Protein, Dietary Patterns and Kidney Stones. What the Latest Research Reveals
- Alastair Hunt
- Jun 12
- 6 min read
Updated: Jun 13
Kidney stones are an increasingly common health problem, affecting up to 12% of the global population at some point in their lives. As well as being painful, they carry long-term risks, including chronic kidney disease and increased healthcare costs. Diet plays a central role in both preventing and managing kidney stones but evidence around protein intake and broader dietary patterns has often been conflicting.
Three major studies published in recent years offer fresh insight. One examines the effects of animal and dairy protein, another evaluates the safety of higher protein intake more generally, and the third explores the link between healthy dietary patterns, biological ageing, and kidney stone risk. Together, these studies help clarify which foods may raise or reduce risk - and why.
As ever, please talk to your doctor or medical practitioner most familiar with your medical history before implementing any changes in diet, exercise or lifestyle, especially if you are under treatment. Links to all studies at bottom of page.
The Protein Type Puzzle: What Role Do Meat and Dairy Play?
The 2022 systematic review in Advances in Nutrition analysed 14 large cohort studies involving over 1.6 million participants. Its aim was to assess whether total protein, animal protein, or specific animal protein sources were linked to kidney stone formation.
The study found that the type of protein mattered far more than the total amount consumed. Higher intakes of processed meat were associated with a 29% greater risk of developing kidney stones. Red meat, in particular, was linked to a 39% increase in risk for each additional 100 grams consumed daily. Total meat and meat products increased risk by 22%, while non-dairy animal proteins such as poultry and eggs raised the likelihood by 11%.
In contrast, dairy protein had a protective effect. People who consumed the most dairy protein were 9% less likely to develop kidney stones than those who consumed the least. This may be because calcium in dairy can bind to oxalates in the gut, reducing their absorption and subsequent excretion in urine - an important mechanism in preventing calcium oxalate stones, the most common type.
Importantly, total protein intake and fish or poultry consumption were not significantly associated with kidney stone risk. Nor were skimmed or whole milk.
The credibility of evidence varied, with most findings rated as low or very low using the NutriGrade system. Some results also changed significantly when individual studies were removed in sensitivity analyses, highlighting the need for caution in interpreting the data.
Is High Protein Dangerous for Healthy Kidneys?
In 2023, a comprehensive umbrella review published in the European Journal of Nutrition evaluated the potential long-term risks of high protein intake (defined as more than 0.8 grams per kilogram of body weight per day) on kidney health. This review analysed nine previous systematic reviews, including both randomised trials and prospective cohort studies, focusing on chronic kidney disease, kidney stones, and markers such as glomerular filtration rate (GFR), urinary albumin, and serum urea.
The overall conclusion was reassuring. For healthy individuals, there was no convincing evidence that higher protein intake caused kidney disease or increased the risk of kidney stones. Increases in GFR and urinary calcium were observed with higher protein intake, but these were interpreted as normal physiological responses rather than signs of kidney damage.
For kidney stone risk specifically, the review concluded that evidence was only “possible” that animal protein had no impact, suggesting no strong link either way. The authors highlighted that while higher protein diets may increase urinary acid and calcium excretion - factors associated with stones - these changes are not necessarily harmful in themselves, particularly if balanced by other dietary factors like fruit and vegetable intake.
That said, most of the included studies were of short duration, and the authors stressed the need for long-term research, especially in older adults or those with other risk factors. They also pointed out that while total protein intake did not pose a risk, the type of protein - animal versus plant - was not well explored in most studies.
Diet, Biological Age and Kidney Stones: A Bigger Picture
A 2025 study published in Frontiers in Nutrition took a broader view, using data from over 26,000 adults in the US National Health and Nutrition Examination Survey (NHANES). Instead of looking at protein alone, the researchers assessed the impact of four established healthy dietary patterns: the Mediterranean diet, the DASH diet, the Alternative Healthy Eating Index (AHEI), and the Healthy Eating Index 2020 (HEI-2020).
People with the healthiest diets, based on these indices, were significantly less likely to report having kidney stones. Specifically, higher adherence to these diets reduced the odds of kidney stone prevalence by 19% to 33%, depending on the scoring system used.
This study also introduced a new layer of insight by examining biological age, measured using two algorithms - Klemera-Doubal Method Age (KDMAge) and Phenotypic Age (PhenoAge). These markers predict an individual's physiological age based on biomarkers like creatinine, albumin, blood pressure, and inflammatory markers. Higher biological age was strongly associated with a greater risk of kidney stones. The researchers went further, showing that biological age partly explained the relationship between diet and kidney stones. That is, healthy diets seemed to reduce the risk of kidney stones in part by slowing the ageing process.
This connection between diet, ageing, and kidney stones is particularly important. As we age, the kidneys become less efficient at maintaining mineral balance and excreting waste. These physiological changes make the body more prone to developing stones. The study’s findings suggest that healthy eating may not only improve nutrient intake directly but also reduce the biological wear and tear that predisposes someone to kidney stone formation. By lowering inflammation, oxidative stress and supporting better metabolic function, healthy diets may offer dual protection - both immediate and over time.
Machine learning analysis confirmed the importance of dietary quality. Among individual nutrients, high intake of saturated fats emerged as a particularly strong predictor of kidney stone risk.
Although this was an observational study and relied on self-reported history of kidney stones, its use of advanced statistical models and biological markers adds a compelling new dimension to our understanding of how diet influences stone risk.
Practical Takeaways
For those looking to reduce their risk of kidney stones, the evidence supports a few key actions.
Prioritising a balanced, whole-food diet - such as those modelled on the Mediterranean or DASH patterns. - appears protective.
Limiting red and processed meats while including moderate amounts of dairy protein is also advisable. Total protein intake is less concerning than the sources it comes from.
Lastly, long-term dietary habits that promote healthy ageing may provide additional defence against stone formation.
Final Thoughts
These three studies provide a rich, complementary view of how diet affects kidney stone risk. While total protein intake does not appear to be a problem for most healthy people, the type of protein makes a significant difference. Processed and red meats are consistently linked with higher risk, whereas dairy protein may be protective.
Equally important is the wider dietary context. Diets rich in fruits, vegetables, whole grains, and low-fat dairy - such as the Mediterranean or DASH diets - consistently reduce the risk of kidney stones. These benefits may be partly due to their role in regulating biological ageing, a factor now emerging as a key player in stone formation.
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Stay Healthy,
Alastair
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Related Studies and Resources
Wei C, Yang Q, He J, Luo Y, Han K, Li J, Su S, Zhang J, Wang H, Wang D. Healthy dietary patterns, biological aging, and kidney stones: evidence from NHANES 2007-2018. Front Nutr. 2025 Mar 25;12:1538289. doi: 10.3389/fnut.2025.1538289. PMID: 40201586; PMCID: PMC11975591.
Remer T, Kalotai N, Amini AM, Lehmann A, Schmidt A, Bischoff-Ferrari HA, Egert S, Ellinger S, Kroke A, Kühn T, Lorkowski S, Nimptsch K, Schwingshackl L, Zittermann A, Watzl B, Siener R; German Nutrition Society. Protein intake and risk of urolithiasis and kidney diseases: an umbrella review of systematic reviews for the evidence-based guideline of the German Nutrition Society. Eur J Nutr. 2023 Aug;62(5):1957-1975. doi: 10.1007/s00394-023-03143-7. Epub 2023 May 3. PMID: 37133532; PMCID: PMC10349749.
Asoudeh F, Talebi S, Jayedi A, Marx W, Najafi MT, Mohammadi H. Associations of Total Protein or Animal Protein Intake and Animal Protein Sources with Risk of Kidney Stones: A Systematic Review and Dose-Response Meta-Analysis. Adv Nutr. 2022 Jun 1;13(3):821-832. doi: 10.1093/advances/nmac013. PMID: 35179185; PMCID: PMC9156392.
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