The relationship between dietary intake and urinary excretion of sodium, potassium, calcium and magnesium: Belgian Interuniversity Research on Nutrition and Health.

During an epidemiological survey, the dietary intake and urinary excretion of sodium, potassium, calcium and magnesium were measured by means of the 24 h food record method and a 24 h urine collection in 2,112 men and 1,943 women. Significant correlations (P less than 0.001) were found between dietary intake and urinary excretion of the above cations in men and women by univariate analysis and after adjustment for age, height, weight and total caloric intake. Taking into account the difficulty of estimating dietary cation intakes and obtaining complete 24 h urine collections, and the non-coincidence of the 24 h urine collection and the food recording periods, our findings point to a strong positive association between dietary intake and urinary excretion of sodium, potassium, calcium and magnesium. No significant relationship was found between these urinary cations and blood pressure.