腎臓結石の予防と管理：結石知らずでいるための最新ガイド

最終更新日： 2026年6月14日

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Kidney stones are one of the most common urological conditions I see in my practice — and one of the most preventable. As a board-certified urologist specializing in kidney stone treatment, I want to share with you a comprehensive, patient-friendly overview of how stones form, how to prevent them through diet, and how modern non-invasive treatments like ESWL have transformed care.

This article is drawn from my presentation originally delivered at the Royal Phnom Penh Urology Seminar on June 29, 2019. Although several years have passed, the fundamental principles of urolithiasis management and the technological shifts in treatment remain highly relevant for patients today.

The Balance of Salts

Kidney stones are fundamentally about a disruption in the balance of salts within the urinary tract. To understand stone formation, imagine a salt farm: sea water is let in, it dries, the water vaporizes, and sea salt remains. Similarly, kidney stones develop when urine becomes “supersaturated” with insoluble compounds. When these compounds can no longer remain dissolved, they precipitate and form crystals.

誰がリスクにありますか？

• Gender and Age: The peak age for stone formation is in males between 20–30 years old.
• Lifetime Prevalence: Approximately 12% of men and 7% of women will experience kidney stones in their lifetime.
• Comorbidities: Stone formation is frequently related to obesity, hypertension, and diabetes.
• Genetics: A family history of kidney stones can increase your risk by up to 2.5 times.

Why Do Stones Form?

Supersaturation occurs primarily due to two factors: dehydration and genetic predispositions that cause the over-excretion of ions in the urine. The “insoluble compounds” that act as the building blocks for these stones include calcium, oxalate, phosphate, magnesium, and uric acid.

While there are hundreds of types of stones, they are often mixtures of these substances. The four most common types are:

1. Calcium Oxalate (75%): The most prevalent variety.
2. Struvite (10–20%): Often associated with infections.
3. Uric Acid (5–15%): Linked to acidic urine and high-protein diets.
4. Calcium Phosphate (5%).

The Pillar of Prevention: Dietary Control

The “magic words” for kidney stone prevention are Balance, Balance, and Balance. Adjusting your intake of specific nutrients can significantly lower the risk of recurrence.

Fluid Intake — The Most Important Factor

Dehydration is the most important and easiest factor that we can correct. The recommendation: drink more than 2.5 liters of oral fluids daily, and avoid excessively hot environments that cause heavy sweating and fluid loss.

Calcium — The Common Misconception

Many patients believe they should stop eating calcium to prevent calcium stones. This is a mistake — low calcium intake is not recommended.

• The Goal: Aim for 800 mg/day to 1,200 mg/day.
• Why? A study showed that a moderate calcium intake (1,200 mg/day) plus a low animal protein diet resulted in a 51% lower incidence of stones compared to a low-calcium diet of 400 mg/day.
• Pro Tip: Calcium supplements should be taken during meals because the calcium will bind to oxalate in the gut and prevent its absorption into the body.

Oxalate Management

Since calcium oxalate stones account for 75% of cases, managing oxalate is vital. Aim for 40–50 mg/day. High-oxalate foods to limit include dark chocolate, cocoa powder, spinach, rhubarb, nuts, seeds, black tea, and tofu.

Sodium and Protein

• Sodium: Consuming too much sodium causes more calcium to be excreted in the urine. Limit sodium to 2,000–3,000 mg/day.
• Protein: High-protein diets (>2 g/kg/day) can make urine acidic, resulting in uric acid stones and increased calcium in the urine. Aim for a moderate intake of 0.8–1.4 g/kg/day. Interestingly, research indicates there is no significant difference in stone risk between animal and plant proteins.

ビタミンC

While Vitamin C is healthy, excessive amounts can be metabolized into dehydroascorbic acid and then converted to oxalate. Consuming more than 1,000 mg/day is associated with a 40% higher risk of kidney stones.

Citrate: Our Stone-Fighting Hero

Citrate is known as a stone inhibitor. It prevents stone-forming activity and increases urine pH, which creates an environment where uric acid crystals are less likely to form.

• Natural Sources: Citrus fruits like lemon and lime. Drinking 4 ounces of pure lemon juice または 32 ounces of prepared lemonade daily can provide a similar amount of citric acid as pharmacological therapy.
• Medical Citrate: Potassium citrate (available in powder or tablet form) is the “gold standard” for treating uric acid stones and can even help dissolve them.

Modern Treatment: 4th-Generation ESWL

When prevention fails, technology provides non-invasive solutions. 体外衝撃波結石破砕術 uses focused shock waves to break stones into small fragments that can be passed naturally in the urine. For a deeper look at how this technology evolved from a wartime observation to a 4th-generation tracking system, see my earlier article on the evolution of ESWL.

Comparing the older 3rd-generation machines to today’s 4th-generation ESWL highlights significant patient benefits:

Feature	3rd Generation	4th Generation
Radiation	Unnecessary X-ray exposure	Near-zero radiation (ultrasound)
Anesthesia	Often required due to pain	No anesthesia or painkillers needed
Accuracy	Shockwaves can miss the target	Auto ultrasound tracking system
Recovery	Requires hospitalization	Daycare / outpatient, same-day discharge

Evidence of Effectiveness

Scientific literature supports the move to 4th-generation technology:

• Accuracy: A study of the Lite-Med 9200 lithotripter reported a 94.3% hit rate with the tracking system, compared to only 68.6% without tracking.
• Human Success: A clinical study of 1,332 patients using this modern technology reported an 80% stone-free rate at 3-month follow-up.
• Safety: Major complications, such as renal hematomas, were not reported in these modern trials.

Addressing the Cost-Effectiveness

A common question is whether modern ESWL is “too expensive.” This is often a misunderstanding based on data from Western countries.

• In the West: ESWL has historically been expensive because older 3rd-generation machines are painful, requiring an operating room, general anesthesia, anesthesia professional fees, and overnight hospital stays — all of which add up.
• In our modern practice: Because 4th-generation technology is virtually painless and far more accurate, we eliminate the costs of anesthesia and hospitalization entirely.

Furthermore, standard research often cites success rates based on lower shockwave counts (around 3,000 pulses per session). In our current practice, we may fire up to 6,000 shockwave pulses at higher power (up to 18 kV) because the patient can tolerate it without pain medication. This significantly increases the efficacy of a single session and reduces the need for retreatment.

Take-Home Messages & Dietary Reference

• Commonality: Kidney stones are a frequent disease, but they are highly manageable.
• Diet is key: Focus on a balanced diet — don’t cut out calcium, but do cut back on salt and high-oxalate foods.
• Hydration: Drink more than 2.5 liters of water every single day.
• Treatment: Modern technology allows us to manage stones effectively without surgery or wounds.
• Consultation: If you have a stone smaller than 2 cm, ESWL is highly recommended by the European Association of Urology (EAU).

Nutrient	Recommended Intake
Calcium (Ca)	800–1,200 mg/day
Oxalate	40–50 mg/day
Sodium (Na)	2,000–3,000 mg/day
Protein	0.8–1.4 g/kg/day
Fluids	> 2.5 Liters/day
ビタミンC	Dietary Reference Intake (avoid > 1,000 mg/day)

If you are dealing with kidney stones or want a personalized prevention plan based on your stone composition and metabolic profile, Dr. Soarawee Weerasopone offers specialist consultations in kidney stone treatment at Bangkok Hospital Headquarters. 診療をご予約.

Frequently Asked Questions About Kidney Stone Prevention

腎臓結石を予防するには、どのくらいの水を飲めばよいですか？

The recommended fluid intake for kidney stone prevention is more than 2.5 liters per day. In hot climates or for people who sweat heavily, even more may be needed to maintain dilute urine and prevent supersaturation.

カルシウム結石がある場合、カルシウムは避けるべきですか？

No — this is a common misconception. Low calcium intake is not recommended and may actually increase stone risk. A moderate intake of 800–1,200 mg per day, ideally with meals, allows calcium to bind oxalate in the gut and reduce stone formation.

レモン汁は本当に腎臓結石の予防に役立ちますか？

Yes. Lemon and lime juice are rich in citrate, a natural stone inhibitor. Drinking 4 ounces of pure lemon juice or 32 ounces of prepared lemonade daily can provide a similar amount of citric acid to pharmacological therapy.

ESWL（体外衝撃波結石破砕術）は、一般的に**2cm未満**の結石の治療に最も効果的とされています。 ただし、これはあくまで目安であり、結石の場所、硬さ、数、患者さんの状態などによって最適な治療法は異なります。2cm以上の結石でもESWLで治療可能な場合もありますし、小さい結石でもESWL以外の治療法が選択されることもあります。 最終的な治療法の選択は、専門医による診察によって決定されます。

According to European Association of Urology (EAU) guidelines, ESWL is highly recommended for kidney stones smaller than 2 cm. Stones under 1 cm have the highest single-session success rates with modern 4th-generation technology.

Is modern ESWL really as expensive as it sounds?

Cost-effectiveness studies often reflect older 3rd-generation machines that require general anesthesia and hospital admission. Modern 4th-generation ESWL is painless, performed as a daycare procedure, and eliminates the costs of anesthesia and hospitalization, making it significantly more affordable than Western literature suggests.

免責事項：本コンテンツは、バンコク病院本院の認定泌尿器科専門医であるソアラウィー・ウィーラソポーン医師によって執筆・監修されたものです。本コンテンツはあくまで教育目的であり、医学的アドバイスを構成するものではありません。いかなる治療を開始する前にも、必ず資格を有する医療専門家に相談してください。.