Helpful prevention tips for the four most common types of kidney stones

Xray showing multiple types of kidney stones

Kidney stones are a relatively common urinary condition, affecting almost twice as many men as women. It is estimated that 13% of men and 7% of women worldwide will experience one of the various types of kidney stones at some point in their life. As many as 600,000 individuals in the US deal with kidney stones each year. Of those who form an initial stone, up to 50% will form stones again.

Forming kidney stones may increase your risk of developing other issues such as chronic kidney disease, end-stage renal failure, cardiovascular disease, diabetes, and high blood pressure. Like other chronic health conditions, the incidence of kidney stone formation is on the rise. Obesity, lack of physical activity, poor dietary habits, low water intake, and even climate change have been shown to be contributing factors.

Smaller stones (less than 5 millimeters) will usually pass on their own. It’s even possible for stones as large as 10 millimeters to pass on their own (though about 50% of stones this size require medical treatment). Larger stones need to be broken up or surgically removed to ensure they don’t cause bigger issues.

The pain and discomfort associated with a kidney stone can be excruciating, whether passing it yourself or having it surgically removed. This is certainly an example of an ounce of prevention is worth a pound of cure. Having dealt with a couple of stones in my lifetime, I can tell you it’s worth attempting some of the research-backed prevention strategies presented here if it means avoiding dealing with another stone in the future.

4 Types of Kidney Stones (and a bonus!)

While we commonly refer to all kidney stones as the same, the fact is they are not and there are actually several different types of kidney stones. Due to a number of factors, the composition, causes, and potential prevention and treatment vary.

If you pass a kidney stone, it’s important to try and save it so your doctor can submit it to a lab to determine the chemical composition. While knowing this is helpful to provide some direction on preventive measures, it won’t give the reason why the stone was formed. To help prevent stones from recurring in the future, it’s also critical to find out if there is an underlying condition that may cause too much of a specific chemical in your urine. Or it could be as simple as not drinking enough water or eating too much animal protein.

A 24-hour urine collection test is a simple test that is done at home. This test, which is ordered by a physician, looks at risk factors such as urine volume, urinary pH, and how much calcium, oxalate, citrate, uric acid, and magnesium are being excreted. It can be a useful tool in helping to determine your risk of developing stones.

  • Calcium stones. These are by far the most common stones, making up about 80% of kidney stones worldwide. This group actually consists of two types, calcium oxalate stones and calcium phosphate stones. The former are more common.
  • Struvite stones. Coming in at a distant second place, stones made of magnesium ammonium phosphate account for roughly 10%.
  • Uric acid stones. Neck and neck with struvite, uric acid stones represent only around 9% of all stones.
  • Cystine stones. These are a lot less common, only accounting for about 1% of kidney stones.
  • Bonus type: This group is made up of stones that are caused by the oversaturation of the urine due to certain insoluble drugs or compounds with low solubility that can find their way into foods, such as melamine.

There are some universal interventions that appear to help prevent stones in general, these include:

There are also those that are specific to each type of stone. Here we’re going to look at helpful preventative tips for each of the types of kidney stones. As always, consult with your doctor or health practitioner so they can help you determine what type of stone you have and the best course of treatment, and what specific preventative measures may work best for your specific condition.

Calcium Stones.

What are they?

The most common type of kidney stone, calcium oxalate (CaOx) and calcium phosphate (CaP) stones can be formed just as CaOx or CaP stones or a combination of the two. They can be smooth or jagged.

What causes them?

Calcium stones can be caused by a number of different factors including:

  • Eating a diet too high in oxalates. Some of the worst offenders are spinach, rhubarb, beets, potato chips, french fries, and nuts.
  • Health conditions such as:
    • Hypercalciuria is when your kidneys release too much calcium into your urine.
    • Hypocitraturia is when the amount of citrate in your urine is too low. Citrate has been shown to inhibit the formation of calcium stones.
    • Primary hyperparathyroidism is a condition where your parathyroid glands make too much parathyroid hormone (PTH). This results in too much calcium in the bloodstream, which leads to too much calcium in the urine, which ultimately results in kidney stones.
    • Issues such as inflammatory bowel disease that cause an imbalance in how nutrients are absorbed.
  • Alkaline pH.
  • There may be a possible connection between bacteria, frequent UTIs, and calcium stones.

Prevention tips.

Struvite Stones.

What are they?

Once feared for their high mortality, they are now more associated with a high rate of recurrence. These stones tend to grow more quickly than calcium and have an appearance like puzzle pieces. Struvite stones are more common in women. Struvite stones are often too large to pass and must be removed surgically.

What causes them?

Struvite stones only form in alkaline urine. Also referred to as “infection stones,” these are always associated with UTIs. Frequent bacterial infections in the upper urinary tract cause an increase in ammonia. The bacteria produce ammonia as a waste product, which causes the urine pH to go up. This can lead to the formation of stones.

Prevention tips.

  • There are some studies that indicate L-methionine may be helpful at reducing the risk of developing struvite stones:
    • In a 2016 study, researchers found that 1500mg of L-methionine lowered urinary pH and reduced the supersaturation of struvite by 34%.
    • A 1996 study found that doses of 1500mg to 3000mg of L-methionine per day reduced the recurrence of struvite stones.

Uric Acid Stones.

What are they?

Uric acid stones may be more likely to develop in those who are obese and insulin resistant. These stones tend to be packed and pebble-like in appearance. They can often be hard on the outside and softer on the inside.

What causes them?

One of the main risk factors responsible for the formation of uric acid stones is urine that is overly acidic (a pH under 5.5). There are some underlying conditions that are also potential risk factors. These include:

  • Hyperuricosuria – a condition where there is too much uric acid excreted in the urine.
  • Hyperuricemia – a condition where there is a buildup of uric acid in the blood.
  • Diabetes is a possible risk factor due to insulin resistance leading to low urinary pH.
  • Gout

Additional risk factors for developing uric acid stones include:

  • Research suggests that the metabolic issues caused by chemotherapy can lead to the development of uric acid stones.
  • Not drinking an adequate amount of water each day.
  • Acidic urine pH.
  • Eating a diet high in animal protein or purine-rich foods such as red meat, organ meats, some fish, and some vegetables.

Prevention tips.

  • Eat a diet rich in fruits and vegetables to help make the urine more alkaline.
  • Limit alcohol intake. Some alcohol, especially beer, can be high in purines.
  • Avoid sugar to control your blood sugar levels.
  • Cut down on the amount of high-purine foods you eat, such as red meat, organ meats, shellfish, and tuna.
  • Limit the amount of animal protein you eat as they tend to be high in purines and can increase urinary uric acid.
  • Add 1/4 – 1/2 tsp of baking soda to a glass of water several times per day to help increase the pH of your urine. (If testing urine pH with urine strips, shoot for about 7.0.)

Cystine Stones.

What are they?

These stones are compact and amber in color. The crystals that form these stones have a unique structure.

What causes them?

These stones are most likely due to a rare hereditary disorder called cystinuria. This condition causes you to produce, and excrete excess cystine. Cystinuria is a lifelong condition.

Acidic urine pH can also be a risk factor.

Prevention tips.

  • Drinking enough water is one of the top tips for helping to prevent cystine stones. The goal here is at least 100 ounces of water per day.
  • Eat a diet rich in fruits and vegetables to help make the urine more alkaline.
  • Add 1/4 – 1/2 tsp of baking soda to a glass of water several times per day to help increase the pH of your urine. (If testing urine pH with urine strips, shoot for between 7.0 – 8.0).
  • Restrict your intake of sodium as this can decrease urinary elimination of cystine.
  • Limiting your intake of protein can also decrease the amount of cystine in urine.
  • Alcohol consumption can make you dehydrated, so it’s a good idea to limit your intake.

Bonus Type Stones.

What are they?

These stones are much rarer and account for only about 1% of all stones.

What causes them?

These stones can be caused by various medications such as guaifenesin (Mucinex), triamterene (Dyrenium, a blood pressure medication), atazanavir (Reyataz, an HIV medication), and sulfa drugs.

Prevention tips.

With drug-induced kidney stones, it’s important to work with your doctor to determine the cause. A particular drug may be causing issues that can be countered with some of the preventive measures above. However, it may also be necessary to discontinue the drug.

Conclusion

The prevalence of kidney stones is on the rise. Research estimates that those who form one stone have as high as a 75% chance of forming new stones unless they make diet or lifestyle modifications. Thankfully, there are changes that can be helpful in preventing a recurrence, regardless of the type of kidney stone.

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