Clinical and Experimental Nephrology

, Volume 20, Issue 3, pp 433–442 | Cite as

6-tips diet: a simplified dietary approach in patients with chronic renal disease. A clinical randomized trial

  • Antonio Pisani
  • Eleonora RiccioEmail author
  • Vincenzo Bellizzi
  • Donatella Luciana Caputo
  • Giusi Mozzillo
  • Marco Amato
  • Michele Andreucci
  • Bruno Cianciaruso
  • Massimo Sabbatini
Original Article



The beneficial effects of dietary restriction of proteins in chronic kidney disease are widely recognized; however, poor compliance to prescribed low-protein diets (LPD) may limit their effectiveness. To help patients to adhere to the dietary prescriptions, interventions as education programmes and dietary counselling are critical, but it is also important to develop simple and attractive approaches to the LPD, especially when dietitians are not available. Therefore, we elaborated a simplified and easy to manage dietary approach consisting of 6 tips (6-tip diet, 6-TD) which could replace the standard, non-individualized LPD in Nephrology Units where dietary counselling is not available; hence, our working hypothesis was to evaluate the effects of such diet vs a standard moderately protein-restricted diet on metabolic parameters and patients’ adherence.


In this randomized trial, 57 CKD patients stage 3b-5 were randomly assigned (1:1) to receive the 6-TD (Group 6-TD) or a LPD containing 0.8 g/kg/day of proteins (Group LPD) for 6 months. The primary endpoint was to evaluate the effects of the two different diets on the main “metabolic” parameters and on patients’ adherence (registration number NCT01865526).


Both dietary regimens were associated with a progressive reduction in protein intake and urinary urea excretion compared to baseline, although the decrease was more pronounced in Group 6-TD. Effects on serum levels of urea nitrogen and urinary phosphate excretion were greater in Group 6-TD. Plasma levels of phosphate, bicarbonate and PTH, and urinary NaCl excretion remained stable in both groups throughout the study. 44 % of LPD patients were adherent to the dietary prescription vs 70 % of Group 6-TD.


A simplified diet, consisting of 6 clear points easily managed by CKD patients, produced beneficial effects either on the metabolic profile of renal disease and on patients’ adherence to the dietary plan, when compared to a standard LPD.


Adherence Chronic kidney disease Low-protein diet Protein intake 


Compliance with ethical standards

Conflict of interest

All the authors declare that no conflict of interest exists.


  1. 1.
    Diamond J. Effects of dietary interventions on glomerular pathophysiology. Am J Physiol. 1990;258:F1–8.PubMedGoogle Scholar
  2. 2.
    Premen AJ. Potential mechanisms mediating postprandial renal hyperaemia and hyperfiltration. FASEB J. 1988;2:131–7.PubMedGoogle Scholar
  3. 3.
    Brenner BM. Nephron adaptation to renal injury or ablation. Am J Physiol. 1985;249:F324–37.PubMedGoogle Scholar
  4. 4.
    Hostetter TH, Olson JL, Rennke HG, et al. Hyperfiltration in remnant nephrons: a potentially adverse response to renal ablation. Am J Physiol. 1981;241:F85–93.PubMedGoogle Scholar
  5. 5.
    Kleinknecht C, Salusky I, Broyer M, Gubler MC. Effect of various protein diets on growth, renal function, and survival of uremic rats. Kidney Int. 1979;15:534–41.CrossRefPubMedGoogle Scholar
  6. 6.
    Bellizzi V. Low-protein diet or nutritional therapy in chronic kidney disease? Blood Purif. 2013;36(1):41–6.CrossRefPubMedGoogle Scholar
  7. 7.
    Bellizzi V, Di Iorio B, De Nicola L, Minutolo R, Zamboli P, Trucillo P, Catapano F, Cristofano C, Scalfi L, Conte G, On behalf of the ERIKA Study-group. Very low protein diet supplemented with ketoanalogs improves blood pressure control in chronic kidney disease. Kidney Int. 2007;71:245–51.CrossRefPubMedGoogle Scholar
  8. 8.
    Fouque D, Laville M. Low protein diets for chronic kidney disease in non-diabetic adults. Cochrane Database Syst Rev. 2009;3:CD001892. doi: 10.1002/14651858.CD001892.pub3.PubMedGoogle Scholar
  9. 9.
    Pedrini MT, Levey AS, Lau J, et al. The effect of dietary protein restriction on the progression of diabetic and non-diabetic renal disease: a meta-analysis. Ann Int Med. 1996;124:627–32.CrossRefPubMedGoogle Scholar
  10. 10.
    Brunori G, Viola BF, Parrinello G, et al. Efficacy and safety of a very-low-protein diet when postponing dialysis in the elderly: a prospective randomized multicenter controlled study. Am J Kidney Dis. 2007;49:569–80.CrossRefPubMedGoogle Scholar
  11. 11.
    Milas NC, Nowalk MP, Akpele L. Factors associated with adherence to the dietary protein intervention in the MDRD study. J Am Diet Assoc. 1995;95:11.CrossRefGoogle Scholar
  12. 12.
    Cianciaruso B, Capuano A, D’Amaro E, et al. Dietary compliance to a low protein and phosphate diet in patients with chronic renal failure. Kidney Int. 1989;27(Suppl):S173–6.Google Scholar
  13. 13.
    Miller NH, Hill M, Kottke T, Ockene IS. The multilevel compliance challenge: recommendations for a call to action. A statement for healthcare professionals. Circulations. 1997;95:1085–90.CrossRefGoogle Scholar
  14. 14.
    Paes-Barreto JG, Silva MI, Qureshi AR, Bregman R, Cervante VF, Carrero JJ, Avesani CM. Can renal nutrition education improve adherence to a low-protein diet in patients with stages 3–5 chronic kidney disease? J Ren Nutr. 2013;23(3):164–71.CrossRefPubMedGoogle Scholar
  15. 15.
    Dolecek TA, Olson MB, Caggiula AW, et al. Registered dietitian time requirements in the modificaton of diet in renal disease study. J Am Diet Assoc. 1995;95:1307–12.CrossRefPubMedGoogle Scholar
  16. 16.
    Bellizzi V, Di Iorio BR, Brunori G, De Nicola L, Minutolo R, Conte G, Cianciaruso B, Scalfi L. Assessment of nutritional practice in Italian chronic kidney disease clinics: a questionnaire-based survey. J Ren Nutr. 2010;20(2):82–90.CrossRefPubMedGoogle Scholar
  17. 17.
    Levey AS, Bosch JP, Lewis JB, et al. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Int Med. 1999;130:461–70.CrossRefPubMedGoogle Scholar
  18. 18.
    Maroni BJ, Steinman TI, Mitch WE. A method for estimating nitrogen intake of patients with chronic renal failure. Kidney Int. 1985;27:58–65.CrossRefPubMedGoogle Scholar
  19. 19.
    Cianciaruso B, Pota A, Pisani A, et al. Metabolic effects of two low protein diets in chronic kidney disease stage 4–5—a randomized controlled trial. Nephrol Dial Transplant. 2008;23(2):636–44.CrossRefPubMedGoogle Scholar
  20. 20.
    Thilly N. Low-protein diet in chronic kidney disease: from question of effectiveness to those of feasibility. Nephrol Dial Transplant. 2013;28:2203–5.CrossRefPubMedGoogle Scholar
  21. 21.
    Pan Y, Guo LL, Jin HM. Low-protein diet for diabetic nephropathy: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2008;88:660–6.PubMedGoogle Scholar
  22. 22.
    Levey AS, Greene T, Beck GJ, et al. Dietary protein restriction and the progression of chronic renal disease: what have all of the results of the MDRD study shown? Modification of Diet in Renal Disease Study Group. J Am Soc Nephrol. 1999;10:2426–39.PubMedGoogle Scholar
  23. 23.
    Combe C, Deforges-Lasseur C, Caix J, et al. Compliance and effects of nutritional treatment on progression and metabolic disorders of chronic renal failure. Nephrol Dial Transplant. 1993;8:412–8.PubMedGoogle Scholar
  24. 24.
    Kopple JD. Do low-protein diets retard the loss of kidney function in patients with diabetic nephropathy? Am J Clin Nutr. 2008;88:593–4.PubMedGoogle Scholar
  25. 25.
    Sherman RA, Mehta O. Dietary phosphorus restriction in dialysis patients: potential impact of processed meat, poultry, and fish products as protein sources. Am J Kidney Dis. 2009;54:18–23.CrossRefPubMedGoogle Scholar
  26. 26.
    Piccoli GB, Deagostini MC, Vigotti FN, et al. Which low-protein diet for which CKD patients? An observational, personalized approach. Nutrition. 2014;30(9):992–9.CrossRefPubMedGoogle Scholar
  27. 27.
    Bellizzi V, Chiodini P, Cupisti A, et al. Very low-protein diet plus ketoacids in chronic kidney disease and risk of death during end-stage renal disease: a historical cohort controlled study. Nephrol Dial Transplant. 2015;30(1):71–7.CrossRefPubMedGoogle Scholar

Copyright information

© Japanese Society of Nephrology 2015

Authors and Affiliations

  • Antonio Pisani
    • 1
  • Eleonora Riccio
    • 1
    Email author
  • Vincenzo Bellizzi
    • 2
  • Donatella Luciana Caputo
    • 3
  • Giusi Mozzillo
    • 1
  • Marco Amato
    • 1
  • Michele Andreucci
    • 4
  • Bruno Cianciaruso
    • 1
  • Massimo Sabbatini
    • 1
  1. 1.Chair of Nephrology, Department of Public HealthUniversity Federico II of NaplesNaplesItaly
  2. 2.Division of NephrologyUniversity Hospital “San Giovanni di Dio e Ruggi d’Aragona”SalernoItaly
  3. 3.Division of NephrologyHospital “U. Parini”AostaItaly
  4. 4.Division of NephrologyUniversity “Magna Graecia”CatanzaroItaly

Personalised recommendations