kidneys kidneys

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Two organs shaped like giant chili beans lying within your lower back. They remove excess water, salts, and other substances from the blood and send it out as urine. This keeps the blood's pH, water and chemical composition in balance. This removed waste travels through the ureters and empties into the bladder, where it is stored until urination occurs.

User's Manual

If you've gotta go... Go! Do not make a habit of holding your urine for long periods of time. Your body is telling you that pressure is building up inside your bladder and it needs a release.

Kidney stones

Kidney stones are formed when tiny crystals separate from the urine and collect inside the kidney forming a small stone. Stones can develop over a period of months or even years. The size of a kidney stone can range from a small speck to the size of a golf ball! luckily most people's urine contains chemicals that prevent the formation of these crystals. However, every year up to a million people are diagnosed with kidney stones. An estimated 10% of the people living in the U.S. will develop kidney stones at some point in their lives. If you're prone to kidney stones you could have them as early as your twenties. Although they usually don't occur until after you turn 30, it might help to develop habits that will avoid these painful little guys in the future.

Who's at risk:

Anyone can get a kidney stone. However some are at more risk than others.

White Americans are more likely to develop a stone than Black Americans.

Men are 4 times as likely to develop kidney stones than are women. Stones occur most typically in men ages 20 to 40.

If you live in the southeastern U.S. you're more likely to get kidney stoned.

If you commonly have urinary tract infections you are at a higher risk for "struvite kidney stones."

You are at an exceptionally high risk for oxalate kidney stones if...

  • You have a family history of oxalate kidney stones
  • You have already had an oxalate kidney stone
  • You have a disorder such as Hypercalciuria, hyperoxaluria, hyperuricosuria, cystinuria, cystic kidney disease, renal tubular acidosis, hyperparathyroidism, or gout.

Kidney Stone Types, Causes and Prevention

Oxalate Kidney Stones
The most common kidney stone is composed of calcium oxalate and calcium phosphate. These make up 70% to 80% of all kidney stones reported in the US. Because of this, people used to avoid dairy products high in calcium to prevent kidney stones. This is wrong! Today, we know that foods high in calcium, including milk and most other dairy products, actually help prevent oxalate kidney stones from forming. This is because the calcium in the food absorbs the oxalate and phosphate in the digestive tract before it enters the blood so these crystals never make it to the kidneys. Instead the oxalate and phosphate is flushed out of the body through the digestive tract. A diet high in calcium is good for you. It's good for your muscles, your bones and your kidneys. Calcium only becomes a problem when it is abnormally excreted into the kidneys. This can be caused by a disorder or by eating too much sugar. Too much sugar causes your pancreas to release insulin, which causes extra calcium excretion in your urine. So keep your sweets in moderation. Dehydration can also lead to a high concentration of calcium oxalate in the urine. When you exercise especially in a hot climate make sure you are guzzling water. The rest of the time, you should still make sure to drink lots of water. Water is the number one most important nutrient in your diet. Large doses of vitamin C and a lack of vitamin B can cause excess oxalate in the urine, leading to this type of kidney stone. Although vitamin C is good for you in many ways, those of you who are at an exceptionally high risk for oxalate kidney stones due to your family history, having suffered from one already, or having a disorder, should limit your daily vitamin C intake to 100 to 200 mg per day.

The second most common kidney stones are Struvite stones. This type of kidney stone is caused by recurrent urinary tract infections in women. So try to keep the opening to your urinary tract (near the vagina) clean, as well as anything that might come into contact with it clean. If you find you are having many urinary tract infections, ask your doctor for advice. Vitamin C and cranberry juice can work wonders. For this particular type of stone, Vitamin C is a good thing. So as you can see, different kidney stones require different ways of prevention. The trick is to find out whether you are at risk for one or the other and then plan your diet, including your vitamin C intake, accordingly.

Kidney Stone Prevention

Those of you who are at an exceptionally high risk for oxalate kidney stones: meaning you have a family history of oxalate stones, you've had one already, or you have a disorder that makes you prone to oxalate stones...

  • Drink plenty of water.
  • Drink and eat plenty of dairy products - Milk does a body good!
  • Avoid foods that cause a significant increase in oxalate excretion into the urine: spinach, rhubarb, beets, nuts, chocolate, tea, wheat bran and strawberries
  • You may also consider limiting eggs, fish, animal fat and protein, which also increase oxalate content in the urine.
  • Supply your body with Vitamin B's which prevent oxalate excretion, by eating carrots, peas, raisins, broccoli, milk, or potatoes (37mg 3 times a day for teens, 50mg 3 times a day for adults).
  • Supply your body with Vitamin B6 by eating carrots (a Vitamin B6 powerhouse), and don't forget potatoes, corn, cantaloupe broccoli, beans and bananas.

Women, to prevent Struvite Stones...

  • Keep your urinary tract free of infection.
  • Take showers regularly with soap and water to keep yourself nice and clean.

If you are not at high risk for oxalate stones...

  • Maintain the urine's pH with vitamin C from oranges or orange juice to prevent urinary infection and struvite kidney stones.
  • Zinc also promotes healing and prevents struvite crystals. Get your zinc by eating mushrooms, sunflower seeds, lima beans, pecans, and as long as you don't overdo it - egg yolks and poultry. (40 to 60mg of zinc daily for teens and 50 to 80mg daily for adults)


  • Drink lots of water to dilute the toxins in the kidneys and to flush crystals out of the body. Most of us are dehydrated. If you are thirsty you are already dehydrated. If your urine is deep orange-yellow you are dehydrated. Drink up. There's plenty for everyone.
  • Avoid always sleeping on the same side. A study found that 93 out of 110 patients with kidney stones preferred sleeping on one side and spent large amounts of time sleeping on that particular side.

What if you get a kidney stone?
Most kidney stones pass out of the body through the urine without help from a doctor. Stones that remain in the kidney causing lasting symptoms or complications can be treated using various non-surgical techniques. Most often surgery is unnecessary. If you notice blood in your urine or feel a sharp pain in your back or side, see your physician.

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Amazing Facts

Your kidneys work their cortexes off!

  • Every minute your kidneys process 2.75 pints or 1.3 liters of blood.
  • Every hour your kidneys process every drop of your blood 20 times.
  • Every day your kidneys purify the body's entire volume of fluid 15 times.
  • Daily urine composes 1/1000 of your body's fluid content.
  • Daily urine output can range from a single cup if you're dehydrated to more than 5.5 gallons or 20 liters if you are well hydrated.
  • Urine normally leaves the kidney at 1 drop/minute.

Evidence of kidney stones have been found in a 7000 year old Egyptian mummy.

Related Links

Urogenital System
Nutrition - Water