[Effect of protein restriction on deterioration of kidney function]

The results of meta-analyses and of the recent 'modification of diet in renal disease' study show that dietary protein restriction slows down deterioration of renal function in patients with a moderately impaired renal function. However, this effect appears to be less pronounced than previously assumed. Protein restriction probably leads to narrowing of the preglomerular blood vessel, which reduces the raised intraglomerular pressure. The resulting decrease in the filtering glomerular pressure initially leads to a slight loss of renal function, but there after to a decelerated deterioration of renal function. The aim should be a protein intake of 0.6-0.75 g per kg per day. Dietary compliance should not be predicted anamnestically but should be calculated according to the (modified) Maroni equation (protein intake = (0.18 x urinary urea excretion in mmol per 24 hours) + 15 + urinary protein excretion in g per 24 hours). This kind of protein restriction as a rule does not lead to nutritional deficiencies.