For all types of
stones increasing water and fluid consumption is a primary component
of treatment to increase urine volume. By increasing the volume of urine, it becomes
more dilute. Salt crystals (i.e. calcium oxalate, calcium
phosphate, uric acid and cystine) are less likely to form/precipitate in a large
volume, dilute urine. It's the same concept as pooring table
salt into water. The more water, the more salt it can hold
without salt crystals forming.
interventions are directed towards the type of kidney stone that
forms and also possible underlying medical conditions. The
dietary interventions for specific types of stones or associated
diseases are discussed below.
associated with hypercalciuria: People
with hypercalciura excrete too much calcium into the urine.
It is a genetic disorder that runs in families and is very common
amongst people who form stones. After other causes of high
urinary calcium are excluded (including high salt diet,
hyperparathyroidism, certain cancers, and sarcoidosis) dietary treatment
includes increasing water/fluid intake and a low protein diet. Protein in
the diet increases calcium loss in the urine. Dietary changes
usually do not include restricting dairy or other calcium containing
products. In fact, people with this disorder lose significant amounts
of calcium from their bones. If calcium intake is limited,
in bone density can occur. In addition, calcium in the diet at
mealtimes binds to oxalates contained in the food. The
resulting calcium oxalate complexes are incapable of being absorbed
in the gut and are passed out of the stool. Therefore, diets
containing calcium (i.e. dairy) are likely to decrease urinary
Hyperoxaluria refers to high levels of oxalate in the urine.
Oxalate and calcium combine in the urine to form calcium oxalte
crystals and stones. Oxalates
are originally absorbed from food. Some people have genetic disorders
with extremely high levels of oxalate in the urine. Most,
however, have less severely elevated levels associated with high
oxalate containing diets. These people have Dietary
Hyperoxaluria. In both disorders, limiting the
amounts of high oxalate content foods is recommended. In
addition, consuming dairy products or calcium tablets with meals can
help decrease oxalate absorption. Calcium binds oxalate in the
food preventing it from being absorbed.
Everyone loses citrate into the urine. Citrate prevents stone
from forming. Many people are found to have very low urinary citrate
levels (HYPOCITRITURIA). This is the same citrate or citric
acid as is found in orange juice. After other causes of low
citrate are investigated (i.e. renal tubular acidosis and
hypokalemia) treatment consists of citrate replacement.
Citrate is sold as calcium, sodium, and potassium citrate.
Potassium citrate is the most preferred form if there is no
underlying kidney disease. Lemon juice is a good source of
Stones: Uric acid can
come from high meat intake. Some people with
gout also form
these type of stones. Low protein diets can decrease uric acid
levels. Decreasing alcohol intake can also be beneficial.