Researchers tested whether eating a diet rich in vegetables and fruits could help prevent kidney stones as well as a common medication does. They studied 46 people who had experienced kidney stones before, dividing them into three groups: one that changed their diet, one that took medication, and one that made no changes. After four weeks, the medication group showed the strongest results, but the diet group also showed some modest improvements in their urine chemistry that could help prevent stones from forming. This suggests that dietary changes might be a helpful tool, though they may work more slowly than medication.

The Quick Take

  • What they studied: Whether eating a diet focused on vegetables, fruits, and less meat could help prevent kidney stones by changing the chemistry of urine, compared to taking a potassium citrate medication.
  • Who participated: 46 adults who had experienced kidney stones before were randomly assigned to three groups: a diet-change group (14 people), a medication group (16 people), and a control group that made no changes (16 people).
  • Key finding: The medication group showed clear improvements in urine chemistry within two weeks that continued through four weeks. The diet group showed slower, more modest improvements in making urine less acidic and increasing protective potassium levels, but these changes were not statistically significant.
  • What it means for you: If you’ve had kidney stones, medication appears to work faster and more reliably than diet alone in the short term. However, dietary changes toward more plants and less meat may offer some benefit over time, though more research is needed to confirm this works long-term.

The Research Details

This was a randomized controlled trial, which is considered one of the strongest types of research studies. Researchers randomly assigned 46 people who had previously experienced kidney stones into three equal groups. One group changed their diet to include more vegetables, fruits, and less animal protein (the low PRAL diet). Another group took potassium citrate medication in extended-release form. The third group made no changes and served as a comparison. All participants provided urine samples at the start, after two weeks, and after four weeks. The researchers measured nine different components in the urine that affect kidney stone formation, including citrate (a protective substance), calcium, oxalate, and urine acidity level.

The study design allowed researchers to compare how well diet changes worked compared to medication and compared to doing nothing. By measuring urine samples at multiple time points, they could track whether changes happened quickly or gradually. This approach helps determine not just whether something works, but how fast it works and how strong the effect is.

Understanding whether dietary changes can prevent kidney stones is important because it offers people a non-medication option. Many people prefer to make lifestyle changes rather than take medications long-term. However, researchers need to know if diet actually works well enough to recommend it. This study helps answer that question by directly comparing diet to a proven medication, giving people and doctors real information to make decisions.

This study has several strengths: it randomly assigned people to groups (reducing bias), it measured objective urine chemistry (not just what people reported), and it had a control group for comparison. However, the study is small (only 46 people) and lasted only four weeks, which is a short time to judge whether dietary changes prevent kidney stones long-term. The researchers note this is a preliminary study, meaning more research is needed. The groups were generally similar at the start, which is good, though the diet group started with slightly different citrate levels. The study was well-designed but limited in scope.

What the Results Show

The medication group showed clear, statistically significant improvements compared to the control group. Specifically, their urine potassium levels increased and their urine became less acidic (higher pH) within two weeks, and these improvements continued through week four. These changes are important because higher potassium and less acidic urine help prevent calcium oxalate stones from forming.

The diet group showed a different pattern. While their improvements were not statistically significant (meaning they could partly be due to chance), the researchers observed that the diet group gradually showed slight improvements in the same protective factors—urine potassium increased and urine became slightly less acidic. However, the diet group did not show meaningful changes in other important stone-forming factors like calcium, sodium, chloride, or oxalate levels.

The control group, which made no changes, showed no improvements in any of these measures. This confirms that both the diet and medication approaches produced changes, but the medication worked faster and more reliably. The diet changes appeared to work in the right direction but much more slowly and modestly.

The study measured nine different urine components related to kidney stone formation. Beyond the primary findings about potassium and acidity, the researchers found that neither the diet nor medication significantly changed oxalate levels (a major stone-forming substance) or calcium levels during the four-week period. Urine volume also did not change significantly in any group. These findings suggest that while the diet and medication can make urine less acidic and increase protective potassium, they may not address all the factors that contribute to stone formation.

Previous research has suggested that diet changes toward more plant-based foods and less animal protein can help prevent kidney stones. This study partially supports that idea but shows the effect is much weaker and slower than medication. The medication used (potassium citrate) is already well-established as an effective kidney stone prevention treatment, and this study confirms it works quickly. The finding that diet works more slowly aligns with how we understand nutrition—dietary changes typically produce gradual shifts in body chemistry rather than rapid changes.

This study has important limitations that readers should understand. First, it only lasted four weeks, which is too short to determine if dietary changes actually prevent kidney stones from forming. Kidney stone prevention is a long-term concern, so researchers would need to follow people for months or years to know if diet truly works. Second, the study included only 46 people, which is a small number. Larger studies are needed to be confident in the results. Third, the researchers did not measure whether people actually stuck to the diet, so we don’t know if the modest results were due to the diet not working or people not following it well. Fourth, the study only measured urine chemistry changes, not actual kidney stone formation. Finally, the study was preliminary, meaning it was designed as a first step to see if a larger study would be worthwhile.

The Bottom Line

For people with a history of kidney stones, potassium citrate medication appears to be the more reliable short-term option based on this research (moderate confidence). Dietary changes toward more vegetables, fruits, and less meat may offer some benefit, but the evidence from this study is weak (low confidence). The best approach may be to discuss both options with a doctor. If someone wants to try dietary changes, they should be aware it may take longer to see results than with medication. Anyone with kidney stones should also drink plenty of water, as hydration is one of the most important prevention strategies.

People who have had kidney stones before should pay attention to this research, as it directly applies to them. Those interested in preventing kidney stones through diet rather than medication may find this helpful. However, people without a history of kidney stones don’t need to make major dietary changes based on this study. People with certain medical conditions (like kidney disease or heart problems) should talk to their doctor before making dietary changes or taking supplements, as some recommendations may not be appropriate for them.

Based on this study, if someone takes potassium citrate medication, they might expect to see changes in urine chemistry within two weeks. If someone tries dietary changes, they should expect much slower results—the modest improvements in this study took the full four weeks to appear, and even then were not dramatic. Realistically, someone trying dietary prevention should commit to at least several months to see if it helps prevent new stones. The actual prevention of kidney stone formation (not just urine chemistry changes) would take even longer to measure.

Want to Apply This Research?

  • Track daily intake of vegetables and fruits (servings per day) and animal protein portions (servings per day). Also track urine color as a simple proxy for hydration—pale yellow urine suggests good hydration, which is crucial for stone prevention. Users could log these daily and review weekly trends.
  • Users could set a specific goal like ‘add one extra vegetable serving daily’ or ‘reduce red meat to 3 days per week’ rather than making drastic changes all at once. The app could provide meal suggestions that fit a low-PRAL diet pattern and send reminders to drink water throughout the day. Users could also log any kidney stone symptoms or concerns to discuss with their doctor.
  • Over 8-12 weeks, users should track whether they’re maintaining dietary changes and monitor for any kidney stone symptoms (pain, blood in urine, urinary urgency). Users should also schedule follow-up urine tests with their doctor to see if their urine chemistry is improving. The app could generate monthly reports showing dietary adherence and symptom patterns to share with healthcare providers.

This research is preliminary and based on a small study lasting only four weeks. It should not replace medical advice from your doctor. If you have a history of kidney stones or are experiencing symptoms like flank pain, blood in urine, or urinary problems, consult a healthcare provider before making significant dietary changes or starting any treatment. This study measured urine chemistry changes, not actual kidney stone prevention—longer-term research is needed to confirm whether these dietary changes actually prevent stones from forming. Individual results may vary based on genetics, medical history, and other factors not addressed in this study.