• Monitoring and Evaluation
    What is the relationship between protein intake and metabolic outcomes in persons with type 1 and type 2 diabetes?
    • Conclusion
       
      The amount of protein consumed at meals has minimal influence on glycemic response, on lipids, on hormones and metabolites, and shows no long-term effect on insulin requirements.  Two single meal studies report an acute insulin response to ingestion of protein.  However, three studies based on higher protein diets (30% of energy from protein) lasting five to twelve weeks showed no significant difference in longer-term insulin response; one study showed a significant decrease in A1C.  As the percentage of energy from protein is increased and the percentage of energy from fat remains constant, the percentage of energy from carbohydrate is decreased, and therefore it is difficult to determine whether higher protein intakes or lower carbohydrate intakes result in significant effects on metabolic outcomes.
       
       
       
       
       
       
    • Grade: II
      • Grade I means there is Good/Strong evidence supporting the statement;
      • Grade II is Fair;
      • Grade III is Limited/Weak;
      • Grade IV is Expert Opinion Only;
      • Grade V is Not Assignable.
      • High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
      • Moderate (B) means we are moderately confident in the effect estimate;
      • Low (C) means our confidence in the effect estimate is limited;
      • Very Low (D) means we have very little confidence in the effect estimate.
      • Ungraded means a grade is not assignable.
    • Search Plan and Results: Protein Intake 2006
       
  • Basic Research
    What is the evidence that protein restriction (with or without amino acid or ketoacid supplementation) is an effective treatment of patients with diabetic nephropathy?
    • Conclusion

      Six positive-quality randomized controlled trials based on lower protein diets in the management of diabetic nephropathy report inconclusive findings; in all six studies this may be a result of poor compliance with reduction in protein intake.  In the two studies that were able to compare protein levels greater than 1.0 g/kg/day with protein intakes of 0.8 g/kg/day or lower, the lower protein diets significantly improved albuminuria but had no significant effects on glomerular filtration rate.  The other four studies found no significant difference between groups in either albumin excretion rate or glomerular filtration rate. In two studies, hypoalbuminemia was associated with an actual protein intake of ~0.7 g/kg/d, but not at a protein intake of ~0.9 g/kg/day. 

    • Grade: II
      • Grade I means there is Good/Strong evidence supporting the statement;
      • Grade II is Fair;
      • Grade III is Limited/Weak;
      • Grade IV is Expert Opinion Only;
      • Grade V is Not Assignable.
      • High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
      • Moderate (B) means we are moderately confident in the effect estimate;
      • Low (C) means our confidence in the effect estimate is limited;
      • Very Low (D) means we have very little confidence in the effect estimate.
      • Ungraded means a grade is not assignable.
    • Search Plan and Results: Protein and Diabetic Nephropathy 2006