Oxalate and magnesiumalsoplayimportant roles in nephrolithiasis. Calcium oxalate kidney stones are the most prevalent type. Therefore, higher levels of oxalate in urine lead to a higher calcium oxalate supersaturation,andthus toa higher probability of developinga kidney stone [24]. In contrast, magnesium is an inhibitor of calcium oxalate nephrolithiasis, because it complexes with oxalate, reducing its free concentration in urine, and thus preventing the formation of calcium oxalate kidney stones [25]. Although oxalate and magnesium are present in high amounts in chocolate, their urinary excretion was not significantly associated with cocoa consumption. However, the median urinary excretion of magnesium and oxalate was higher in the high cocoa consumption group than in the other three groups.
The lack of correlation between the urinary excretion of magnesium and oxalate and the consumption of cocoa products may be due to the presence of magnesium and oxalate, but not of theobromine, in other types of food, whereas theobromine is present only in cocoa products. Therefore, cocoa products can modify the urinary excretion of both magnesium and oxalate, but their excretion levels are not dependent only on cocoa consumption.