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Kidney Stone Disease (Nephrolithiasis)​

Written by: Apprentice Dietitian Chang Chiao Wei

What is a kidney stone?

A kidney stone is a hard deposit formed in the kidneys when certain minerals, like calcium, oxalate, and uric acid, bind together and crystallize due to high concentration in the urine. These stones can vary in size, from tiny grains to larger stones that block the urinary tract, causing severe pain.

Types and Prevalence

Kidney stones are categorized into four main types:

  • Calcium Oxalate & Calcium Phosphate (70-80%) – The most common type.
  • Uric Acid Stones (10%) – Formed due to excessive uric acid.
  • Struvite Stones (10%) – Linked to urinary tract infections (UTIs).
  • Cystine Stones (<1%) – Caused by a genetic disorder.

Historically, kidney stones were more common in men, but the gender gap is narrowing as more women are being diagnosed. Prevalence rates vary across regions, with 10-20% in Asia and 15-18% in Western countries.

Signs and Symptoms

Common symptoms include:

  • Severe pain in the back, side, lower abdomen, or groin.
  • Burning or painful urination.
  • Cloudy, foul-smelling, pink, red, or brown-colored urine.
  • Nausea, vomiting, fever, or chills (in severe cases).

Small kidney stones may pass on their own, causing mild or no symptoms, but larger stones may block the urinary tract and require medical attention. Pain relievers or surgery may be necessary depending on the size and location of the stone.

Dietary Management

Diet plays a crucial role in preventing and managing kidney stones. Here’s a breakdown of essential nutrients and guidelines:

Nutrient Recommended Intake
Sodium
Less than 2,300 mg/day
Calcium
800 – 1200 mg/day
Oxalate
40 – 50 mg/day
Protein
0.8 – 1.4 g/kg of body weight
Fluids
More than 2.5 L/day
Vitamin C
Less than 1000 mg/day

Dietary Tips for Prevention

1. Reduce Sodium Intake

  • Limit salt intake to less than 1 teaspoon (6g) daily.
  • Replace salt with herbs and spices (e.g., garlic, ginger, cumin, turmeric).
  • Avoid high-sodium foods like canned foods, fast food, sausages, and processed meats.

2. Control Oxalate Intake

  • Limit consumption of oxalate-rich foods like spinach, sweet potatoes, beetroot, rhubarb, nuts, chocolate, and soy.
  • Pair oxalate-rich foods with calcium-rich foods (e.g., chocolate + milk or peanuts + yogurt) to reduce oxalate absorption.

3. Get Adequate Calcium Intake

  • Contrary to popular belief, reducing calcium does not prevent kidney stones. In fact, adequate calcium intake helps bind oxalate in the intestines, preventing its absorption.
  • Include both dairy (milk, cheese, yogurt) and non-dairy (chia seeds, kale, broccoli) sources of calcium in your diet.
  • Choose calcium-rich foods with low sodium or added sugar.

4. Moderate Protein Intake

  • Limit animal proteins (red meat, organ meat, seafood) as they increase uric acid production, making urine more acidic, which promotes kidney stone formation.
  • Opt for plant-based proteins (lentils, beans, peas) to avoid acidic urine.

5. Increase Fluid Intake

  • Aim to drink at least 2.5L of water daily to dilute urine and prevent stone formation.
  • Add lemon juice to water as citric acid may prevent stone formation.
  • Avoid sugary drinks and sodas.

6. Avoid Excessive Vitamin C

  • High doses of vitamin C supplements can increase oxalate production, raising the risk of stones.
  • It’s better to consume vitamin C from fruits and vegetables rather than high-dose supplements.

Dietary Tips for Other Types of Kidney Stones

  • Calcium Stones: Reduce sodium, oxalate, and excessive vitamin C; maintain adequate calcium intake, moderate protein, and sufficient hydration.
  • Uric Acid Stones: Limit purine-rich foods (red meat, organ meat, seafood) and alcohol; stay hydrated.
  • Struvite Stones: Typically caused by UTIs and require medical or surgical intervention.
  • Cystine Stones: Caused by a genetic disorder and also require medical treatment.

Take-Home Message

Dietary changes, such as reducing sodium, controlling oxalate, and ensuring adequate hydration, can help prevent kidney stones. While dietary changes can manage calcium and uric acid stones, struvite and cystine stones may require medical treatment. Caring for kidney health is essential, as the kidneys play a vital role in filtering blood and removing waste.

Reference List

  1. Han, H., Segal, A. M., Seifter, J. L., & Dwyer, J. T. (2015, July). Nutritional management of kidney stones (nephrolithiasis). Clinical nutrition research. Retrieved February 8, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4525130/  
  2. U.S. Department of Health and Human Services. (n.d.). Definition & Facts for Kidney Stones. National Institute of Diabetes and Digestive and Kidney Diseases. Retrieved February 8, 2023, from https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-stones/definition-facts
  3. Gillams, K., Juliebø-Jones, P., Juliebø, S. Ø., & Somani, B. K. (2021, October 8). Gender differences in kidney stone disease (KSD): Findings from a systematic review. Current urology reports. Retrieved February 8, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8497339/
  4. Dottie. (2016, April 7). Urinary stones. PORTAL MyHEALTH. Retrieved February 8, 2023, from http://www.myhealth.gov.my/en/urinary-stones/ 
  5. Kidney stones: Diet plan and prevention. National Kidney Foundation. (2022, November 4). Retrieved February 8, 2023, from https://www.kidney.org/atoz/content/diet#:~:text=To%20prevent%20uric%20acid%20stones,and%20low%2Dfat%20dairy%20products 
  6. Mitchell, T., Kumar, P., Reddy, T., Wood, K. D., Knight, J., Assimos, D. G., & Holmes, R. P. (2019, March 1). Dietary oxalate and Kidney Stone Formation. American journal of physiology. Renal physiology. Retrieved February 8, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6459305/ 
  7. Diet and Kidney Stones – Queensland Health. (n.d.). Retrieved February 24, 2023, from https://www.health.qld.gov.au/__data/assets/pdf_file/0024/151863/renal_kdnystones.pdf  
  8. NHS. (n.d.). Prevention of Kidney Stones. NHS choices. Retrieved February 8, 2023, from https://www.nhs.uk/conditions/kidney-stones/prevention/#:~:text=The%20best%20way%20to%20prevent,throughout%20the%20day%2C%20every%20day.   
  9. Pearle MS;Goldfarb DS;Assimos DG;Curhan G;Denu-Ciocca CJ;Matlaga BR;Monga M;Penniston KL;Preminger GM;Turk TM;White JR; ; (n.d.). Medical Management of Kidney Stones: AUA guideline. The Journal of urology. Retrieved February 8, 2023, from https://pubmed.ncbi.nlm.nih.gov/24857648/ 
  10. Gul, Z., & Monga, M. (2014, November 28). Medical and dietary therapy for Kidney Stone Prevention. Korean Journal of Urology. Retrieved February 8, 2023, from https://synapse.koreamed.org/articles/1006212