Kidney stones are a common and painful health issue affecting millions globally. These hard mineral deposits form in the kidneys and can cause sharp pain, urinary issues, and in severe cases, long-term kidney damage. While genetics, medical history, and hydration status contribute to risk, diet plays one of the most significant roles, both in stone formation and prevention.According to Healthline, understanding what you eat can help reduce the risk of recurrence and even prevent kidney stones from forming in the first place. This article dives into how stones form, the major types, and which 10 foods may increase or reduce your risk.
What are kidney stones
Kidney stones (renal calculi) are solid crystals that form from substances in the urine, such as calcium, oxalate, and uric acid. When the concentration of these substances becomes too high and there isn’t enough fluid to dilute them, they can crystallise and gradually grow into stones.These stones can remain in the kidneys or travel through the urinary tract. If large enough, they may block urine flow, causing intense pain, blood in the urine, and infection.
Common types of kidney stones
- Calcium oxalate stones – The most common type, caused by high levels of calcium and oxalates in urine.
Uric acid stones – Often linked to high purine intake from red meat and organ meats.- Struvite stones – Usually develop after urinary tract infections.
- Calcium phosphate stones – Related to high urinary pH and certain metabolic disorders.
- Cystine stones – A rare genetic condition where too much cystine leaks into urine.
How are kidney stones formed?
Kidney stones form through a process called crystallisation. When urine becomes concentrated due to low fluid intake, and contains excess minerals like calcium, oxalate, or uric acid, these can stick together and form crystals. If the urine lacks protective compounds like citrate (which prevents crystal formation), these tiny crystals can grow into stones.Symptoms may include:
- Sharp pain in the lower back or abdomen
- Nausea and vomiting
- Blood in the urine
- Painful or frequent urination
10 foods that can trigger kidney stones
- Spinach: According to Healthline, spinach contains high levels of oxalates, which can bind with calcium to form calcium oxalate stones — the most common type.
Spinach
- Beets: As Regency Healthcare explains, beets are also rich in oxalates and may raise stone risk when eaten frequently.
- Nuts and nut butters: Nuts like almonds, peanuts, and cashews are healthy fats but are high in oxalates, especially problematic for individuals already prone to stones.
- Chocolate: Chocolate and cocoa products, especially dark chocolate, contain oxalates and should be consumed in moderation.
Chocolate
- Black tea: According to Gleneagles Hospitals, black tea is a leading source of dietary oxalates. Excessive consumption — especially in hot climates — can lead to a buildup in the kidneys.
- Red meat: High in purines, red meat can increase uric acid levels, which may lead to uric acid stones.
Red Meat
- Salt (Sodium): A high-sodium diet causes the kidneys to excrete more calcium in urine, a known contributor to calcium-based stone formation.
- Cola drinks: Dark sodas contain phosphoric acid, which may acidify urine and increase kidney stone risk.
- Processed and packaged foods: Instant soups, chips, and packaged snacks are often high in both sodium and preservatives, straining kidney function.
- Rhubarb: Although healthy in moderation, rhubarb is extremely high in oxalates and is on the avoid list for stone-formers.
Rhubarb
10 foods that help prevent kidney stones
- Water: The number one preventive strategy. According to Healthline, drinking 2–3 litres daily dilutes minerals in urine, making crystal formation less likely.
Water
- Citrus fruits (lemon, lime, orange): Citrus fruits are rich in citrate, which binds to calcium in the urine, reducing the risk of calcium oxalate stones.
- Calcium-rich foods (like milk, yoghurt, cheese): Unlike calcium supplements, which may increase risk, dietary calcium helps bind to oxalates in the gut, preventing their absorption.
Yoghurt
- Bananas: Low in oxalates and rich in potassium, bananas help maintain a healthy electrolyte balance and reduce stone recurrence.
Banana
- Barley water: Traditional Indian home remedy. As Gleneagles Hospitals note, barley water helps increase urine output and may dissolve small crystals.
- Cucumbers: Hydrating and low in oxalates, cucumbers are ideal for keeping urine diluted and preventing stone growth.
Cucumber
- Whole grains: Oats, brown rice, and barley provide magnesium, which may inhibit crystal formation.
- Basil leaves: Used in Ayurveda, basil may reduce uric acid levels and support kidney detoxification.
Basil leaves
- Watermelon: High in water and potassium, watermelon helps flush the kidneys and supports a healthy urinary system.
- Pomegranate: Rich in antioxidants and potassium, pomegranates are thought to improve kidney function and reduce stone recurrence.
Pomegranate
Additional prevention tips for kidney stones
- Limit vitamin C supplements, as excess is converted to oxalates
- Eat calcium-rich foods instead of relying on supplements
- Avoid excessive animal protein, which raises uric acid
- Stay physically active to maintain healthy kidney function
- Check urine pH levels, especially if you’ve had stones before
When to seek medical help
If you experience:
- Severe back or abdominal pain
- Bloody or cloudy urine
- Fever or chills
- Vomiting or nausea with pain
Consult a healthcare provider immediately. Imaging tests like ultrasound or CT scans can confirm the diagnosis, and treatments range from hydration and medication to procedures like shockwave lithotripsy or ureteroscopy.
