Kidney stones and Diet
Kidney stones also referred to as renal calculi, are very hard pebble-like deposits that form inside the kidneys. They are excruciatingly painful and most individuals seek immediate medical assistance. Besides the pain, if kidney stones are left untreated they can cause damage to the kidney. There are many causes of kidney stones including excess body weight, diet, and the use of certain medications and supplements. Kidney stones can affect any segment of the urinary tract including the ureters and bladder.
What size are kidney stones?
The size and shape of kidney stones is variable. The majority are small like a grain of salt, but they can be as large as a peanut. In rare cases, some stones may be as large as a golf ball. Kidney stones also vary in texture and can be smooth, rough, or jagged. The color of kidney stones can vary from black, brown to yellow.
How common are kidney stones?
Kidney stones are very common and the incidence has been increasing over the past few decades. It is estimated that nearly 6% of women and 11% of men in the US will develop a kidney stone at some point in their lifetime.
What are the symptoms of kidney stones?
When kidney stones develop they may move within the kidney or pass into the ureter. When the stone becomes lodged into the ureter, the majority of individuals will develop symptoms which include the following:
- Severe pain that starts below the rib cage on the side and back
- The pain often comes in waves and will radiate to the lower abdomen and groin area
- The intensity of pain is usually severe
- The pain is burning in nature
- The pain is worse when urinating
- The individual will generally not be able to lie still even for a few seconds
- Urine may appear pink due to blood
- The urine may smell if there is an associated infection
- Nausea and vomiting
- Urge to urinate frequently
- Fever and chills if there is an infection
What are the complications of kidney stones?
Kidney stones can be associated with several complications and they include:
- Blood in the urine which can be microscopic or a large amount
- Severe pain that often requires prescription-strength pain medications
- Urinary and kidney infections
- Damage to the kidney leading to loss of function
Which population is likely to develop kidney stones?
While anyone can develop kidney stones, some populations are at a higher risk and they include the following:
- Non-Hispanic whites
- Men are more likely than women
What Causes Kidney stones?
There is no single cause for kidney stones but the presence of certain factors may increase the risk of developing a stone. Kidney stones are formed when minerals-like calcium, uric acid, or oxalate crystallizes in the kidney. The crystallization may occur because the urine environment may have changed (e.g. dehydration or a change in pH).
Types of Kidney stones
There are several types of kidney stones and knowing the type helps the healthcare provider recommend strategies for prevention. Therefore, all individuals are asked to save the kidney stone when it is passed in the urine and give it to the doctor.
Types of kidney stones include:
- Calcium stones make up the majority of kidney stones. They are usually in the form of calcium oxalate. Oxalate is produced daily by the liver and is also found in many foods and absorbed in the intestine. Foods high in oxalate include nuts, chocolate, and certain fruits and vegetables. Besides diet, intestinal bypass surgery, high doses of vitamin D, and several electrolyte and metabolic conditions can elevate the level of calcium and/or oxalate in urine.
- Calcium stones made of calcium phosphate can also occur and are most common in individuals with renal tubular acidosis and those who use medications to treat seizures and migraines (eg topiramate).
- Struvite stones usually occur in the presence of a urinary tract infection and consist chiefly of magnesium and phosphate. These stones tend to be large and often occur in the bladder
- Uric acid stones tend to form in individuals with the following conditions
- Chronic diarrhea
- Eating a high protein diet
- Metabolic syndrome
- Certain genetic disorders
- Cystine stones tend to occur in individuals with a genetic disorder called cystinuria, where the kidneys excrete excess a specific amino acid
What are risk factors?
Certain risk factors increase the risk of kidney stones and they include:
- Family history: if someone in your family has had a diagnosis of kidney stones, then you are also more likely to develop stones.
- Personal history: If you have developed kidney stones once, then you may be at a higher risk for recurrent stones
- Dehydration is a universal risk factor for most kidney stones. Individuals who reside in warm and dry climates, those who sweat excessively or do not drink enough fluids are at high risk for kidney stones
- Diet is a known risk factor for kidney stones. Individuals who consume a high protein, high sugar, and salt diet are predisposed to forming kidney stones. A high protein diet is a risk factor for uric acid stones
- Being overweight or obese is known to be associated with kidney stones
- Individuals with intestinal disorders like inflammatory bowel disease or those who have undergone gastric bypass surgery are also at risk for kidney stones. The reason is that these disorders cause alterations in the digestive processes that affect the absorption of calcium and water, which lead to stone formation
- Medical disorders that increase the risk of kidney stones include hyperparathyroidism, recurrent urinary tract infections, and renal tubular acidosis
- Studies show that individuals who consume high doses of vitamin C are also at risk for developing kidney stones- the reason is because vitamin C is coveted to oxalate in the liver.
Medications That can cause Kidney stones
- Water pills or diuretics cause dehydration and increase the risk of stones
- Calcium-based antacids to treat ulcer disease
- Drugs to treat HIV like indinavir can cause kidney stones
- The drug topiramate to treat migraines and seizures has also been linked to kidney stones
- Kidney stones may also occur in individuals who use milk of magnesia
How is the diagnosis of kidney stones made?
- Today when a person presents with pain suggestive of kidney stones, the first test of choice is the CT scan- which can identify very small stones anywhere in the urinary tract.
- At the same time, blood and urine work is done.
Once the diagnosis of kidney stone is made, the management depends on the cause and type of stone.
- The majority of small kidney stones do not require any invasive therapy. These stones usually pass into the urine on their own. However, to facilitate removal by the kidney, one should drink as much as 2-3 liters of fluid every day. The fluid also prevents other stones from forming. The fluid of choice is plain water
- Most individuals will require a strong pain pill for relief.
- In some cases, the healthcare provider will prescribe a medication to relax the muscles in the ureter, which also helps pass the stone down the ureter without much pain.
- Large stones often cannot pass on their own and may cause significant pain, bleeding, or even kidney damage. Thus some types of procedure may be required to remove the stones.
To prevent and reduce the risk of stones and damage to the kidney, it is important to make the following lifestyle changes:
- Drink ample water every day. Healthcare workers recommend drinking 2-3 liters of water every day. This will help flush out the small stones in the urine
- If you reside in an environment that is hot and dry or if you perform intense exercise, you may need to drink lots of water to produce urine that is clear and light-colored
- Omit oxalate-rich foods if you were diagnosed with calcium oxalate stones. The oxalate-rich foods include:
- Swiss chard
- Sweet potatoes.
- Soy products
- Black pepper
- If you are diagnosed with urate stones, you need to decrease the intake of red meat and salt. Instead, consider a low salt, plant-based diet
- While you can continue to eat calcium-containing foods, you should avoid the use of calcium supplements
- Consult with a dietitian who can help you with a diet plan to lower the risk of kidney stones
Several medications can be prescribed to prevent certain types of kidney stones.
If you have been diagnosed with kidney stones, it is important to see a healthcare worker to ensure that your kidneys have not been damaged. The key is to prevent stones from recurring again and this can be done by making lifestyle changes. For more tips on anything and everything kidney related, be sure to check out the Healthy Kidney Inc. YouTube.