Source: Resuscitation  |  Posted 9 years ago

Switching from a standard Western to a mixed or vegetarian diet may reduce the risk of calcium oxalate crystallisation, according to a small study.

In an effort to determine whether specific diet modifications affect the risk of calcium oxalate crystallisation, Roswitha Siener and Albrecht Hesse from the division of experimental urology, department of urology, University of Bonn, Bonn, Germany recruited 10 healthy male volunteers to follow specific diet recommendations. The participants followed a self-selected diet for 14 days followed by three different diets for five days each. The diets consisted of a standard Western type diet, a normal mixed diet and an ovo-lacto-vegetarian diet.

The investigators regularly collected and tested the urine of the participants during each diet period. They determined that the risk of calcium oxalate crystallisation was highest while patients were following the self-selected and Western diets. While on the normal mixed diet, relative supersaturation with calcium oxalate diminished by an average of 58 percent, compared with the Western diet (p<0.05). This reduction was due to a significant decline in urinary calcium and uric acid excretion as well as a significant increase in urinary volume, pH and citrate excretion.

With the vegetarian diet, there were further increases in urinary pH, citrate excretion and magnesium excretion as well as further decreases in calcium excretion compared with the mixed diet. However, these changes did not confer an added reduction in calcium oxalate crystallisation risk because the vegetarian diet was also associated with a significant 30% increase in urinary oxalate (p<0.05).

According to the authors, changing dietary habits from normal to mixed or vegetarian may reduce the risk of calcium oxalate crystallisation. However, since urinary oxalate excretion occurred with the vegetarian diet, such a diet should be accompanied by adequate calcium intake in patients with mild hyperoxaluria.