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Benefits of Drinking Water

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  • The number one risk factor for kidney stones is not drinking enough water
  • People who produced 2 to 2.5 liters of urine daily were 50 percent less likely to develop kidneys stones than those who produced less
  • It generally took drinking eight to 10 eight-ounce glasses of water daily to produce that amount of urine, but a simpler option is to use the color of your urine as a guide (it should be pale yellow)

Drinking Water Helps Prevent Kidney Stones

November 16, 2015 | 66,000 views
| Available in EspañolDisponible en Español

By Dr. Mercola

If you've ever suffered with a kidney stone, the pain is something you will likely not forget… and certainly want to avoid in the future. Kidney stones can cause excruciating pain in your sides and back that may spread through your lower abdomen and groin.

The pain sometimes comes in waves and, generally, the larger the stone, the more pain and symptoms it will cause. While most kidney stones pass on their own without causing damage, more than half a million people go to US emergency rooms each year due to kidney stones.1

Today, with rates continuing to rise, kidney stones will impact one in 10 US adults at some point during their lives2 -- usually between the ages of 20 and 50.

Want to Prevent Kidney Stones? Drink More Water

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

Specifically, stone-forming chemicals including calcium, oxalate, urate, cysteine, xanthine, and phosphate will have less chance to settle and bond in your kidneys and urinary tract if you're urinating frequently.3

According to the results of a large meta-analysis, presented at a March 2015 National Kidney Foundation meeting in Dallas, Texas, people who produced 2 to 2.5 liters of urine daily were 50 percent less likely to develop kidneys stones than those who produced less.

It generally took drinking about eight to 10 eight-ounce glasses of water daily to produce that amount of urine. According to Kerry Willis, chief scientific officer at the National Kidney Foundation:4

"Kidney stones cause significant discomfort and cost, along with a potential to contribute to the development of kidney disease, so confirmation of reducing risk through improved hydration is an important finding."

Last year, new guidelines issued by the American College of Physicians (ACP) also called for people who have had a kidney stone in the past to increase their fluid intake so they have at least two liters of urine per day, which they say could decrease stone recurrence by at least half.5

To achieve this, they recommend increased fluid intake spread throughout the day, pointing out that both water and mineral water are beneficial.

Research shows, for instance, among patients with kidney stones that those who increase hydration to reach two liters of urine a day had a 12 percent recurrence rate compared to 27 percent among those who didn't increase their fluid intake.

The National Kidney Foundation recommends drinking more than 12 glasses of water a day, but a simpler way to know if you are drinking enough water is to check the color of your urine; you want your urine to be a very light, pale yellow (darker urine is more concentrated).

What Are the Different Types of Kidney Stones?

When your urine contains more crystal-forming substances than the fluid can dilute, kidney stones may form. In some people, urine may also lack substances that help keep crystals from sticking together, which encourages kidney stone formation.

There are varying types of kidney stones, however, and knowing which type you have can help you get to the bottom of the underlying causes:6

  1. Calcium Stones. The most common variety, most kidney stones are made of calcium oxalate. Oxalate is found in some fruits and vegetables, but your liver produces most of your oxalate.
  2. 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, but drinking more water can also be effective.

  3. Struvite stones. Found more often in women, these are almost always the result of urinary tract infections.
  4. 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.
  5. Cystine stones. They 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).

You won't know you have a stone until it moves into the ureter—the tube connecting your kidney and your bladder. 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. Common symptoms include:7

Pain in your side and back, below your ribs Episodes of pain lasting 20 to 60 minutes, of varying intensity
Pain "waves" radiating from your side and back to your lower abdomen and groinBloody, cloudy, or foul-smelling urine
Pain with urinationNausea and vomiting
"Urgency" (persistent urge to urinate)Fever and chills (indicates an infection is also present)

9 Additional Factors That Make Kidney Stones More Likely

Once you've had kidney stones, your risk of recurrence increases. About 35 percent to 50 percent of people will have another bout with kidney stones within five years unless changes are made.8

However, many factors may increase your risk of a first kidney stone episode, even aside from not drinking enough water. Top risk factors include:

1. A Diet High in Sugar

A diet high in sugar can set you up for kidney stones, since sugar upsets the mineral relationships in your body by interfering with calcium and magnesium absorption. The consumption of unhealthy sugars and soda by children is a large factor in why children as young as age 5 are now developing kidney stones.

Sugar can also increase kidney size and produce pathological changes in your kidney, such as the formation of kidney stones. According to The National Kidney Foundation, you should pay particular attention to keeping your fructose levels under control:9

"Eating too much fructose correlates with increasing risk of developing a kidney stone. Fructose can be found in table sugar and high fructose corn syrup. In some individuals, fructose can be metabolized into oxalate."

2. Drinking Too Much Soda

Soda is high in sugar, so it makes sense that drinking too much might increase your risk of kidney stones. But aside from its sugar content, drinking soda may be associated with kidney stones because the phosphorus acid it contains acidifies your urine, which promotes stone formation.

One South African study, for instance, found that drinking soda exacerbates conditions in your urine that lead to the formation of calcium oxalate kidney stone problems.10 So if you're a soda drinker, cutting back is an important tool to remember. In one study, those with kidney stones who eliminated soda from their diet lowered their risk of recurrence by about 15 percent.11

3. Not Exercising

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. Exercise will also help you to resolve high blood pressure, a condition that doubles your risk for kidney stones.

Even low amounts of exercise may be beneficial to reducing your risk. In a study involving more than 84,000 postmenopausal women, it was found that those who exercised had up to a 31 percent lower risk of kidney stones.12 The link persisted even with only small amounts of physical activity.

Specifically, the research showed a lower risk from three hours a week of walking, four hours of light gardening, or just one hour of moderate jogging. You can find my comprehensive exercise recommendations, including how to perform highly recommended high-intensity interval training (HIIT), here.

4. Overeating

Women who ate more than 2,200 calories per day increased their risk of kidney stones by up to 42 percent, while obesity also raised the risk. It should be noted that even though obesity increases kidney stone risk, weight loss surgery that alters your digestive tract actually makes them more common. After weight loss surgery, levels of oxalate are typically much higher (oxalate is the most common type of kidney stone crystal).

5. Drinking Fluoridated Water

High levels of fluoride in water are associated with kidney stones.13 The condition was nearly five times more common in an area with high fluoride (3.5 to 4.9 parts per million, or ppm) than a similar area without high fluoride levels in the water.14 Overall, the prevalence of kidney stones in the high-fluoride area was nearly double in those with fluorosis than those without. A reverse osmosis water filtration system can remove fluoride from your drinking water.

6. Taking Certain Medications

Lasix (furosemide), Topomax (topiramate), and Xenical, among others, are known to increase the risk of kidney stones.

7. Eating Non-Fermented Soy

Soybeans and soy-based foods may promote kidney stones in those prone to them, as they may contain high levels of oxalates, which can bind with calcium in your kidney to form kidney stones. Non-fermented soy is the type found in soy milk, soy burgers, soy ice cream, and even tofu.

8. Not Eating Enough Calcium-Rich Foods

Ironically, since most kidney stones are made of calcium, the Harvard School of Public Health conducted a study of more than 45,000 men,15 and the men who had diets rich in calcium had a one-third lower risk of kidney stones than those with lower calcium diets. It turns out that a diet rich in 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.16

9. Lacking in Magnesium

Magnesium deficiency has been linked to kidney stones. An estimated 80 percent of Americans are deficient, so this could be a major factor. Magnesium plays an important role in your body's absorption and assimilation of calcium, as if you consume too much calcium without adequate magnesium, the excess calcium can actually become toxic and contribute to health conditions like kidney stones.

Magnesium helps prevent calcium from combining with oxalate, which, as mentioned, is the most common type of kidney stone. Green leafy vegetables like spinach and Swiss chard are excellent sources of magnesium, and one of the simplest ways to make sure you're consuming enough of these is by juicing your vegetables. Vegetable juice is another excellent source of magnesium, as are some beans, nuts like almonds, and seeds, pumpkin seeds, sunflower seeds, and sesame seeds. Avocados are also a good source, and it's also available in supplement form.

When Should You Seek Medical Attention for Kidney Stones?

Because kidney stones can range in size from a grain of sand to larger than a golf ball, it's important to seek medical attention, especially if you're in severe pain. In most cases, the stone will pass on its own. Though there are several medical procedures and surgical techniques that can be used to treat kidney stones, the risks are high enough that physicians typically shy away from them unless there's no other choice. Kidney stones might take days or even weeks to pass, but if a stone fails to pass, permanent damage to your urinary tract can result.

Fortunately, there are now some more advanced options other than surgery, such as extracorporeal shockwave lithotripsy. This treatment entails being submerged in a tub of water where sound waves traveling through the liquid shatter the stones. They then pass as gravel through your urine in a few days or weeks.

You should drink plenty of water during a kidney stone attack to help flush the stone out, but remember that drinking enough water regularly is one of the best ways to prevent kidney stones from forming in the first place. You certainly do not want to overdo your water intake, as this can lead to hyponatremia, in which the sodium level in your blood becomes too diluted.

However, a healthy intake of water – enough so that your urine is a very pale shade of yellow – should be your goal. Ideally, sip it throughout the day instead of trying to guzzle a few cups here and there. The latter scenario can simply cause you to urinate more without your body having a chance to absorb the extra fluid.

Finally, the tropical plant Phyllanthus niruri, which is available in supplement form, has shown promise in helping to treat and prevent kidney stones as well. Commonly known as the "stonebreaker," Phyllanthus niruri has been shown to interfere with many stages of stone formation, including reducing crystals aggregation and modifying their structure and composition.17

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