Relationship between dietary protein intake and serum urea, uric acid and creatinine, and 24-hour urinary creatinine excretion: the BIRNH Study.

Relationships between dietary protein intake of a large free-living group and serum creatinine (Cr), urea and uric acid levels have been studied, based on data obtained from the BIRNH (Belgian Interuniversity Research on Nutrition and Health) study. Highly significant correlations were found in both sexes for total protein, as well as for animal and vegetable protein intake. In a subgroup, the relationship between dietary protein intake and 24-hour urinary Cr excretion has also been studied. The range of +/- 2 SD of the mean for total protein and animal and vegetable protein daily intakes resulted in a calculated range of 24-hour Cr excretion of 430, 317 and 209 mg/24 hours in men and of 192, 169 and 125 mg/24 hours in women, respectively. The 24-hour urinary Cr excretion was significantly influenced by both dietary protein and polyunsaturated fat intake.