Kidney stone diseases occur in 15–17% of the population in northeast Thailand and it is an important
public health problem 1, 2. High concentrations of
calcium carbonate in water and a low-nutrient diet are
contributing factors to this disease 1. Kidney stones
are commonly composed of calcium oxalate monohydrate (COM), especially in the form of COM microcrystals 3–5. COM is the most thermodynamically
stable form of calcium oxalate (CaOx) at room temperature 4, 6. Ingesting foods such as spiny pigweed
( Amaranthus lividus) and cocoa ( Theobroma cacao)
which contain high oxalic acid causes the formation of
CaOx crystals in urine. These crystals are generally in
the form of COM. Humans normally have biological
control mechanisms to prevent COM crystallization in
the urine by inducing inhibitors that decrease nucleation, growth, and aggregation of COM crystals 3, 7. In
particular, inhibitors in urine will transform COM to
calcium oxalate dihydrate (COD)