Kidney stones or renal calculi are hard deposits made of crystals inside of the kidneys that are formed from different types of minerals and salts that concentrate in the urine. Over several weeks or months, these crystals can concentrate and develop into stones. When kidney stones develop, this is a condition known as nephrolithiasis or urolithiasis.
When kidney stones are present and begin to move through the urinary tract, they cause pain in the back or side, blood in the urine, and nausea/vomiting. While kidney stones can be very painful to pass, they do not usually cause permanent damage if they're recognized promptly. Occasionally, kidney stones can become lodged in the urinary tract and lead to complications such as urinary tract infections and damage to the kidneys.
Kidney stones are one of the most common urinary tract disorders and can develop in otherwise "healthy" people. Around 12% of the world's population overall experience kidney stones at some point in their lives, and the rates are increasing. Men are more frequently impacted than women, and those with high blood pressure, diabetes, and obesity are at an increased risk. Once someone develops a stone, they are far more likely to develop another stone in the future.
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What are Kidney Stones?
Urolithiasis is a condition where stones form anywhere inside the urinary tract, from the kidneys to the urethra. Kidney stones are hard irregularly-shaped pebble-like collections of crystals. These crystals are made up of minerals and salts that concentrate in the urine. They range in size from as small as a grain of sand up to the size of a golf ball.
The kidneys normally remove waste from the blood and excrete it from the body by dissolving it in the urine. When there is too high of a concentration of certain minerals and salts such as calcium, oxalate, urate, cystine, xanthine, and phosphate in the urine relative to too little liquid, crystals begin to form. The crystals attract other elements and join together to form a solid that grows larger unless it is passed out of the body with the urine or the growth is halted by other substances.
There are four main types of kidney stones: calcium oxalate, uric acid, struvite, and cystine.
Calcium oxalate stones are the most common type of kidney stones and form when calcium and oxalate combine in the urine. These stones are more likely when the urine contains high quantities of calcium or oxalate and/or not enough fluid. Too much calcium can occur in the urine from absorbing too much calcium from the diet, reabsorbing calcium from the bones, or having issues regulating how much calcium the kidneys excrete.
Oxalates are absorbed through the diet from eating large amounts of beets, potatoes, peanuts, coffee, chocolate, spinach, rhubarb, beans, dark beer, and other high-oxalate foods. They are also made daily by the liver, in a process that increases with the consumption of ascorbic acid or high doses of vitamin D. Oxalates may be increased in inflammatory bowel disease or as a consequence of prior intestinal surgery or an imbalanced microbiome. Calcium stones can also be composed of calcium phosphate.
Kidney stones that are composed of struvite, a mixture of magnesium, ammonium, phosphate, and calcium carbonate, form when there are certain types of urinary tract infections. Bacteria that can infect the upper urinary tract produce ammonia, making the urine less acidic (or more alkaline). Struvite stones form when the urine becomes more alkaline, which favors crystal formation. They can grow quickly and become very large.
Uric acid stones form when too much purine concentrates in the urine. Consuming high amounts of purines in foods such as beef, poultry, pork, fish, organ meats like liver, and shellfish leads to a higher production of monosodium urate. When urate builds up in the urine due to high protein consumption, dehydration or fluid loss from diarrhea or malabsorption, genetic factors, and/or metabolic factors in those with diabetes or metabolic syndrome, uric acid stones can form.
Cystine is an amino acid that can accumulate in people with a hereditary disorder called cystinuria, which causes the kidneys to excrete too much of this substance. Cystine stones form when cystine crystals concentrate and form stones in the urine. Since these stones are due to a genetic disorder, they tend to recur and are typically larger than other kidney stones.
Kidney Stones Symptoms
Once stones form in the kidneys, they may stay lodged there or travel down the urinary tract with the urine through the ureter or tube that connects the kidney to the urethra from which urine is expelled. Very small stones may sometimes move out of the body in the urine without causing too much pain. But larger stones and those that don't move through completely can cause a blockage that leads to a back-up of urine in the kidney, ureter, bladder, or urethra that causes swelling, spasms, and pain.
Common symptoms of kidney stones include:
- severe spastic pain (renal colic) in the lower back
- pink, brown, or red urine from blood in the urine
- an increased urge to urinate or urinating more often than usual and/or in frequent small amounts
- nausea and vomiting
- fever and chills
- urine that smells bad
- cloudy urine
The pain that occurs with kidney stones is usually severe and sharp, focused in the side and back below the ribs, and may radiate to the lower abdomen and groin. Due to spasms, this pain may come in waves and fluctuate in intensity. It can also move around as the stone passes through the urinary tract. There may also be burning or pain while urinating.
What Causes Kidney Stones?
Many factors contribute to the formation of kidney stones. These stones form when the urine becomes more concentrated. This occurs when there is not enough water to dilute the crystal-forming substances such as calcium, oxalate, and uric acid. In addition, the urine may lack substances that normally help to prevent crystals from sticking together.
Therefore, not drinking enough water and dehydration from diarrhea, vomiting, or malabsorption increase the risk of stone formation. Similarly, eating a diet rich in substances that form the stones, like oxalates in spinach, purines in meat and shellfish, and phosphate in meat, fish, beans, and other protein-rich foods, makes stone formation more likely. Diets high in salt/sodium and processed sugars like fructose and corn syrup also increase the risk of stone formation. On the other hand, dietary deficiencies of chelating agents like citrate, fiber, and alkaline foods that help reduce the concentration of stone-forming crystals also increase risk.
A personal or family history of kidney stones makes it more likely someone will develop kidney stones. In addition, certain medical conditions influence the levels of the substances that make up kidney stones. For example, altered calcium metabolism occurs in metabolic disorders such as hypercalciuria (high calcium) and hyperparathyroidism. Those with gout and diabetes tend to have higher uric acid levels, predisposing them to uric acid stones.
In people with inflammatory bowel disease (IBD) or chronic diarrhea from other causes, kidney stones are more common due to chronic inflammation and malabsorption. This is due to many factors, including poor absorption of citrate, magnesium, and fats that normally help to bind calcium to excrete some excess calcium oxalate in stools instead of requiring the kidneys to remove these oxalates in the urine; imbalances in the gastrointestinal microbiome with fewer oxalate-fermenting bacterium Oxalobacter fromigenes; and loss of water and salt due to chronic diarrhea that contributes to more concentrated urine.
Other imbalances in the gut microbiome, such as dysbiosis or small intestinal bacterial overgrowth (SIBO), can also contribute to elevated uric acid levels and the risk of kidney stones. Chronic stress can contribute to imbalances in gut bacteria and inflammation while increasing uric acid levels in the body and making kidney stones more likely.
Being overweight and gaining weight also increases the risk of kidney stones, especially in women. Obesity, high blood pressure, and hypothyroidism put additional stress on the kidneys, making it more challenging to eliminate uric acid, calcium, and other waste products from the body.
Some medications can increase the risk of developing kidney stones, including diuretics (water pills), excessive use of laxatives, large doses of citric acid/vitamin C supplements, calcium-based antacids, and antibiotics like ciprofloxacin and ceftriaxone.
Functional Medicine Labs to Test for Root Cause of Kidney Stones
Functional medicine labs can help get to the root cause of kidney stones. Practitioners can use the results from these labs to create treatment and preventative protocols.
Blood Testing for Calcium, Phosphorus, and Uric Acid
Blood testing can be used to assess various biochemical issues and levels of different vitamins, minerals, and electrolytes in the blood. Elevated uric acid and calcium in the blood increase the risk of kidney stones, while alterations in phosphorus balance also may contribute to calcium kidney stones. Vitamin A deficiency, vitamin K2 deficiency, and vitamin D excess all influence calcium metabolism in ways that can increase the risk of kidney stones.
Uric acid, phosphorus, and calcium can be measured in the blood to assess their balance in the body. These levels can be assessed along with parathyroid hormone, which increases the reabsorption of calcium while increasing the excretion of phosphorus, and vitamin D levels to assess biochemical imbalances involving calcium and phosphorus metabolism.
Levels of vitamin A and K2 can also be assessed via the blood.
Kidney Function Testing
Blood testing can evaluate how well the kidneys are functioning. Blood urea nitrogen (BUN) measures the amount of urea nitrogen in the blood, reflecting how well the kidneys are functioning to remove wastes. Similarly, creatinine and glomerular filtration rate can also be measured via the blood to assess kidney functioning.
Urinalysis
Testing of the urine can look for crystals, bacteria, blood, and white cells to evaluate levels of wastes and minerals and signs of infection. A 24-hour urine collection test, including measuring calcium and uric acid, may be used to assess if too many stone-forming minerals or too few stone-preventing substances are being excreted in the urine.
Comprehensive Stool Test
Imbalanced gut bacteria can decrease the breakdown and clearance of uric acid and oxalates from the body and lead to an increased risk of stones.
Measure Hydration Status and Metabolic Balance
A comprehensive metabolic panel (CMP) provides a look at hydration status, blood sugar balance, and kidney function to assess these factors that can contribute to the risk of kidney stones.
Small Intestinal Bacterial Overgrowth (SIBO)
Since SIBO can contribute to problems breaking down uric acid, a breath test can evaluate the overgrowth of bacteria that do not normally belong in the small intestine. The 3-hour SIBO assessment is a non-invasive breath test that measures hydrogen and methane to evaluate bacterial overgrowth in the small intestine.
Thyroid Function
A Complete Thyroid Panel, including thyroid-stimulating hormone (TSH), T3 (free and total), T4 (free and total), and reverse T3, should be assessed using functional medicine ranges since thyroid hormone imbalances contribute to the build-up of uric acid in the blood.
Additional Lab Tests to Check
An ultrasound of the kidney can be used to assess the size and location as well as possible obstruction of the urinary tract by a kidney stone. Alternatively, abdominal X-rays, intravenous pyelogram (IVP), retrograde pyelogram, MRI scan of the abdomen and kidneys, or an abdominal CT scan may be used.
Laboratory analysis of passed stones can be helpful in assessing the specific type and makeup of kidney stones and guide treatment to prevent future stones.
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Conventional Treatment for Kidney Stones
Treatment of kidney stones is tailored to their size, type, and location, as well as addressing any complications that develop. Often, uncomplicated kidney stones can pass on their own and only require conservative treatment with adequate hydration and pain control.
If stones are large or not moving through the urinary tract on their own, they can be targeted with shockwave lithotripsy to break up the stones with high-energy sound waves so the smaller pieces can pass through the urinary system and out of the body.
Alternatively, a physician may use a cystoscope to look inside the urethra and bladder to find a stone in your urethra or bladder or a longer ureteroscope to visualize the lining of the ureters and kidneys. Once a stone is found, the scope can allow for its removal or break it up into smaller pieces to remove or pass. Similarly, when large stones lodge in the kidneys, doctors can use a nephroscope inserted directly into the kidney through a small cut made in the back to locate and remove a kidney stone (percutaneous nephrolithotomy).
Conventional treatment to address recurrent kidney stones and prevent the future development of stones is tailored to the type of stone. Passed stones can be collected by straining the urine and evaluated for composition.
Integrative Nutrition Treatment for Kidney Stones
An integrative nutrition approach can help treat and prevent the formation of kidney stones. Here are the top recommendations:
Eat Fewer Oxalates
In people prone to forming calcium oxalate stones, it can be helpful to reduce foods that are rich in oxalates, such as rhubarb, beets, okra, spinach, Swiss chard, sweet potatoes, nuts, tea, chocolate, black pepper, and soy products.
When oxalate-rich foods are consumed in a meal together with foods that are rich in calcium, the oxalate and calcium from the foods are more likely to bind to one another in the digestive tract before entering the kidneys. This makes it less likely that kidney stones will form. Cooking these foods can also help to reduce the oxalate content.
Moderate Animal Protein
Eating animal proteins raises the amount of acids that the kidneys have to process, resulting in reduced excretion of substances that help to reduce the formation of kidney stones like citrate. Therefore, limiting animal protein intake can help prevent recurring calcium stones.
Since foods like shellfish, organ meats, commercially produced red meat and poultry, beer, and yeast are high in purines which are metabolized to produce uric acid, reducing the intake of these foods can help to decrease the risk of uric acid stones.
Stay Hydrated
Adequate and consistent hydration is important for keeping the urine dilute of waste and passing regularly through the system. Hydration needs vary based on many individual factors, but it is generally recommended that people with a history of kidney stones drink enough water to pass about 2.1 quarts (2 liters) of light and clear urine a day.
Adding lemon to your water can have additional benefits. The citric acid found in lemons, limes, and other citrus fruits (not to be confused with ascorbic acid or vitamin C) inhibits stone formation.
Be Careful with Salt Intake
Sodium and calcium share the same transport in the kidney, so consuming foods that are high in sodium, like processed foods, will increase the amount of calcium excreted in the urine. Therefore, a high-sodium diet can increase your chances of developing another stone. Restricting dietary salt intake reduces calcium excretion in the urine and helps to prevent recurrences of idiopathic calcium stones.
Supplements & Herbs for Kidney Stones
Along with diet, supplements can be helpful for treating and preventing kidney stones. Below are some evidence-based recommendations:
Get Enough Magnesium
Magnesium helps to reduce the formation of kidney stones. Ensuring adequate magnesium intake via supplementation or Epsom salts (magnesium sulfate) baths may help prevent stones.
Avoid High Doses of Vitamin C Supplements
High-dose vitamin C supplements can increase the number of oxalates produced in the body, increasing the risk for kidney stones. It is generally recommended to avoid excess amounts over 1000 mg/day.
Address Gut Health
Optimizing digestive health and gut function and addressing any bacterial overgrowth or SIBO can help prevent kidney stones. Emerging research suggests that the intestinal microbiome plays a key role in the pathogenesis of kidney stone formation. Keeping the microbiome balanced with an anti-inflammatory diet of diverse plant foods, naturally probiotic-rich fermented foods like sauerkraut and kimchi, and potential supplementation with probiotic bacteria, especially O. formigenes, Lactobacillus spp., and Bifidobacterium spp., which can degrade dietary oxalates in the gastrointestinal tract may help reduce urinary oxalate levels and stone formation.
Herbal Approaches
While many phytotherapies have been used traditionally and studied for the prevention of kidney stones, additional conclusive studies are needed in humans. One plant that shows promise is Phyllanthus niruri, a plant traditionally known as the gale of the wind or stonebreaker, which has been studied for stone prevention due to its ability to block calcium oxalate crystallization and reduce oxalates and uric acid in the urine.
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Summary
Urolithiasis is the condition where stones are formed anywhere along the urinary tract. These stones are composed of accumulated mineral salts that form crystal clumps. The most common type of kidney stone is composed of calcium oxalate or phosphate. Other stones may be formed from uric acid, struvite, and cystine.
Kidney stones can cause significant pain when they grow large enough and/or move through the urinary tract. In addition, they may cause blood in the urine, increased urinary frequency, and nausea/vomiting.
Common risk factors for developing kidney stones include dehydration, high intake of animal-derived protein, high oxalate intake from foods such as beans, beer, berries, coffee, chocolate, some nuts, some teas, spinach, beets, and potatoes, and high salt intake. A family history of kidney stones and various medical conditions such as inflammatory bowel disease, obesity, and hypertension also increases the risk that stones may develop.
While symptomatic kidney stones generally require acute medical attention, functional medicine can utilize testing and treatment approaches to address underlying contributors and prevent a recurrence. Blood testing can measure levels of various substances that make up kidney stones as well as assess kidney function. Testing of the urine can look for crystals, bacteria, blood, and white cells to evaluate levels of wastes and minerals and signs of infection.
An anti-inflammatory diet that incorporates calcium-rich foods and lemon water for adequate hydration while avoiding excessive animal protein, sodium, and high-oxalate foods like spinach, rhubarb, chocolate, black tea, and wheat bran can help prevent kidney stones from forming. In addition, maintaining a healthy gut microbiome and getting enough magnesium may reduce the risk of stones.
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