A randomized trial of low-protein diet in type 1 and in type 2 diabetes mellitus patients with incipient and overt nephropathy

J Ren Nutr. 2005 Oct;15(4):398-406. doi: 10.1053/j.jrn.2005.07.003.


Objective: The efficacy of a low-protein diet in the secondary prevention of diabetic nephropathy is not established in patients with type 1 or type 2 diabetes mellitus. To determine whether a low-protein diet slows the decrease in glomerular filtration rate (GFR) and decreases the albumin excretion rate (AER) in diabetic patients with incipient and overt nephropathy, we performed a 2-year prospective, randomized controlled trial comparing the effects of a low-protein diet (0.8 g/kg/day) with a usual-protein diet.

Setting and patients: The study was conducted in a University hospital and included 63 type 1 and type 2 diabetic patients with either incipient or overt nephropathy and mild renal failure (prestudy GFR, 80 +/- 20 mL/min). The primary outcome measures were decreased in GFR and 24-hour AER.

Results: In the low-protein-diet group, patients were younger (52 +/- 12 versus 63 +/- 9 years old) and more often were type 2 diabetic. During the follow-up period, according to dietary records the low-protein-diet group consumed 16% +/- 3% of total caloric intakes as compared with 19% +/- 4% in the usual-protein-diet group (P < .02), but 24-hour urinary urea excretions did not differ between the two groups. The 2-year GFR decrease was 7 +/- 11 mL/min in the low-protein-diet group and 5 +/- 15 mL/min in the usual-protein-diet group (P = not significant). AER did not increase significantly in the two diet groups during the follow-up period. Blood pressure and glycemic control were similar in the two groups all along the study. The decrease in GFR and AER were also similar in 6 compliant patients according to dietary records and to 24-hour urinary urea excretions from the low-protein-diet group and in 12 patients from the usual-protein-diet group.

Conclusions: A 2-year low-protein diet did not alter the course of GFR or of AER in diabetic patients with incipient or overt nephropathy receiving renin-angiotensin blockers with strict blood pressure control.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Albuminuria / urine
  • Blood Pressure
  • Diabetes Mellitus, Type 1 / diet therapy*
  • Diabetes Mellitus, Type 2 / diet therapy*
  • Diabetic Nephropathies / diet therapy*
  • Diabetic Nephropathies / physiopathology
  • Diet Records
  • Diet, Protein-Restricted*
  • Dietary Carbohydrates / administration & dosage
  • Dietary Fats / administration & dosage
  • Energy Intake
  • Glomerular Filtration Rate
  • Glycated Hemoglobin A / analysis
  • Humans
  • Lipids / blood
  • Middle Aged
  • Nutritional Status
  • Prospective Studies
  • Serum Albumin / analysis
  • Surveys and Questionnaires


  • Dietary Carbohydrates
  • Dietary Fats
  • Glycated Hemoglobin A
  • Lipids
  • Serum Albumin