The composition of urine is influenced by diet and changes in dietary factors 
have been proposed to modify the risk of recurrent nephrolithiasis. Nutrients 
that have been implicated include calcium, oxalate, sodium, animal protein, 
magnesium and potassium. There is significant evidence showing that a high 
calcium diet is associated with a reduction of lithogenic risk. One of the 
possible mechanisms to explain this apparent paradox is that the higher intake 
of calcium in the intestine binds with dietary oxalate, reducing its absorption 
and urinary excretion. Oxalate from the diet seems to provide only a small 
contribution to excretion and dietary restriction is appropriate only in those 
with hyperoxaluria and hyperabsorption. Observational studies have shown a 
positive and independent association between sodium intake and the formation of 
new kidney stones. Consumption of animal protein creates an acid load that 
increases urinary excretion of calcium and uric acid and reduced citrate, all 
factors that could participate in the genesis of stones. Potassium-rich foods 
increase urinary citrate because of its alkali content. In prospective 
observational studies, diets rich in magnesium were associated with a lower risk 
of kidney stone formation in men. In conclusion, diet is a key element in the 
management of the patient with kidney stones but always subordinated to present 
metabolic risk factors.