Researchers studied over 25,000 American adults to understand how different healthy eating patterns affect kidney stone risk. They found that people who followed healthier diets—like the Mediterranean diet or DASH diet—were less likely to develop kidney stones. The study suggests that healthy eating works partly by keeping uric acid levels lower, which is a chemical that can contribute to kidney stone formation. This research shows that what you eat really does matter for preventing painful kidney stones.

The Quick Take

  • What they studied: Whether eating healthier foods can reduce the chances of getting kidney stones, and whether this protection works by lowering uric acid (a chemical in your body)
  • Who participated: 25,421 American adults from a large national health survey, of which 2,470 had experienced kidney stones before
  • Key finding: All four healthy eating patterns studied (Mediterranean, DASH, Healthy Eating Index, and Alternate Healthy Eating Index) were linked to lower kidney stone risk. The Healthy Eating Index was most protective, and uric acid levels explained about 2-26% of this protective effect depending on the diet type
  • What it means for you: Following a healthier diet may reduce your kidney stone risk, though this study shows a connection rather than proving diet prevents stones. If you’re at risk for kidney stones, eating more whole foods and fewer processed foods could be helpful, but talk to your doctor about your specific situation

The Research Details

This was a cross-sectional study, which means researchers looked at information from a large group of people at one point in time rather than following them over years. The researchers used data from the National Health and Nutrition Examination Survey (NHANES), which is a program that regularly surveys thousands of Americans about their health and eating habits from 2007 to 2018.

The researchers calculated four different healthy eating scores for each person based on what they reported eating. These scores measured how closely people followed Mediterranean-style eating, the government’s Healthy Eating Index, a modified healthy eating pattern, and the DASH diet (which stands for Dietary Approaches to Stop Hypertension). They then looked at whether people with higher scores on these diets were less likely to have had kidney stones.

To understand how diet affects kidney stones, the researchers also measured uric acid levels in participants’ blood. They used advanced statistical methods to see if lower uric acid levels explained why healthier diets seemed to protect against kidney stones.

This research approach is important because kidney stones are a common and painful problem affecting millions of Americans. By studying a large, representative sample of the US population, the findings are more likely to apply to real people rather than just a small group. The study also goes beyond just showing that diet matters—it tries to explain the mechanism (how it works), which helps us understand why these dietary changes might help.

This study has several strengths: it included a very large number of participants, used standardized health survey data, and employed sophisticated statistical methods to analyze multiple dietary patterns at once. However, because it’s a cross-sectional study, it shows associations rather than proving cause-and-effect. People who eat healthier might also exercise more or have other healthy habits that actually prevent kidney stones. Additionally, the study relied on people remembering what they ate, which can be inaccurate.

What the Results Show

All four healthy eating patterns showed a protective effect against kidney stones. The Healthy Eating Index-2020 was the most protective, followed by the DASH diet, Mediterranean diet, and Alternate Healthy Eating Index. When researchers looked at the combined effect of all four dietary patterns together, they found that people who scored higher on these healthy eating measures had significantly lower kidney stone risk.

The study found that uric acid played a role in this protection. Uric acid is a waste product your body makes when it breaks down certain foods, especially those high in purines (like red meat and organ meats). When uric acid levels get too high, it can contribute to kidney stone formation. The healthier diets appeared to work partly by keeping uric acid levels lower.

Interestingly, the Mediterranean diet showed the strongest mediation through uric acid (about 26% of its protective effect), while the Healthy Eating Index showed the smallest mediation effect (about 2.5%). This suggests that different healthy diets may protect against kidney stones through somewhat different mechanisms.

The researchers used two advanced statistical methods to analyze the data: one that weighted the importance of each diet type, and another that looked at how all the diets worked together. Both methods confirmed that healthier eating patterns were associated with lower kidney stone risk.

The study examined dose-response relationships, meaning whether eating even healthier (higher diet scores) led to even more protection. The results showed a consistent pattern where higher adherence to healthy eating was associated with progressively lower kidney stone risk, with no evidence of a threshold effect. This suggests that even modest improvements in diet quality could be beneficial.

Previous research has shown that diet influences kidney stone risk, and that uric acid is involved in stone formation. This study builds on that knowledge by comparing multiple dietary patterns in the same population and quantifying how much of the protective effect comes from uric acid reduction. The findings align with existing evidence that Mediterranean and DASH diets are beneficial for overall health, and extend that evidence to kidney stone prevention specifically.

The main limitation is that this study shows association, not causation—we can’t prove that changing your diet will prevent kidney stones based on this research alone. The study relied on dietary recall, which means people had to remember what they ate, and memory isn’t always accurate. Additionally, the study couldn’t account for all possible factors that influence kidney stone risk, such as hydration levels, family history, or certain medications. The cross-sectional design means we’re looking at a snapshot in time rather than following people forward to see who actually develops kidney stones.

The Bottom Line

If you want to reduce your kidney stone risk, consider adopting a healthier eating pattern, with the Healthy Eating Index or DASH diet showing the strongest evidence in this study. This means eating more fruits, vegetables, whole grains, and lean proteins while reducing processed foods, red meat, and foods high in sodium. Staying well-hydrated is also important for kidney stone prevention. These recommendations have moderate confidence based on this research, but should be combined with other preventive measures and personalized medical advice.

This research is most relevant for people who have had kidney stones before, have a family history of kidney stones, or have other risk factors like high uric acid levels. It’s also relevant for anyone interested in preventive health through diet. However, if you have kidney disease, gout, or other conditions affecting uric acid metabolism, you should work with your doctor on a personalized diet plan rather than following general recommendations.

Changes in uric acid levels can happen relatively quickly with dietary changes (weeks to months), but the actual prevention of kidney stone formation may take longer to observe. You might not see a difference in kidney stone risk for several months to a year of consistent healthy eating, since kidney stones develop over time.

Want to Apply This Research?

  • Track your adherence to one of the healthy eating patterns (Mediterranean, DASH, or Healthy Eating Index) by logging meals and calculating a weekly diet quality score. Specifically, monitor servings of fruits, vegetables, whole grains, and lean proteins versus processed foods and red meat.
  • Start by making one specific change: replace one processed food or red meat meal per week with a plant-based or fish-based meal. Track this change in the app and gradually increase the frequency as it becomes a habit.
  • Monthly, review your diet quality score and uric acid levels if available through your doctor. Set a goal to improve your diet score by 10% each month. If you have a history of kidney stones, also track any symptoms or recurrences and correlate them with your diet patterns over time.

This research shows an association between healthy eating patterns and lower kidney stone risk, but does not prove that diet changes will prevent kidney stones in any individual. If you have a history of kidney stones, are at risk for kidney stones, or have elevated uric acid levels, consult with your healthcare provider or a registered dietitian before making significant dietary changes. This is especially important if you have kidney disease, gout, or are taking medications that affect uric acid metabolism. This summary is for educational purposes and should not replace professional medical advice.