Diet to Help Prevent Kidney Stones

You can think of kidney stones as salts.  Table salt, which is sodium chloride, has a positive ion (sodium) and a negative ion (chloride).  In most people kidney stones are made up of calcium (a positive ion) and a negative ion.  This negative ion is typically oxalate or phosphate.

The first important concept is solubility, or how easily these salts dissolve.  For example, if you have table salt at the bottom of a glass and you add a little water to the glass, some of the salt will go into solution.  If you add more water, all of the salt will be dissolved into the water.

This is similar to kidney stones, but instead of water you have urine.  And instead of a glass, you have the collecting system of the kidney, and instead of table salt, you have calcium oxalate or calcium phosphate.

Preventing crystallization

An increased volume of urine can carry more calcium and oxalate in solution and prevent it from crystallizing.  It is because of solubility that increasing the amount of fluid that you drink can help guard against kidney stones.

If you become dehydrated, you run the risk of decreasing solubility and producing crystals.  Once a crystal lattice has been established in the kidney, it becomes easy for kidney stones to grow, and every time you become dehydrated, the stone will grow larger.

You may be asking, “I drink water; what else can I do to decrease risk of kidney stones?”  Calcium oxalate stones are made of calcium and oxalate.  Calcium is one of the most plentiful materials in the body.  Our bones are made of calcium so that the body contains many pounds of calcium.

For this reason, the body carefully regulates how much calcium it absorbs and excretes through three different hormonal systems.  In rare instances, these regulatory systems can malfunction, and for this reason, a urologist may perform a 24-hour urine test to determine whether these systems are malfunctioning.  It is usually nothelpful to severely restrict the amount of calcium intake.

The role of diet

However, you can do something about the amount of oxalate that you ingest. The liver makes 70 percent of the oxalate in the body, but 30 percent comes from diet.  Foods containing oxalate include coffee, tea, colas, chocolate and green leafy vegetables such as spinach.  This doesn’t mean that you can never have these foods again.  However, it would be best to consume these foods in moderation.

In addition to reducing dietary oxalate, you should stop taking vitamin C and vitamin D supplements, as well as calcium supplements and antacids containing calcium.  You should also reduce added salt in your diet, eat meat in moderation, and increase consumption of citrus.

Chance of Kidney Stone Passage

Size Upper Middle Lower
1 100 85
2 100 83 69
3 42 55 69
4 20 62 55
5 6 57 45
6 0 0 25
7-9 0 0 0
10-12 0


Contact us to learn more about how your diet can prevent or cause kidney stones.