Abstract

Both a high dietary oxalate intake and increased gastrointestinal absorption can lead to elevated urinary oxalate, a risk factor for kidney stone formation. Numerous studies have assessed whether daily ingestion of a probiotic containing oxalate-degrading bacteria can reduce urinary oxalate/oxalate absorption, but it appears only one previous study assessed whether the simultaneous ingestion of oxalate-degrading probiotic bacteria consumed with an oxalate load can exert this effect. This was assessed in the present study in a population of 11 healthy non-stone formers (6 males, 5 females), aged 21 – 37 y, using the probiotic VSL#3^®. A spinach-sweet potato mixture provided an oxalate dose of 534 mg and urine samples were collected for a 22 h period post-oxalate ingestion. An additional objective was to assess the effect of blending oxalate-containing foods on oxalate absorption. The overall results suggested that the spinach and sweet potato provided oxalate of low bioavailability. Changing the texture of these foods by blending did not have an effect on oxalate absorption nor was VSL#3^® effective in reducing urinary oxalate levels. VSL#3^® may have been more effective if the oxalate dose had been provided in a more bioavailable form leading to a higher initial oxalate absorption/urinary oxalate excretion.

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