Kidney Stone Prevention Diet: Foods to Eat and Avoid

What is a Kidney Stone?

A kidney stone is a hard, crystalline deposit that forms in the kidney or urinary tract. They can range in size from a grain of sand to a golf ball and can cause severe pain when passing through the urinary system. Kidney stones can be caused by a variety of factors, including dehydration, diet, and genetics.

Types of Kidney Stones

Not all kidney stones are the same. Kidney stones can vary in size, shape, composition and location in the urinary tract. The most common type of kidney stone is made of calcium oxalate, but there are also uric acid, struvite and cystine stones. The type of kidney stone someone has can depend on a variety of factors, including their diet, genetics, medical history and medications they are taking.

What is the most important factor to prevent kidney stone formation?

The most important factor to prevent kidney stone formation is adequate hydration. Drinking enough water and fluids throughout the day can help prevent kidney stones from forming by flushing out the urinary system and diluting the concentration of minerals and other substances that can contribute to stone formation. It is generally recommended to drink at least eight cups of water per day, but individual needs may vary depending on factors such as activity level and climate. Additionally, a balanced diet that is low in sodium and animal protein and high in fruits, vegetables, and whole grains can help reduce the risk of developing kidney stones. 

Kidney Stone Diet Recommendations

Following a kidney stone diet can help reduce the risk of developing new kidney stones. The diet typically includes drinking plenty of water and fluids throughout the day and limiting the intake of foods and beverages that can contribute to stone formation, such as animal protein, sodium, and oxalate-rich foods like spinach, chocolate, and nuts. In addition, the diet may recommend increasing the intake of fruits and vegetables, which are rich in potassium and citrate, substances that can help prevent stone formation. Depending on the type of kidney stone, specific dietary recommendations may vary, and it is important to consult with a urology specialist or registered dietitian to develop an individualized plan.

Kidney Stone Types

1. Calcium oxalate stones: Most common stones

Calcium oxalate stones are the most common type of kidney stone, accounting for around 75-80% of all cases. These stones form when calcium combines with oxalate in the urine, creating a hard crystalline structure that can range in size from a grain of sand to a golf ball. Oxalate is a naturally occurring substance found in many foods, including leafy green vegetables, chocolate, and nuts. People who are prone to developing calcium oxalate stones may benefit from limiting their intake of these foods, as well as reducing their sodium and animal protein intake.

2. Uric acid stones: Another common stone

Uric acid stones are another common type of kidney stone, accounting for around 5-10% of cases. These stones form when there is too much uric acid in the urine, which can be caused by a variety of factors, including gout, certain medications, and a diet high in purines (substances found in animal protein). Uric acid stones can often be prevented by making dietary changes, such as reducing the intake of high-purine foods like red meat and seafood and increasing the intake of fluids to help flush out the urinary system. In some cases, medications may be prescribed to help prevent the formation of new stones.

Will it help or hurt to take a vitamin or mineral supplement?

Whether taking a vitamin or mineral supplement will help or hurt in preventing kidney stones depends on the individual's health status and the type of stone they have. Some supplements, such as vitamin C and calcium, can increase the risk of stone formation if taken in excess, while others like magnesium may help reduce the risk. It is important to consult with a healthcare provider or registered dietitian before taking any supplements to determine if they are appropriate for the individual's needs.

Kidney Stone Diet Plan: Diet recommendations for kidney stones

Following a kidney stone diet can help reduce the risk of stone formation. Here are some diet recommendations:

1. Drink plenty of fluid: 2-3 quarts/day

• Staying hydrated is important for preventing kidney stones. Drinking 2-3 quarts (8-12 cups) of fluid per day can help flush out minerals and prevent them from forming stones.
• Water is the best fluid to drink, but other options include lemonade, orange juice, and herbal tea.
• Avoid drinks with high levels of sugar and caffeine, as they can increase the risk of developing stones.

2. Eat enough dietary calcium

• Adequate calcium intake is important for reducing the risk of kidney stone formation.
• The recommended daily intake of calcium is 1,000-1,200 milligrams for most adults.
• Good sources of calcium include dairy products, leafy green vegetables, and calcium-fortified foods.
• Low-calcium diets can increase the risk of kidney stone formation by causing the body to absorb more oxalate, a substance that can contribute to stone formation.

3. Avoid extra calcium supplements

• When it comes to preventing kidney stones, it's important to get enough calcium in the diet. However, taking extra calcium supplements may increase the risk of stone formation. 
• Studies have shown that high doses of calcium supplements can bind with other substances in the urine, leading to crystal formation.
• It's important to talk to a healthcare professional before starting any new supplement regimen, especially if one has a history of kidney stones.

4. Eat a moderate amount of protein

• Consuming too much protein can increase the risk of developing kidney stones.
• A moderate amount of protein is necessary for maintaining muscle mass and promoting overall health.
• The recommended daily intake of protein for the average adult is about 0.8 grams per kilogram of body weight.
• Animal-based sources of protein, such as meat and dairy products, contain high amounts of purines, which can increase the risk of kidney stones.

5. Avoid high salt intake

• An increase in the sodium levels within the body increases calcium levels, which in turn reduces the citrate in the urine and increases the likelihood of forming stones.
• The recommended daily intake of salt is no more than 2,300 milligrams (mg) per day or about one teaspoon.
• Processed and packaged foods are often high in salt, so it's important to read food labels and choose low-sodium options whenever possible.

6. Avoid high doses of vitamin C supplements

• Vitamin C is an important nutrient that helps support a healthy immune system, wound healing, and skin health.
• However, taking high doses of vitamin C supplements can increase the risk of developing kidney stones.
• The recommended daily intake of vitamin C for adults is 75-90 mg per day for women and men, respectively.
• It's generally safe to consume vitamin C through food sources, but supplements can provide much higher doses.

7. Eat more fresh, non-processed foods, like fruits and vegetables, fresh meats

• A kidney stone diet should be rich in fresh, non-processed foods like fruits, vegetables, and fresh meats as they can help prevent kidney stones.
• These foods are typically low in sodium and high in important nutrients like fibre, vitamins, and minerals.
• Fruits and vegetables are also high in water content, which can help keep the kidneys flushed and prevent the formation of stones.

8. In general, limit the intake of meat

• Animal-based sources of protein, like meat and dairy, can be high in purines, which can increase the risk of developing kidney stones.
• High-protein diets can also put a strain on the kidneys and increase the risk of kidney damage over time.
• Eating plant-based sources of protein, like beans, lentils, and tofu can be a healthier alternative. They are generally lower in purines and can also provide important nutrients like fiber and antioxidants.

9. Increase the intake of citrus fruits and juices

• Citrus fruits like oranges, lemons, and grapefruits are high in citrate, which can help prevent the formation of kidney stones.
• Citrate works by binding to calcium in the urine, preventing it from forming crystals that can lead to stones.
• Drinking citrus juices, like orange juice or lemonade, can also be a good way to increase citrate intake.

10. Decrease the amounts of foods that are high in a substance called oxalate

• Oxalate is a substance found in many foods that can increase the risk of developing kidney stones.
• High oxalate foods include spinach, rhubarb, beets, nuts, chocolate, tea, and certain fruits like raspberries and kiwifruit.
• While these foods are generally healthy, it's important to consume them in moderation if one has a history of kidney stones or is at risk for developing them.