Influence of dietary protein on glomerular filtration before and after bariatric surgery

A cohort study

Allon Friedman, Sara Quinney, Margaret Inman, Samer G. Mattar, Zak Shihabi, Sharon Moe

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Background Obesity-associated elevations in glomerular filtration rate (GFR) are common and may play a role in the development of kidney disease, so identifying the underlying mechanism is important. We therefore studied whether reductions in dietary protein intake, which is known to modulate GFR, explain why GFR decreases after bariatric surgery-induced weight loss. Study Design Cohort study with participants as their own controls. Setting & Participants 8 severely obese patients with normal kidney function were recruited from bariatric surgery centers in Indianapolis, IN. All participants were placed on a fixed-protein (50-g/d) diet for 1 week before and after a minimum of a 20-kg weight loss by bariatric surgery and were followed up closely by dieticians for adherence. Predictor Ad lib versus low-protein diet before versus after bariatric surgery. Outcome Measured GFR, using repeated-measures analysis, was used to estimate the independent effects of diet and surgery. Measurement GFR was measured using plasma iohexol clearance. Results A median of 32.9 (range, 19.5-54.4) kg was lost between the first presurgery visit and first postsurgery visit. Dietetic evaluations and urinary urea excretion confirmed that patients generally adhered to the study diet. GFRs on an ad lib diet were significantly higher before compared to after surgery (GFR medians were 144 (range, 114-178) and 107 (range, 85-147) mL/min, respectively; P = 0.01). Although bariatric surgery (-26 mL/min; P = 0.005) and dietary sodium intake (+7.5 mL/min per 100 mg of dietary sodium; P = 0.001) both influenced GFR, consuming a low-protein diet did not (P = 0.7). Limitations Small sample size; mostly white women; possible lack of generalizability. Conclusions The decrease in GFR observed after bariatric surgery is explained at least in part by the effects of surgery and/or dietary sodium intake, but not by low dietary protein consumption.

Original languageEnglish
Pages (from-to)598-603
Number of pages6
JournalAmerican Journal of Kidney Diseases
Volume63
Issue number4
DOIs
StatePublished - 2014

Fingerprint

Bariatric Surgery
Dietary Proteins
Glomerular Filtration Rate
Cohort Studies
Dietary Sodium
Diet
Protein-Restricted Diet
Weight Loss
Iohexol
Dietetics
Nutritionists
Kidney Diseases
Sample Size
Urea
Obesity
Kidney

Keywords

  • bariatric surgery
  • diet
  • glomerular filtration rate
  • glomerular hyperfiltration
  • kidney
  • Obesity
  • protein
  • renal function
  • weight reduction

ASJC Scopus subject areas

  • Nephrology

Cite this

Influence of dietary protein on glomerular filtration before and after bariatric surgery : A cohort study. / Friedman, Allon; Quinney, Sara; Inman, Margaret; Mattar, Samer G.; Shihabi, Zak; Moe, Sharon.

In: American Journal of Kidney Diseases, Vol. 63, No. 4, 2014, p. 598-603.

Research output: Contribution to journalArticle

@article{e6b522f5adb543b69fef6b565ec9e9ef,
title = "Influence of dietary protein on glomerular filtration before and after bariatric surgery: A cohort study",
abstract = "Background Obesity-associated elevations in glomerular filtration rate (GFR) are common and may play a role in the development of kidney disease, so identifying the underlying mechanism is important. We therefore studied whether reductions in dietary protein intake, which is known to modulate GFR, explain why GFR decreases after bariatric surgery-induced weight loss. Study Design Cohort study with participants as their own controls. Setting & Participants 8 severely obese patients with normal kidney function were recruited from bariatric surgery centers in Indianapolis, IN. All participants were placed on a fixed-protein (50-g/d) diet for 1 week before and after a minimum of a 20-kg weight loss by bariatric surgery and were followed up closely by dieticians for adherence. Predictor Ad lib versus low-protein diet before versus after bariatric surgery. Outcome Measured GFR, using repeated-measures analysis, was used to estimate the independent effects of diet and surgery. Measurement GFR was measured using plasma iohexol clearance. Results A median of 32.9 (range, 19.5-54.4) kg was lost between the first presurgery visit and first postsurgery visit. Dietetic evaluations and urinary urea excretion confirmed that patients generally adhered to the study diet. GFRs on an ad lib diet were significantly higher before compared to after surgery (GFR medians were 144 (range, 114-178) and 107 (range, 85-147) mL/min, respectively; P = 0.01). Although bariatric surgery (-26 mL/min; P = 0.005) and dietary sodium intake (+7.5 mL/min per 100 mg of dietary sodium; P = 0.001) both influenced GFR, consuming a low-protein diet did not (P = 0.7). Limitations Small sample size; mostly white women; possible lack of generalizability. Conclusions The decrease in GFR observed after bariatric surgery is explained at least in part by the effects of surgery and/or dietary sodium intake, but not by low dietary protein consumption.",
keywords = "bariatric surgery, diet, glomerular filtration rate, glomerular hyperfiltration, kidney, Obesity, protein, renal function, weight reduction",
author = "Allon Friedman and Sara Quinney and Margaret Inman and Mattar, {Samer G.} and Zak Shihabi and Sharon Moe",
year = "2014",
doi = "10.1053/j.ajkd.2013.11.012",
language = "English",
volume = "63",
pages = "598--603",
journal = "American Journal of Kidney Diseases",
issn = "0272-6386",
publisher = "W.B. Saunders Ltd",
number = "4",

}

TY - JOUR

T1 - Influence of dietary protein on glomerular filtration before and after bariatric surgery

T2 - A cohort study

AU - Friedman, Allon

AU - Quinney, Sara

AU - Inman, Margaret

AU - Mattar, Samer G.

AU - Shihabi, Zak

AU - Moe, Sharon

PY - 2014

Y1 - 2014

N2 - Background Obesity-associated elevations in glomerular filtration rate (GFR) are common and may play a role in the development of kidney disease, so identifying the underlying mechanism is important. We therefore studied whether reductions in dietary protein intake, which is known to modulate GFR, explain why GFR decreases after bariatric surgery-induced weight loss. Study Design Cohort study with participants as their own controls. Setting & Participants 8 severely obese patients with normal kidney function were recruited from bariatric surgery centers in Indianapolis, IN. All participants were placed on a fixed-protein (50-g/d) diet for 1 week before and after a minimum of a 20-kg weight loss by bariatric surgery and were followed up closely by dieticians for adherence. Predictor Ad lib versus low-protein diet before versus after bariatric surgery. Outcome Measured GFR, using repeated-measures analysis, was used to estimate the independent effects of diet and surgery. Measurement GFR was measured using plasma iohexol clearance. Results A median of 32.9 (range, 19.5-54.4) kg was lost between the first presurgery visit and first postsurgery visit. Dietetic evaluations and urinary urea excretion confirmed that patients generally adhered to the study diet. GFRs on an ad lib diet were significantly higher before compared to after surgery (GFR medians were 144 (range, 114-178) and 107 (range, 85-147) mL/min, respectively; P = 0.01). Although bariatric surgery (-26 mL/min; P = 0.005) and dietary sodium intake (+7.5 mL/min per 100 mg of dietary sodium; P = 0.001) both influenced GFR, consuming a low-protein diet did not (P = 0.7). Limitations Small sample size; mostly white women; possible lack of generalizability. Conclusions The decrease in GFR observed after bariatric surgery is explained at least in part by the effects of surgery and/or dietary sodium intake, but not by low dietary protein consumption.

AB - Background Obesity-associated elevations in glomerular filtration rate (GFR) are common and may play a role in the development of kidney disease, so identifying the underlying mechanism is important. We therefore studied whether reductions in dietary protein intake, which is known to modulate GFR, explain why GFR decreases after bariatric surgery-induced weight loss. Study Design Cohort study with participants as their own controls. Setting & Participants 8 severely obese patients with normal kidney function were recruited from bariatric surgery centers in Indianapolis, IN. All participants were placed on a fixed-protein (50-g/d) diet for 1 week before and after a minimum of a 20-kg weight loss by bariatric surgery and were followed up closely by dieticians for adherence. Predictor Ad lib versus low-protein diet before versus after bariatric surgery. Outcome Measured GFR, using repeated-measures analysis, was used to estimate the independent effects of diet and surgery. Measurement GFR was measured using plasma iohexol clearance. Results A median of 32.9 (range, 19.5-54.4) kg was lost between the first presurgery visit and first postsurgery visit. Dietetic evaluations and urinary urea excretion confirmed that patients generally adhered to the study diet. GFRs on an ad lib diet were significantly higher before compared to after surgery (GFR medians were 144 (range, 114-178) and 107 (range, 85-147) mL/min, respectively; P = 0.01). Although bariatric surgery (-26 mL/min; P = 0.005) and dietary sodium intake (+7.5 mL/min per 100 mg of dietary sodium; P = 0.001) both influenced GFR, consuming a low-protein diet did not (P = 0.7). Limitations Small sample size; mostly white women; possible lack of generalizability. Conclusions The decrease in GFR observed after bariatric surgery is explained at least in part by the effects of surgery and/or dietary sodium intake, but not by low dietary protein consumption.

KW - bariatric surgery

KW - diet

KW - glomerular filtration rate

KW - glomerular hyperfiltration

KW - kidney

KW - Obesity

KW - protein

KW - renal function

KW - weight reduction

UR - http://www.scopus.com/inward/record.url?scp=84897115390&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84897115390&partnerID=8YFLogxK

U2 - 10.1053/j.ajkd.2013.11.012

DO - 10.1053/j.ajkd.2013.11.012

M3 - Article

VL - 63

SP - 598

EP - 603

JO - American Journal of Kidney Diseases

JF - American Journal of Kidney Diseases

SN - 0272-6386

IS - 4

ER -