Researchers studied nearly 28,000 American adults to see if eating a Mediterranean-style diet could help prevent kidney stones. The Mediterranean diet focuses on vegetables, fruits, whole grains, fish, and olive oil while limiting red meat. People who followed this diet most closely had about 23% lower chances of developing kidney stones compared to those who followed it least. While this study shows a promising connection, it doesn’t prove the diet prevents kidney stones—it just shows the two are linked. More research is needed to confirm whether changing your diet can actually prevent kidney stones from forming.

The Quick Take

  • What they studied: Whether eating foods from the Mediterranean diet (lots of vegetables, fruits, fish, and olive oil) is connected to a lower chance of getting kidney stones
  • Who participated: About 28,000 American adults aged 20 and older who answered detailed questions about what they eat and whether they’ve ever had kidney stones. About half were men and half were women, with an average age of 48 years
  • Key finding: People who followed the Mediterranean diet most closely had a 23% lower risk of kidney stones compared to those who followed it the least. This difference was statistically significant, meaning it’s unlikely to be due to chance alone
  • What it means for you: Eating more Mediterranean-style foods might help reduce your kidney stone risk, but this study only shows a connection—it doesn’t prove the diet prevents stones. If you’re prone to kidney stones, talk to your doctor about dietary changes before making major shifts

The Research Details

This was a cross-sectional study, which means researchers looked at a large group of people at one point in time and compared their eating habits to their kidney stone history. The researchers used data collected between 2007 and 2018 from the National Health and Nutrition Examination Survey, a program that tracks Americans’ health and eating patterns. Participants answered detailed questions about everything they ate over a 24-hour period, and they reported whether they’d ever been told by a doctor that they had kidney stones. The researchers then scored how closely each person followed a Mediterranean diet pattern, dividing people into four groups from lowest to highest adherence.

This approach is useful for spotting patterns in large populations and can suggest which diets might be worth studying more carefully. However, because it’s a snapshot in time rather than following people over years, we can’t be completely sure that the diet caused the lower kidney stone risk—other factors in people’s lives could explain the connection. This type of study is often the first step before doing more expensive and time-consuming experiments

The study used a large, representative sample of American adults, which makes the findings more likely to apply to the general U.S. population. The researchers adjusted their analysis for many other factors that could affect kidney stone risk, like age, sex, and overall health. However, because people reported their own diets from memory, there could be some inaccuracy. Also, people who reported having kidney stones might remember their diet differently than those without stones

What the Results Show

Out of 28,059 adults studied, about 1 in 10 (10.08%) reported having had kidney stones at some point. When researchers compared people eating the most Mediterranean-style foods to those eating the least, they found a clear pattern: higher Mediterranean diet scores were linked with lower kidney stone risk. The strongest finding was that people in the highest group (eating the most Mediterranean foods) had about 23% lower odds of kidney stones compared to the lowest group. This relationship appeared to be linear, meaning that as people ate more Mediterranean foods, their kidney stone risk gradually decreased—there wasn’t a sudden drop at any particular point.

The researchers also looked at specific subgroups of people (like men versus women, different age groups, and people with different body weights) to see if the Mediterranean diet connection worked the same way for everyone. The pattern held fairly consistently across different groups, suggesting the benefit isn’t limited to just one type of person. This consistency strengthens the evidence that the diet itself, rather than something unique about certain groups, is responsible for the lower kidney stone risk

Previous research has suggested that diet plays an important role in kidney stone formation, particularly the amount of calcium, sodium, and certain proteins people consume. The Mediterranean diet is naturally lower in some risk factors for kidney stones and higher in protective compounds like citrate (found in citrus fruits) and magnesium. This study adds to that body of evidence by showing that following an overall Mediterranean eating pattern is associated with lower kidney stone risk, rather than just focusing on individual nutrients

This study shows a connection between diet and kidney stones but can’t prove that the diet prevents stones. People reported their own diets and kidney stone history, which could be inaccurate. The study was done at one point in time, so we don’t know if people’s diets or kidney stone risk changed over time. Additionally, the study only included Americans, so results might not apply to other populations. Finally, people who have had kidney stones might have already changed their diets, which could affect the results

The Bottom Line

If you want to reduce your kidney stone risk, eating more Mediterranean-style foods appears to be a reasonable approach based on this evidence. This means eating more vegetables, fruits, whole grains, fish, and olive oil while eating less red meat. However, this is observational evidence (moderate confidence), not proof from a controlled experiment. If you have a personal or family history of kidney stones, consult your doctor or a dietitian before making major dietary changes, as individual needs vary

People with a personal or family history of kidney stones should find this information most relevant. Anyone interested in heart-healthy eating will also benefit, since the Mediterranean diet has strong evidence for heart health. People without kidney stone risk may still enjoy the general health benefits of this diet. Those with certain medical conditions affecting kidney function should check with their doctor before making changes

If you switch to a Mediterranean diet, you wouldn’t expect to see immediate results. Kidney stone prevention is a long-term process. It may take weeks to months of consistent eating pattern changes to see potential benefits. The study looked at people’s overall eating habits over time, suggesting that sustained dietary changes are more important than short-term adjustments

Want to Apply This Research?

  • Track daily servings of Mediterranean diet components: vegetables (goal: 3+ servings), fruits (goal: 2+ servings), whole grains (goal: 2+ servings), fish (goal: 2-3 times per week), and olive oil use. Also monitor water intake (goal: 8+ glasses daily) since hydration is important for kidney stone prevention
  • Start by adding one Mediterranean element to each meal: add vegetables to breakfast, choose fish instead of red meat for lunch, snack on fruits and nuts, and use olive oil for cooking dinner. Gradually increase adherence rather than making drastic changes all at once
  • Weekly check-ins on Mediterranean diet adherence using a simple scoring system. Monthly reviews of dietary patterns and any changes in symptoms. For those with kidney stone history, track hydration levels and dietary consistency. Share progress with a healthcare provider at regular checkups to ensure the dietary changes are working for your individual situation

This research shows a connection between Mediterranean diet adherence and lower kidney stone risk, but it does not prove that changing your diet will prevent kidney stones. This study is observational and cannot establish cause-and-effect relationships. Individual kidney stone risk depends on many factors including genetics, medications, medical conditions, and hydration levels. If you have a history of kidney stones or are concerned about kidney stone risk, consult with your doctor or a registered dietitian before making significant dietary changes. This information is for educational purposes and should not replace professional medical advice. Always discuss dietary modifications with your healthcare provider, especially if you have existing kidney disease or other medical conditions.