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Page 39
| What Causes Kidney Stones? |
| A stone can form only when urine is supersaturated with one or more of its constituent crystals, either from too much of that substance, or too little of the protective proteins from the urine and mucosa. |
| Supersaturation means that the concentration of a stone-forming salt, such as calcium oxalate, exceeds its solubility in urine. The substance "snows," much like when a 100-percent saturation of water in the air becomes rain or snow. The urine of most normal people is supersaturated with calcium oxalate, so, in principle, all people can form such stones. Normal urine is not supersaturated with uric acid, cystine or struvite. |
| Any conditions that raise calcium oxalate supersaturation raise the risk of calcium oxalate stones, and any conditions that lessen the urinary tract "emulsifiers" also raise the risk of these, and in fact, any stones. |
| Many disorders can raise the levels of both calcium and oxalates. Further, hyperparathyroidism, renal tubular acidosis, sarcoidosis, vitamin D intoxication and "idiopathic" hypercalciuria all are causes of hypercalciuria (elevated urine calcium). Elevated oxalates (or hyperoxaluria) may be due to overproduction from hereditary disorders of metabolism or be acquired from intestinal disease or diet. |
| The causes of diminished production of the protective urinary proteins is unknown, but in my opinion, the chronic skin and mucosal hyposecretion that results from adrenal stress as well as from certain decongestants and allergy medications can also contribute to kidney stones. |
| Doctors do not always know what causes a stone to form. While certain foods may promote stone formation in people who are susceptible, scientists do not believe that eating any specific food causes stones to form in people who are not susceptible. |
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