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  • Dr. Mercola

Kidney Stones: Prevention Is Easy

Roughly 1 million Americans develop kidney stones each year. Once you have had one kidney stone attack, your chance of recurrence is about 70 to 80 percent. Family genetics can increase your risk. And the younger you are when you have your first attack, the greater your risk of recurrence.

Records of kidney stones can be found since the beginning of civilization. Lithotomy, a surgical procedure for removing stones, is one of the earliest known surgical procedures. In fact, a caution about the dangers of surgically removing stones is even found in the text of the Hippocratic Oath.

If you are a man, your risk for kidney stones is four times greater than if you are a woman. And if you live in the southeastern part of the U.S., also referred to as the "Kidney Stone Belt," your risk is even greater due to higher rates of dehydration.

In the Middle East, kidney stone rates are nearly double what they are in the U.S., due to the warmer climate.

Kidney stones can range in size from a grain of sand to larger than a golf ball. If a stone fails to pass, permanent damage to your urinary tract can result.

This is not something to ignore -- not that you could easily ignore such a painful episode.

The number of cases of adult kidney stones appears to be on the rise, most likely as a result of modern diets. And now, kidney stones are being seen in children in unprecedented numbers[1] ... just one more sad result of our modern dietary habits.

Fortunately, 90 to 95 percent of kidney stones pass within a number of days or weeks, without any intervention at all. And, even better news -- the best remedy is also the best prevention, and also happens to be the least expensive: simply drink more water.

Recognizing a Kidney Stone Attack

Your kidneys are responsible for removing excess fluid from your body and filtering out unneeded electrolytes and wastes from your blood, resulting in the production of urine.

Kidney stones form when the minerals and acid salts in your urine crystallize, stick together, and solidify into a mass. This happens when your urine contains more crystal-forming substances, such as calcium and uric acid, than the available fluid can dilute. This can happen when urine is highly acid or highly alkaline.

The conditions allowing kidney stones to form are created by problems in the way your body absorbs and eliminates calcium and other substances. Sometimes the underlying cause is a metabolic disorder or kidney disease.

Certain drugs can also promote kidney stones, such as Lasix (furosemide), Topomax (topiramate), and Xenical, among others. Many times, it is a combination of factors that create an environment favorable to stone formation.

You won't know you have a stone until it moves into the ureter-the tube connecting your kidney and your bladder. Common symptoms include[2]:

  1. Pain in your side and back, below your ribs

  2. Episodes of pain lasting 20 to 60 minutes, of varying intensity

  3. Pain "waves" radiating from your side and back, to your lower abdomen and groin

  4. Bloody, cloudy or foul-smelling urine

  5. Pain with urination

  6. Nausea and vomiting

  7. "Urgency" (persistent urge to urinate)

  8. Fever and chills (indicates an infection is also present)

The pain is a result of distention of the tissues above the stone, since it is blocking the passage of urine, rather than from the pressure of the stone itself.

Four Types of Kidney Stones

Most kidney stones contain crystals of multiple types. However, usually one type predominates, and determining the type helps you identify the underlying cause3:

1. Calcium stones. The most common type (four out of five cases)is usually in the form of calcium oxalate. Oxalate is found in some fruits and vegetables, but your liver produces most of your oxalate. If you are found to have oxalate stones, your doctor may recommend avoiding foods rich in oxalates, such as dark green vegetables, nuts and chocolate.

2. Struvite stones: Found more often in women, these are almost always the result of urinary tract infections.

3. Uric acid stones. These are a byproduct of protein metabolism.They're commonly seen with gout,and may result from certain genetic factors and disorders of your blood-producing tissues.

4. Cystine stones. Represent a very small percentage of kidney stones.These are the result of a hereditary disorder that causes your kidneys to excrete massive amounts of certain amino acids (cystinuria).

Many Risk Factors are Under YOUR Control

The number one risk factor for kidney stones is not drinking enough water. If you aren't drinking enough, your urine will simply have higher concentrations of substances that can form stones.

How do you know if you are drinking enough water?

You want your urine to be a light yellow. Every person's water requirement is different, depending on your particular system and activity level, but simply keeping your urine light yellow will go a long way toward preventing kidney stones. Remember to increase your water intake whenever you increase your activity, and when you're in a warmer climate.

If you happen to be taking any multivitamins or B supplements that contain vitamin B2 (riboflavin), the color of your urine will be a very bright nearly fluorescent yellow and this will not allow you to use the color of your urine as a guide to how well you are hydrated. Waiting until you feel thirsty is often too late. Thirst usually signifies dehydration.

Healthy Lifestyle is KEY to Avoiding Kidney Stones

Another risk factor is being sedentary. You're more prone to kidney stones if you're bedridden or very sedentary for a long period of time, partly because limited activity can cause your bones to release more calcium. High blood pressure doubles your risk for kidney stones. Digestive problems also increase your risk, since changes in the digestive process affect your absorption of calcium and other minerals.

A diet high in sugar can set you up for stones, since sugar upsets the mineral relationships in your body by interfering with calcium and magnesium absorption. Not only does sugar and high fructose corn syrup lead to obesity and diabetes, but also the current over-the-top consumption of these unhealthy sugars by children is a large factor in why children as young as age 5 or 6 are now turning up with kidney stones.

A 1999 South African study[3] found that drinking soda exacerbates conditions in the urine that lead to formation of calcium oxalate kidney stone problems.

Diets high in processed salt are also bad news. Salt increases the amount of calcium and oxalate in your urine. And processed foods are extremely high in salt.

Dr. Bruce L. Slaughenhoupt, co-director of pediatric urology at the University of Wisconsin, reports a huge increase in the salt load of children's diets -- from salty chips, French fries, sandwich meats, canned soups, and sports drinks like Gatorade, which are now sold in child-friendly juice boxes. He believes the overconsumption of processed foods by children today is the cause of increased kidney stones in children.

Not surprisingly, there also appears to be a connection between childhood obesity and kidney stones.[4]. Children are notorious for not drinking enough water, adding to the problem.

Consumption of soy can predispose you to developing kidney stones due to high levels of oxalate present in many varieties of soybeans. One more nail in the coffin for non-fermented soy! And finally, caffeine has been linked to kidney stones. In one study, caffeine was given to people with a history of kidney stones, after which their urine was examined. The subjects showed elevated urine calcium, putting them at higher risk for kidney stones.

What About Your Calcium Intake?

In the past, kidney stone sufferers have been warned to avoid foods rich in calcium. However, there is now evidence that avoiding calcium may do more harm than good. The Harvard School of Public Health conducted a study of more than 45,000 men. The men who had diets rich in calcium had a one-third lower risk of kidney stones than those with lower calcium diets[5].

Why would this be? It seems counterintuitive. After all, calcium is the largest component in the stones.

The answer is that high dietary calcium actually blocks a chemical action that causes the formation of the stones. It binds with oxalates (from foods) in your intestine, which then prevents both from being absorbed into your blood and later transferred to your kidneys.

So, urinary oxalates may be more important to formation of calcium-oxalate kidney stone crystals than is urinary calcium.

It is important to note that it is the calcium from foods that is beneficial -- not calcium supplements, which have actually been found to increase your risk of kidney stones by 20 percent[6].

Busting the Myth That High Protein Diets Lead to Kidney Stones

In the 1990s when the Atkins diet reached huge popularity, critics claimed that high protein intake leads to kidney stones. This turned out to be a complete myth, but the misinformation is still being circulated.

Although protein restricted diets are helpful for people who already have kidney disease, eating meat does not cause kidney problems[7]. Furthermore, the fat-soluble vitamins and saturated fat found in animal foods are pivotal for the proper functioning of your kidneys.

"Don't Do Something -- Just Sit There!"

As with most things, the best approach is the safest and simplest--letting the stone pass on its own. This might take days, or weeks in some cases, but the key is to drink enough water -- NOT soda -- to decrease the concentration of solids in your urine to the point that the stone will be dissolved.

Avoid drinking tea since it is high in oxalates.

There are several medical procedures and surgical techniques that can be used to treat kidney stones, but the risks are high enough that physicians typically shy away from them, unless there's no other choice. This is actually a good thing, considering the multitude of problems American patients face due to medical errors. Pain medications will usually be offered, if your pain level is intolerable. Some medicinal herbs have been identified to be helpful for acute episodes, including:

  1. nettle leaf[8]

  2. bearberry

  3. cleavers

  4. corn silk

  5. crampbark

  6. gravel root

  7. kava kava

  8. khella

  9. hydrangea

  10. stone root[9]

You should always consult the advice of an expert herbalist, since herbs can be every bit as potent as pharmaceuticals and may cause harm if used improperly.

Of course, even better than letting a kidney stone pass naturally would be if you never had to deal with this very painful problem in the first place.

Lifestyle Modifications for Healthy Kidneys

In summary, a few lifestyle modifications will go a long way toward preventing a painful kidney stone attack:

  1. As discussed previously, stay well hydrated

  2. Eat a diet based on your body's unique nutritional type

  3. Avoid taking prescription drugs that harm more than they heal

  4. Avoid sugar, soy, caffeine, excess salt, and processed foods

  5. Get plenty of exercise to keep your body's fluids moving

  6. Make sure you're getting adequate magnesium and vitamin B6 in your diet, which have both been suggested to help prevent kidney stone formation

Lifestyle changes always take some effort and might seem inconvenient at first. But compared to the painful process of passing a kidney stone, a few lifestyle changes are a cinch!


[1] Tarkan L. A rise in kidney stones is seen in U.S. children. The New York Times (online), October 27, 2008

[2] Kidney Stones,

[3] Rodgers A. Effect of cola consumption on urinary biochemical and physicochemical risk factors associated with calcium oxalate urolithiasis. Urol Res. 1999;27(1):77-81

[4] "Kidney stones in children on the rise, expert says," ScienceDaily (May 5, 2009)

[5] Curhan GC, Willett WC, Rimm EB, Stampfer MJ. A prospective study of dietary calcium and other nutrients and the risk of symptomatic kidney stones. N Engl J Med. 1993 Mar 25;328(12):833-8

[6] Baxter R. The Kidney Stone Web Site.

[7] Dwyer JT, et al. Diet, indicators of kidney disease, and later mortality among older persons in the NHANES I Epidemiologic Follow-Up Study. Am J Public Health. 1994 Aug;84(8):1299-303

[8] "18 home remedies for kidney stones,"

[9] "Kidney Stones: Alternative Treatment," Urologychannel

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