from the bones to end up in the urinary tract.

This triggers the formation of calcium-oxalate kidney stones. In contrast, complex carbohydrates take much longer to digest and cause only a small, slow rise in blood glucose and insulin levels.

A 1986 study published in Food and Chemical Toxicology highlighted the effect of dietary refined sugars and sugar alcohols on renal calcium-oxalate deposition in ethylene glycol-treated rats.

If you are at risk of developing kidney stones, avoid anything made with white or all-purpose flour.

7. Excessive Caffeine

Too much caffeine, either from food or drinks, can increase calcium excretion in your urine, which in turn can trigger kidney stones.

A 2004 study published in the Journal of Urology analyzed acute caffeine effects on urine composition and found that caffeine intake may modestly increase risk of calcium-oxalate stone formation.

Caffeine also has a diuretic effect that causes frequent urination and can lead to dehydration, a risk factor for kidney stones.

Furthermore, high caffeine intake can cause a range of health problems, including high blood pressure and insomnia.

Consume caffeinated foods and beverages in moderation. Do not drink more than 2 cups of coffee or 3 cups of tea per day.

In addition, limit your intake of sodas, energy drinks, chocolate, cocoa, and certain over-the-counter medications.

8. Artificial Sweeteners

Many of us use artificial sweeteners instead of sugar in our coffee or tea to cut calories. However, artificial sweeteners may impair kidney function if consumed on a regular basis.

A 2009 study published in the American Society of Nephrology journal found that people who consume a diet high in sodium or artificially sweetened drinks are more likely to experience a decline in kidney function.

Plus, artificial sweeteners have a strong acid-forming effect on your blood. This increases the amount of calcium deposits in your body, which leads to the formation of large, calcium-based kidney stones.

Instead of artificial sweeteners, use honey or stevia in your coffee or tea to add sweetness. 

9. Excessive Drinking

Drinking in moderation is fine, but drinking alcoholic beverages in excess can cause significant damage to your kidneys as well as liver.

Alcohol acts as a diuretic, which may lead to more urine production and increase your risk of dehydration. Dehydration disrupts normal kidney functioning.

Plus, it may interfere with the body’s ability to excrete uric acid, which can lead to the formation of kidney stones.

In contrast, moderate consumption of alcohol may offer some protection against stone formation. Moderation means no more than 2 drinks per day for men and no more than 1 drink per day for women.

10. Table Salt

Excessive use of table salt, which is sodium chloride, can contribute to the development of kidney stones. High sodium intake encourages water retention and the kidneys are not able to flush out excess sodium from your body. It even increases calcium levels and reduces citrate (a stone inhibitor) levels in urine.

Furthermore, high sodium intake raises blood pressure, which can lead to heart disease, a stroke, heart failure and kidney disease.

If you are susceptible to calcium stones, limit your salt intake to 3 grams per day. Instead of regular table salt, use just a pinch of high quality Celtic or Himalayan sea salt.

Also, use herbs and spices to add flavor to your food. In addition, avoid processed foods, which are usually high in sodium.