Protein restriction, glomerular filtration rate and albuminuria in patients with type 2 diabetes mellitus: a randomized trial

Abstract

Objective: Protein restriction delays the progression of non-diabetic and type 1 diabetic renal disorders. This study assessed whether protein restriction delays the onset or early progression of renal disorders in type 2 diabetes. Design: Randomized controlled trial. Outcomes were albuminuria (mg=24 h) and, as an estimate of the glomerular filtration rate, cimetidine-influenced creatinine clearance. Setting: Primary care. Subjects: Patients with type 2 diabetes and microalbuminuria or at least detectable albuminuria, or a diabetes duration > 5 y. Interventions: The experimental group received dietary counselling on protein restriction (n ¼ 63); a control group (n ¼ 68) received the usual dietary advice. The duration of intervention and follow-up was 28 AE 7 months. Results: After 6 months, protein intake differed only by 0.08 g=kg=day between the study groups. Subsequently, this difference decreased and eventually disappeared. An initial effect of protein restriction on albuminuria in favor of the experimental group was not sustained, and the glomerular filtration rate decreased in the experimental group at a 1.6 AE 2.2 ml=min=1.73 m 2 y lower rate than in the control group (P ¼ 0.5). Comparison of patients in the experimental group with a decrease in protein intake of at least 0.20 g=kg=day, with controls with no decrease, indicated a similarly small and insignificant effect on glomerular filtration rate. Conclusions: It is concluded that, in the longer term prevention or delay of renal damage in patients with type 2 diabetes, protein restriction is neither feasible nor efficacious.

Long-term effects of advice to consume a high-protein, low-fat diet, rather than a conventional weight-loss diet, in obese adults with Type 2 diabetes: one-year follow-up of a randomised trial

“…In the present study there were no changes in urinary albumin excretion in either group. Cross-sectional [41] and clinical studies [42] in people with diabetes have not shown an association between protein intake and albumin excretion nor a beneficial effect of chronic protein restriction on the course of albuminuria or on prevention/delaying of renal damage. Similarly, Skov and co-workers [43] found no changes in urinary albumin excretion between obese, healthy subjects consuming as much as they wanted of either a low-fat, high-protein or low-protein diet (25% vs 12% of energy as protein) over 6 months, and that changes in urinary albumin excretion were inversely correlated with dietary protein intake.…”

Diabetic Kidney Disease: A Report From an ADA Consensus Conference

“…An increasing body of evidence suggests that dietary pattern intake rather than a sole focus on individual nutrients may offer a more practical approach to dietary management of chronic diseases (122-124). (126)(127)(128)(129)(130)(131)(132)(133).Theeffectsofalow-protein (daily intake of 0.6 g protein/kg ideal body weight), low-phosphorus (500-1,000 mg/day) diet were compared with those of a control diet containing $1.0 g protein/kg ideal body weight per day and $1,000 mg phosphorus per day in 35 patients with type 1 diabetes and DKD. Study participants on the lowprotein, low-phosphorus diet had a slower rate of decline in iothalamate GFR over the course of the study.…”

Predictors for Reporting of Dietary Assessment Methods in Food-based Randomized Controlled Trials over a Ten-year Period

“…Tables 1 and 2 display the detail of each of the studies (by size of the study) that did report a dietary assessment method. In total 50 studies (20.6%) did not report the dietary assessment method used (Janatuinen et al, 1995;Sacks et al, 1995;Conlin et al, 2000;Fan et al, 2000;Kauwell et al, 2000;Knopp et al, 2000;Vuksan et al, 2000;Gregory et al, 2001;Lietz et al, 2001;Moore et al, 2001;Svetkey et al, 2001;Vollmer et al, 2001;Janatuinen et al, 2002;Pijls et al, 2002;Shankar et al, 2002;Vicennati et al, 2002;Allison et al, 2003, Berg et al, 2003Engstrom et al, 2003;Facchini et al, 2003;Gluck and Gebbers, 2003;Hadley et al, 2003;Hoyt et al, 2003;Khan et al, 2003;Upritchard et al, 2003;Vozzo et al, 2003;Wolfe et al, 2003;Xiao et al, 2003; Writing group of the PREMIER Collaborative Research Group, 2003;Chen et al, 2004;Maubach et al, 2004;McGuire et al, 2004;Miyashita et al, 2004;Parra et al, 2004;Sagara et al, 2004;Westerterp-Plantenga et al, 2004;Davey Smith et al, 2005;Svetkey et al, 200...…”

“…Similarly, the FFQ method may also be administered by the above means but can also vary significantly in the number of food items or food groups included with nested food groups appearing to be better suited to this method (Thompson et al, 2002). The number of food groups overall and the portion size associated with them is also likely to influence not only the duration of the assessment itself and in turn the quality of the responses given with (Sacks et al, 1995, Conlin et al, 2000, Knopp et al, 2000, Pijls et al, 2002, Allison et al, 2003, Berg et al, 2003, Facchini et al, 2003, Gluck and Gebbers, 2003, Hadley et al, 2003, Hoyt et al, 2003, Upritchard et al, 2003, Writing group of the PREMIER Collaborative Research Group, 2003, Chen et al, 2004, McGuire et al, 2004, Westerterp-Plantenga et al, 2004, Lejeune et al, 2005, Davey Smith et al, 2005, Benito et al, 2006, Han-Geurts et al, 2007, Cheskin et al, 2008, Due et al, 2008, Sathiaraj et al, 2008.…”

“…Although it was hypothesized that newer studies would utilize technology for dietary assessment more so than older ones, this was not found to be the case x 2 0.487 (p D 0.485). Writers of the publications also appeared to have assumed that the (Janatuinen et al, 1995, Sacks et al, 1995, Conlin et al, 2000, Fan et al, 2000, Vuksan et al, 2000, Kauwell et al, 2000, Knopp et al, 2000, Gregory et al, 2001, Lietz et al, 2001, Janatuinen et al, 2002, Pijls et al, 2002, Shankar et al, 2002, Vicennati et al, 2002, Vozzo et al, 2003, Khan et al, 2003, Engstrom et al, 2003, Hadley et al, 2003, Xiao et al, 2003, Allison et al, 2003, Wolfe et al, 2003, Berg et al, 2003, Facchini et al, 2003, Gluck and Gebbers, 2003, Hoyt et al, 2003, Writing group of the PREMIER Collaborative Research Group, 2003, Upritchard et al, 2003, Westerterp-Plantenga et al, 2004, Miyashita et al, 2004, Parra et al, 2004, Sagara et al, 2004, Maubach et al, 2004, Chen et al, 2004, Davey Smith et al, 2005, Derouiche et al, 2005, McGuire et al, 2004, Pieterse et al, 2005, Shankar et al, 2005, Lejeune et al, 2005, Benito et al, 2006<...>…”