Can Fatty Liver Cause Kidney Stones?

Can fatty liver cause kidney stones? Research shows a meaningful association between non-alcoholic fatty liver disease (NAFLD) and an increased risk of kidney stones, driven largely by shared metabolic disturbances including insulin resistance, dyslipidaemia, and chronic inflammation. Both conditions frequently co-exist as part of a broader metabolic syndrome picture. Understanding the link, recognising symptoms early, and making targeted lifestyle changes can help protect both liver and kidney health. This article explains the evidence, the mechanisms involved, and the practical steps you can take.

Is there a link between fatty liver disease and kidney stones?

Observational studies and meta-analyses show people with NAFLD are more likely to develop kidney stones, driven by shared metabolic disturbances such as insulin resistance and obesity rather than a direct causal pathway.

Research does suggest a meaningful association between fatty liver disease and an increased risk of kidney stones, though the relationship is not yet fully established as directly causal. Several observational studies and meta-analyses have found that people with non-alcoholic fatty liver disease (NAFLD) are more likely to develop kidney stones than those without the condition, even after adjusting for shared risk factors such as obesity and type 2 diabetes.^[1][2]

NAFLD is the most common chronic liver condition in the UK, estimated to affect around one in three adults to some degree, according to NHS information on the condition.^[4][23] It encompasses a spectrum from simple fat accumulation in liver cells (steatosis) through to the more serious non-alcoholic steatohepatitis (NASH), which can progress to cirrhosis. Kidney stones affect a substantial proportion of the population at some point in their lives, with calcium oxalate and uric acid stones among the most commonly identified types in European populations.^[5]

The association between the two conditions is thought to be driven largely by shared metabolic disturbances, particularly insulin resistance, dyslipidaemia, and chronic low-grade inflammation. These overlapping mechanisms mean that fatty liver disease and kidney stones frequently co-exist as part of a broader metabolic syndrome picture, rather than one condition directly causing the other in a straightforward biological chain.

It is important to note that having fatty liver disease does not mean kidney stones are inevitable. However, the shared risk factors make it clinically sensible to consider kidney health when managing a patient with NAFLD, and vice versa. If you have been diagnosed with either condition, discussing the other with your GP is a reasonable step.

Why does fatty liver increase the risk of kidney stones?

Insulin resistance in NAFLD lowers urinary pH, promoting uric acid stone formation; disrupted bile acid metabolism may increase oxalate absorption, and chronic inflammation can reduce urinary citrate, a natural stone inhibitor.

Fatty liver disease is associated with an increased risk of kidney stones through several metabolic mechanisms, though the relative importance of each pathway is still being studied and the evidence base varies in strength.

One of the better-established mechanisms involves the kidneys' handling of ammonium in the context of insulin resistance. In people with insulin resistance, renal ammoniagenesis is impaired, which lowers urinary pH and makes the urine more acidic. Acidic urine is a well-recognised environment for uric acid crystallisation, and uric acid stones are disproportionately common in people with metabolic syndrome and NAFLD. This link between insulin resistance, low urinary pH, and uric acid stone formation is supported by evidence cited in urological guidelines.

A second proposed pathway involves oxalate handling. Disrupted bile acid metabolism in NAFLD may alter fat absorption in the small intestine, potentially leaving more fatty acids to bind calcium in the gut and allowing more dietary oxalate to be absorbed into the bloodstream. However, it should be noted that enteric hyperoxaluria is most clearly established in states of significant fat malabsorption, such as after bariatric surgery or in inflammatory bowel disease, and its contribution in uncomplicated NAFLD is less certain.^[8][9] This mechanism should be regarded as plausible but not definitively proven in this context.

Chronic low-grade inflammation, which is a hallmark of NASH in particular, may also contribute by altering renal tubular function and reducing urinary excretion of citrate, a natural inhibitor of stone formation. Additionally, obesity, which frequently accompanies NAFLD, is independently associated with higher urinary excretion of calcium, oxalate, and uric acid.^[11][12] Together, these mechanisms create a urinary environment that may be more conducive to stone formation, though the precise contribution of each factor in any individual will vary.

What symptoms should you look out for with both conditions?

Fatty liver is often silent early on, while kidney stones typically cause sudden severe flank pain, haematuria, nausea, and frequent urination; unexplained blood in the urine should be reported to your GP promptly.

Fatty liver disease in its early stages is often entirely silent, producing no symptoms at all, which is why it is frequently discovered incidentally during an ultrasound or blood test carried out for another reason. As the condition progresses, some people notice fatigue, a dull ache or discomfort in the upper right abdomen, or a general sense of feeling unwell. In more advanced disease, symptoms of liver dysfunction such as jaundice, swelling of the abdomen (ascites), or easy bruising may develop, and these warrant prompt medical review.

Kidney stones, by contrast, can cause very distinctive and often severe symptoms when a stone moves into the ureter. These include:

• Sudden, severe pain in the back, side, or lower abdomen, sometimes radiating to the groin

• Blood in the urine (haematuria), which may make urine appear pink, red, or brown

• Nausea and vomiting accompanying the pain

• Frequent or painful urination

• Cloudy or foul-smelling urine, which may indicate an associated urinary tract infection

Smaller stones may pass without causing significant pain, and some people only discover they have kidney stones during imaging for an unrelated complaint.

Visible blood in the urine without a clear explanation, even in the absence of pain, should be reported to your GP promptly, as it may require further investigation under NHS suspected cancer pathways (NICE guideline NG12).^[13]

You should contact your GP if you notice persistent abdominal discomfort, unexplained fatigue, or blood in your urine. If you develop sudden, severe flank or abdominal pain, particularly with fever, you should seek urgent assessment via NHS 111 or attend A&E, as an obstructed infected kidney is a medical emergency.

Can treating fatty liver help prevent kidney stones forming?

Managing NAFLD through lifestyle changes and, where appropriate, medicines such as GLP-1 receptor agonists may reduce the metabolic disturbances that drive stone formation, though no trials have directly tested this outcome.

Effectively managing fatty liver disease may reduce some of the metabolic disturbances that contribute to kidney stone risk, though no clinical trials have been identified that directly assess whether treating NAFLD prevents stone formation. The rationale for a protective effect is nonetheless plausible, given the shared mechanisms described above.

NICE guideline NG49 on NAFLD emphasises lifestyle modification as the cornerstone of management, including weight loss, dietary change, and increased physical activity. These same interventions are also recommended to reduce kidney stone recurrence, particularly for uric acid and calcium oxalate stones. Improving insulin sensitivity through weight loss, for example, raises urinary pH and reduces uric acid supersaturation, directly addressing one of the key stone-forming mechanisms.

For people with type 2 diabetes and NAFLD, certain glucose-lowering medicines may offer additional benefit. GLP-1 receptor agonists such as semaglutide (available as Wegovy at doses up to 7.2 mg weekly for weight management, or as Ozempic for type 2 diabetes) have demonstrated reductions in liver fat in clinical studies, including a randomised controlled trial published in the New England Journal of Medicine in 2021, and may improve the metabolic environment that drives stone formation.^[16] Tirzepatide (Mounjaro), which is MHRA-authorised both for type 2 diabetes and for chronic weight management, has also shown significant reductions in liver fat in trial data, including the SURPASS-3 MRI substudy.^[17][18] However, these medicines are not currently licensed specifically for kidney stone prevention, and their use should be guided by a clinician based on individual clinical need.

Regular monitoring of kidney function and urinary biochemistry in people with NAFLD is not yet standard NHS practice, but discussing your individual risk with your GP is worthwhile, particularly if you have had a kidney stone previously. NICE NG49 also recommends risk stratification for liver fibrosis using tools such as the FIB-4 score, and referral to hepatology where indicated.^[14]

Lifestyle changes that support both liver and kidney health

Weight loss, a Mediterranean-style diet, reduced salt and animal protein intake, adequate hydration, and at least 150 minutes of weekly moderate exercise benefit both liver and kidney health simultaneously.

A range of evidence-based lifestyle changes can simultaneously reduce the burden of fatty liver disease and lower the risk of kidney stone formation, making a combined approach both practical and efficient. Achieving and maintaining a healthy body weight is arguably the single most impactful step, as obesity drives insulin resistance, elevated urinary uric acid and oxalate, and hepatic fat accumulation. NICE NG49 notes that even a modest weight loss of 5 to 10 per cent of body weight can reduce liver fat measurably.^[14]

Dietary adjustments that benefit both conditions include:

• Reducing intake of ultra-processed foods, refined carbohydrates, and added sugars, which worsen insulin resistance and raise uric acid levels

• Limiting alcohol, which contributes to liver fat and raises urinary uric acid

• Eating a Mediterranean-style diet rich in vegetables, legumes, wholegrains, and unsaturated fats, which is associated with lower NAFLD severity and reduced stone risk

• Moderating animal protein intake, as high consumption raises urinary uric acid and calcium excretion

• Reducing salt intake, as a high-sodium diet increases urinary calcium excretion and raises stone risk

• Maintaining normal dietary calcium intake rather than restricting it, as low calcium intake can paradoxically increase oxalate absorption and stone risk

• Limiting high-oxalate foods (such as spinach, nuts, and chocolate) if you have a history of calcium oxalate stones, though this should be discussed with a dietitian rather than applied indiscriminately

Adequate hydration is particularly important for kidney stone prevention. NHS and urological guidance recommends drinking enough fluid to keep your urine a pale straw colour throughout the day, with a general aim of producing around 2 litres of urine daily, though individual needs vary. Water is the preferred fluid; sugar-sweetened drinks should be avoided.

Regular physical activity of at least 150 minutes of moderate-intensity exercise per week, in line with UK Chief Medical Officers' physical activity guidelines, improves insulin sensitivity, supports weight management, and benefits both liver and kidney health. If you are considering a structured weight management programme, Bolt Pharmacy is a GPhC-registered UK online pharmacy offering online weight-management consultations, with prescriber review and pharmacist support, where clinically appropriate options may be considered alongside lifestyle guidance.

Suspected side effects from any medicine can be reported to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk.

Scientific References

1. Bidirectional associations among gallstone disease, non-alcoholic fatty liver disease, kidney stone disease.
2. Insights from exploring the interrelated dynamics of gallstone disease, non-alcoholic fatty liver disease, and kidney stone disease.
3. Critical assessment of the reported bidirectional associations between gallstone, non-alcoholic fatty liver, and kidney stone diseases.
4. Non-alcoholic fatty liver disease (NAFLD).
5. The global, regional, and national burden of urolithiasis.
6. Type 4 renal tubular acidosis and uric acid nephrolithiasis: two faces of the same coin?.
7. Uric Acid Renal Lithiasis: New Concepts.
8. The management of patients with enteric hyperoxaluria.
9. Enteric hyperoxaluria: role of microbiota and antibiotics.
10. Kidney Stone Events and ESKD Incidence in Patients with Enteric Hyperoxaluria from Diverse Enteric Etiologies.
11. Obesity, Weight Gain, and the Risk of Kidney Stones.
12. Nephrolithiasis risk factors for obese patients on 24-hour urine collection metabolic evaluation.
13. Suspected cancer: recognition and referral (NG12).
14. Metabolic dysfunction-associated steatotic liver disease (MASLD) / Non-alcoholic fatty liver disease (NG49).
15. Medicines regulator approves up to 7.2 mg dose of semaglutide (Wegovy) for patients with obesity.
16. Semaglutide 2·4 mg once weekly in patients with non-alcoholic steatohepatitis (NEJM 2023).
17. MHRA authorises diabetes drug Mounjaro (tirzepatide) for weight management and weight loss.
18. Tirzepatide | Drugs | BNF.
19. Effect of tirzepatide versus insulin degludec on liver fat content (SURPASS-3 MRI substudy).
20. Liver Fat Changes in Patients With Type 2 Diabetes by Presence of Genetic Hepatic Steatosis: A Post Hoc Analysis of SURPASS-3 MRI.
21. Kidney stones.
22. UK Chief Medical Officers' physical activity guidelines.
23. Liver disease profiles, October 2022 update.

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