Most of us have heard about kidney stones and the pain they can cause, but not everyone knows exactly what they are, why some people get them, and how they are treated. A kidney stone can form when minerals build up in the urinary tract, creating crystals that consolidate into a pebble-like mass.
A kidney stone may be small and unnoticeable. But in some cases, it can grow to the size of a pea and become trapped in the ureter (the tube that drains urine from your kidneys down to your bladder), blocking urine flow and causing serious pain. In the worst cases, the pain is severe enough to prompt a trip to the emergency room, sometimes resulting in surgery.
One in 10 people will develop kidney stones at some point in their lives, and the number of cases has been gradually rising. Although kidney stones are more common in men than in women, anyone at any age can develop one.
Piruz Motamedinia, MD, a urologist and kidney stone specialist, says the rise in kidney stone diagnoses has mirrored increases in cases of obesity, diabetes, and high blood pressure. While kidney stones are very treatable, "the vast majority of patients don't know they have a kidney stone until they have symptoms, such as pain or bloody urine," says Dr. Motamedinia. "So, if you start noticing any symptoms, talk to your primary care physician right away."
Below, Dr. Motamedinia answered some common kidney stone questions.
1. How do kidney stones form?
Kidney stones are essentially small "rocks" made of minerals, such as calcium, and other ingredients that accumulate within the urinary tract.
"I like to use the analogy of the children's 'rock candy' experiment," Dr. Motamedinia says. "You add a cup of sugar to a cup of hot water to make a saturated syrup-type solution. As it cools, it crystallizes to form rock candy. With kidney stones, on the other hand, it's a saturated urinary solution that allows for the precipitation of the stone material."
Urine normally filters out excess salts, minerals, and waste products resulting from the metabolic processes of building proteins and breaking them down within the body, he explains. But when there is too much waste and not enough liquid to dilute it, crystals can develop and combine with other elements to form a stone.
"That's why drinking enough water and having a high urine output is so important," he says. "If you dilute your urine by drinking water or almost any other fluid, you are less likely to form a crystal or a stone. If your urine is dark yellow or orange, that's a sign you are dehydrated and need more fluids."
2. Are there different kinds of kidney stones?
Yes. There are four main types of kidney stones:
- Calcium stones, which include two subtypes: calcium oxalate and calcium phosphate stones. Calcium stones, especially calcium oxalate stones, are by far the most common type of kidney stone. Oxalate is a natural substance found in many foods, including spinach, beets, almonds, and soy products. When there is too much waste in the body and too little liquid to flush it out, it can combine with the calcium in the urine to form stones.
The calcium phosphate stone is what it sounds like—it combines calcium with phosphate, an electrolyte (or electrically charged mineral). While most people get more phosphate than they need from their diet, some of these stones are related to renal tubular acidosis, a metabolic condition that results when the kidneys aren't performing their function of removing acids from the blood into the urine.
- Uric acid stones can form when there is too much acid in the urine, which can result from eating too much fish, shellfish, poultry, pork, and meat (especially liver and other organ meats), which have high levels of purines, a common natural chemical compound. Too many purines can cause uric acid in the kidneys to crystallize and harden. Drinking enough water, cutting down on high-purine foods, and maintaining a healthy diet, in general, can help with avoiding uric acid stones.
- Struvite stones (also known as "infection stones") are associated with urinary tract infections (UTIs). Bacteria from the infection produces ammonia, which makes the urine more alkaline, leading to the formation of struvite—a combination of ammonium, magnesium, and phosphate. Struvite stones can form suddenly and quickly grow too large to pass. Surgery is often necessary to remove them.
- Cystine stones. A rare, inherited disease called cystinuria causes an amino acid (cysteine) to leak from the kidneys to the urine, where it may cause stones to form. Cystinuria is a lifelong condition and most people with it have recurring stones, so it's especially important for them to drink enough water, follow a recommended diet, and, in some cases, take medication to control the level of cysteine in their urine to prevent stones from forming. If a large stone forms, it may require surgical treatment.
3. How can you prevent kidney stones?
While each type of kidney stone is unique, there are recommendations that can help prevent any kind of kidney stone. The main one is hydration. Dr. Motamedinia recommends drinking eight to 10 glasses (about 64 to 80 ounces) of water a day. That can include coffee, tea, and juice but not dark cola drinks. While the reasons for avoiding dark cola are not completely clear, colas contain phosphoric acid, which is known to acidify urine and can help create certain kinds of kidney stones, Dr. Motamedinia explains. Instead, he suggests filling a measured container with water every morning and drinking it throughout the day "with specific goals in mind to achieve proper hydration."
A healthy diet can also help, and studies show the Dietary Approaches to Stop Hypertension (DASH) diet can reduce the risk of kidney stones. The DASH diet promotes vegetables, fruits, and whole grains, as well as limits full-fat dairy products, tropical oils, and fatty meats, which are more acidic.
Because calcium can block other substances in the digestive tract that cause stones, it helps to include calcium-rich foods in your diet, such as milk, cheese, yogurt, and leafy greens. It's also best to avoid excess salt, which can pull calcium out of the body and into the urine. If you are lactose intolerant, calcium-fortified soy and oat milk are good substitutes, he adds.
In terms of daily calcium, the recommended dietary calcium allowance for adults is 1,000 to 1,200 milligrams, depending on a person's age and sex. The National Institutes of Health (NIH) provides a chart for all age groups.
For salt intake, the U.S. Food and Drug Administration (FDA) recommends less than 2,300 milligrams of sodium per day. One strategy for reducing sodium intake is to read the labels on packaged and prepared foods, which often contain a surprising amount of salt, to help make sure you're staying within the recommended amount.
It may also help to know that certain conditions, including gout, obesity, and diabetes mellitus (a disease characterized by inadequate control of blood glucose levels—it includes type 1, type 2, gestational, and other types of diabetes), can put you at a higher risk for kidney stones. This is also true for certain medications, including diuretics and calcium-based antacids.
Another risk factor is a family history of kidney stones. "We're studying whether people with a family history have a genetic risk factor or if it's because people in certain families follow a similar diet that puts them at risk," Dr. Motamedinia says.
4. How are kidney stones diagnosed?
Many kidney stones are diagnosed when a person has symptoms, such as bloody urine, nausea and vomiting, pain, and an urgent need to urinate. They may go to the emergency room after a stone has become stuck at some point in its journey through the body, causing irritation, a backup of urine, and intense pain. "The passage of the stone, along with the blockage and swelling of the kidney, is what causes the pain; the stretching of the organ can result in severe pain and nausea," he says. "The pain can also come and go in waves as the ureter contracts to push the kidney stone through."
If a kidney stone is suspected, a CT scan or ultrasound can confirm it—a CT scan will also provide information on the size and shape of the stone.
Doctors can analyze the stones for their content, providing clues about the cause, which can be helpful in preventing future stones. Kidney stone recurrence is not uncommon; rates may be as high as 50% within five to seven years.
Not everyone with a kidney stone needs a specialist, but you may need a urologist if a stone is large or in a difficult location, or if there are multiple or recurring stones.
5. How are kidney stones treated?
The proper treatment for your kidney stone will depend on a range of factors, including its make-up, size, location, and the amount of pain you are experiencing. Below are four treatment approaches:
- Wait for the stone to pass. If the stone is small, it may pass without your experiencing any pain or knowing you had it. If you already know you have a stone—either because it was diagnosed after you reported symptoms or it was identified during imaging for another condition—a doctor can use imaging to measure it and determine how far it has moved along the urinary tract. "There are people who pass large stones without an issue, and there are people who have a really hard time passing smaller ones; it depends on the person's anatomy and pain tolerance," Dr. Motamedinia says. Taking over-the-counter pain medication as recommended and, occasionally, prescription medications that can dilate the urinary tract help to manage the pain and facilitate the passing of the stone, adds Dr. Motamedinia. "As always, maintaining hydration is imperative," he says.
- Shockwave lithotripsy. This is a common, noninvasive kidney stone treatment that uses a machine to administer sound wave energy from outside the body to crush the stone into pieces that can be passed. "Choosing the right stone and the right patient are important. A stone that is too large or too hard is not ideal. And, in certain cases, the patient's size, if they are pregnant, or if they use blood thinners may indicate the need for an alternative treatment," says Dr. Motamedinia. "However, in many cases, shockwave lithotripsy works quite well."
- Ureteroscopy. This is an endoscopic approach and the most commonly used method to remove kidney stones. A small, flexible camera is inserted into the urinary tract, where it is used to visualize the stone. The stone is broken into manageable pieces with a laser, and pieces are retrieved using a tiny basket—or they are turned into a fine powder that can be passed easily. The procedure can take 20 minutes to an hour and a half, depending on the size and location of the stone, among other factors. "The considerations mentioned above that would preclude the use of shockwave lithotripsy are less of a concern for ureteroscopy, making it a more versatile option," says Dr. Motamedinia.
- Percutaneous nephrolithotomy. Used for large stones unsuitable for other treatment options, this is a minimally invasive surgery performed through an incision in the back for direct access to the kidney. Instruments are inserted and used to pulverize the stone and suck it out. The procedure can take three hours.
Every kidney stone is different, Dr. Motamedinia explains. "Not all information will apply to every patient. Many of the restrictive diets you might see online, for instance, aren't backed up by evidence and usually don't apply to most patients," he says. "When in doubt, consult a urologist, even if it's just to make sure you're doing the right thing."
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To prevent uric acid stones, cut down on high-purine foods such as red meat, organ meats, and shellfish, and follow a healthy diet that contains mostly vegetables and fruits, whole grains, and low fat dairy products. Limit sugar-sweetened foods and drinks, especially those that contain high fructose corn syrup.What is the best preventative treatment for kidney stones? ›
The best way to prevent kidney stones is to make sure you drink plenty of water each day to avoid becoming dehydrated. To prevent stones returning, you should aim to drink up to 3 litres (5.2 pints) of fluid throughout the day, every day. You're advised to: drink water, but drinks like tea and coffee also count.How to drink apple cider vinegar to prevent kidney stones? ›
How much apple cider vinegar should I drink for kidney stones? Mix 2 tablespoons into 6 to 8 ounces of water for best results, and drink it all day.What are the worst foods for kidney stones? ›
Avoid stone-forming foods: Beets, chocolate, spinach, rhubarb, tea, and most nuts are rich in oxalate, which can contribute to kidney stones. If you suffer from stones, your doctor may advise you to avoid these foods or to consume them in smaller amounts.What foods help clear kidney stones? ›
- Drink plenty of fluids, particularly water.
- Eat less salt. ...
- Have only 2 or 3 servings a day of foods with a lot of calcium, such as milk, cheese, yogurt, oysters, and tofu.
- Eat lemons or oranges, or drink fresh lemonade. ...
- Limit how much protein you eat. ...
- Eat a low-fat diet.
Percutaneous Lithotripsy (PCNL) is the best treatment for large stones in the kidney. General anesthesia is needed to do a PCNL.Is there a natural way to eliminate kidney stones? ›
The absolute best kidney stone home remedy is simple: Drink more water. The liquid will help flush the stones through your urinary tract. Aim for at least 12 eight-ounce glasses of water per day if you're trying to pass a stone. If possible, catch the stone in a strainer when it passes.What is the fastest way to dissolve a kidney stone? ›
What Dissolves Kidney Stones Fast? Apple cider vinegar contains acetic acid which helps dissolve kidney stones. In addition to flushing out the kidneys, apple cider vinegar can also decrease any pain caused by the stones. In addition, water and lemon juice can help flush the stones and prevent future kidney stones.What is the fastest way to flush your kidneys? ›
- Drink more water. Drinking enough fluid every day is essential to a person's overall health. ...
- Reduce sodium intake. ...
- Make dietary changes.
Ingesting ACV before you go to sleep might help you wake up with stable blood sugar. A study published in the Diabetes Care journal found that taking vinegar at bedtime moderates glucose concentration when you wake up. Low potassium levels in the body can lead to muscle cramps.
Calcium Oxalate Stones: most common stones
Some examples of foods that have high levels of oxalate include peanuts, rhubarb, spinach, beets, Swiss chard, chocolate and sweet potatoes. Limiting intake of these foods may be beneficial for people who form calcium oxalate stones which is the leading type of kidney stone.
Eating foods rich in potassium helps prevent kidney stones from forming. Some foods that are high in potassium are bananas, cantaloupe, honeydew melon, orange juice and papaya.What are 5 foods to avoid for kidney stones? ›
Limit beef, pork, eggs, cheese, and fish, because they may raise your chances of most types of kidney stones. Vitamin C. Too much can make your body produce oxalate. So don't take more than 500 mg a day.What vitamin dissolves kidney stones? ›
Taking vitamin B6 with magnesium can inhibit oxalate stone formation. Both magnesium and vitamin B6 are used by the body to convert oxalate into other substances. Vitamin B6 deficiency leads to an increase in kidney stones as a result of elevated urinary oxalate.Does cranberry juice help kidney stones? ›
Cranberry juice has been thought to help with kidney stones, but research suggests that it may actually increase kidney stones formation — especially calcium oxalate stones, which are the most common kidney stones. Ideally, you should try to limit your juice intake to around one cup (236 mL) or less per day.What is the new treatment to dissolve kidney stones? ›
A new kidney stone treatment uses ultrasound to reposition and break up renal calculi in patients with minimal pain, no surgery and no anesthesia. University of Washington researchers are using ultrasound propulsion to move kidney stones for easier passage from the kidney through the ureter to the bladder.Is coffee bad for kidney stones? ›
The quartile analysis suggested that a per-quartile increment of caffeine intake was associated with a 6.28% increased risk of kidney stones.How do you flush a kidney stone in 24 hours? ›
A heating pad, hot water bottle, or warm bath can be effective. Drink plenty of water: Kidney stones need to be flushed out of the body so be sure to drink lots of water to keep them moving along. Minimize coffee, alcohol, tea, and soda.What are 3 treatments for kidney stones? ›
- Non-invasive extracorporeal shock wave lithotripsy (ESWL). ESWL involves the use of sound waves to crush the kidney stone into smaller pieces so they can more easily pass into the bladder.
- Percutaneous nephrolithotomy (PCNL). ...
- Ureteroscopy (URS). ...
Lemons contain citrate, which helps prevent calcium from building up and forming stones in your kidneys. Interestingly, the benefit doesn't seem to be present in oranges, making lemon a unique tool in kidney stone prevention.
So how does cranberry juice help? It can prevent bacteria from sticking to the walls of your kidneys, which helps prevent an infection from forming in the first place.What can I drink to repair my kidneys? ›
While plain water is the best drink for your kidneys, other fluids are perfectly acceptable, including coffee, green tea, low-potassium juices, and infused water. Avoid sweetened, carbonated beverages and coconut water.What vitamins flush kidneys? ›
The B-Vitamins Vital for Kidney Function
In addition to getting rid of waste, your kidneys also make red blood cells. Vitamin B-6, folate and vitamin B-12 all assist in the formation of blood cells. Eat grains, beans and fruit to make sure you're getting enough vitamin B-6 and folate.
- 01/9Caution! ...
- 02/9Consuming it in large doses. ...
- 03/9Brushing your teeth right after. ...
- 04/9Drinking it right after eating food. ...
- 05/9Avoid inhaling it. ...
- 06/9Don't forget to dilute it. ...
- 07/9Drinking it too much? ...
- 08/9Drinking it right before bed.
Low potassium levels in the blood (hypokalemia): Apple cider vinegar might lower potassium levels in the blood. If your potassium is already low, apple cider vinegar might make it too low. Don't use apple cider vinegar if you have this condition.What part of the day is best to drink apple cider vinegar? ›
Drinking apple cider vinegar before meals or right before bedtime may benefit your blood sugar levels the most. For example, one study in people with type 2 diabetes found that taking 2 tablespoons (30 ml) of apple cider vinegar at bedtime for 2 days reduced fasting blood sugar levels by up to 6% ( 7 ).What is the Mayo Clinic diet for kidney stones? ›
If you tend to form calcium oxalate stones, your doctor may recommend restricting foods rich in oxalates. These include rhubarb, beets, okra, spinach, Swiss chard, sweet potatoes, nuts, tea, chocolate, black pepper and soy products. Choose a diet low in salt and animal protein.Which fruit is best for kidney stone? ›
Citrus Fruits – Citrate, found in citrus fruits, helps block the formation of kidney stones and can help keep you safe from them. Examples of citrus fruits that you should include in your kidney stone diet are oranges, lemons, and grapefruit.Are eggs good for kidney stones? ›
Most animal sources of protein increase the level of uric acid and reduce the level of citrate in urine. Citrate is important in preventing stone formation. Therefore, you should avoid eating large quantities of red meat, poultry, chicken, pork, eggs and fish which contain large quantities of citrate.Is Quaker Oats good for kidney stones? ›
Rice and Oats – Rice and oats are also low in oxalates.
If you want to lower your risk of kidney stones developing, you can either cut down your oxalate levels or increase your calcium levels to bind the oxalate. Rice and oats can be part of a low oxalate diet.
Avoid eating berries that are rich in oxalates such as strawberry, raspberry, and blueberry. Although these fruits are healthy, they can increase the formation of kidney stones.Is Quaker Oats good for kidneys? ›
While oatmeal is higher in potassium and phosphorus than other hot cereals, it can still be part of a healthy kidney diet. A 1/2 cup serving of cooked oatmeal has 80 to 115 mg potassium and 90 to 130 mg phosphorus.Does peanut butter cause kidney stones? ›
A typical Southern diet easily lends itself to the formation of kidney stones. Eating and drinking large quantities of red meats, peanut butter, salt, coffee and tea puts susceptible people more at risk for developing kidney stones.Does lemon juice dissolve kidney stones? ›
Lemons contain citrate, which is a chemical that prevents calcium stones from forming. Citrate can also break up small stones, allowing them to pass more easily.How do you flush oxalates out of your body? ›
Drink enough water to help your body flush out excess oxalates. Get the recommended amount of calcium, which binds to oxalates during digestion. Limit sodium and sugar intake, which may contribute to kidney stones at high levels.Can vitamin D cause kidney stones? ›
Since vitamin D may increase kidney stone formation through an increase in urine calcium excretion, the evaluation of urinary calcium excretion after vitamin D supplementation is a major concern.What vitamins should I avoid if I am prone to kidney stones? ›
Vitamin C intake, also called ascorbic acid, has been proposed as a risk factor for kidney stones formation because vitamin C may increase urinary oxalate excretion, a type of calcium salt responsible for some stones.Can too much vitamin D cause kidney stones? ›
The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause nausea and vomiting, weakness, and frequent urination. Vitamin D toxicity might progress to bone pain and kidney problems, such as the formation of calcium stones.Are blueberries high in oxalates? ›
People who must follow a low oxalate diet may want to avoid eating blueberries. The oxalates in blueberries seem to block the absorption of calcium to some extent.Is pineapple juice good for kidney stones? ›
However, about whether pineapple juice can treat kidney stones, there is no scientific evidence to prove it, so it should be used with caution. The best way is still to drink pineapple juice and other fruit juices in moderation, which will help the body increase resistance and reduce as well as cure many diseases.
Years ago, the Merck Manual recommended 100–200 mg of vitamin B6 and 200 mg of magnesium per day for some kidney stone formers with elevated urinary oxalate. Most trials have shown that supplementing with magnesium and/or vitamin B6 significantly lowers the risk of forming kidney stones.What is new kidney stone treatment? ›
A new kidney stone treatment uses ultrasound to reposition and break up renal calculi in patients with minimal pain, no surgery and no anesthesia.Is coffee good or bad for kidney stones? ›
According to a 2021 study through the National Kidney Foundation, caffeine, whether in tea, soda, coffee, or alcohol, is protective and may decrease the risk of kidney stones. Even going from drinking 1 cup to 1.5 cups a day may reduce the odds of potential kidney stones by up to 40%.Is there something you can take daily to prevent kidney stones? ›
These include hydrochlorothiazide, chlorthalidone, or indapamide, all of which help to prevent kidney stones from returning, especially in people who have high levels of calcium in the urine.
- Staying hydrated is key. ...
- Water. ...
- Lemon juice. ...
- Basil juice. ...
- Apple cider vinegar. ...
- Celery juice. ...
- Pomegranate juice. ...
- Kidney bean broth.
Ammonius of Alexandria (276 BC) was the first person to suggest crushing the stone to facilitate its removal . He stabilized the stone with a hook and then split the stone using a thin blunt-ended instrument.