Effect of Replacing Animal Protein with Plant Protein on Glycemic Control in Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract

Previous research on the effect of replacing sources of animal protein with plant protein on glycemic control has been inconsistent. We therefore conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effect of this replacement on glycemic control in individuals with diabetes. We searched MEDLINE, EMBASE, and Cochrane databases through 26 August 2015. We included RCTs ≥ 3-weeks comparing the effect of replacing animal with plant protein on HbA1c, fasting glucose (FG), and fasting insulin (FI). Two independent reviewers extracted relevant data, assessed study quality and risk of bias. Data were pooled by the generic inverse variance method and expressed as mean differences (MD) with 95% confidence intervals (CIs). Heterogeneity was assessed (Cochran Q-statistic) and quantified (I2-statistic). Thirteen RCTs (n = 280) met the eligibility criteria. Diets emphasizing a replacement of animal with plant protein at a median level of ~35% of total protein per day significantly lowered HbA1c (MD = −0.15%; 95%-CI: −0.26, −0.05%), FG (MD = −0.53 mmol/L; 95%-CI: −0.92, −0.13 mmol/L) and FI (MD = −10.09 pmol/L; 95%-CI: −17.31, −2.86 pmol/L) compared with control arms. Overall, the results indicate that replacing sources of animal with plant protein leads to modest improvements in glycemic control in individuals with diabetes. Owing to uncertainties in our analyses there is a need for larger, longer, higher quality trials. Trial Registration: ClinicalTrials.gov registration number: NCT02037321.

Comparison of the effects of diets high in animal or plant protein on metabolic and cardiovascular markers in type 2 diabetes: A randomized clinical trial

“…The present study therefore supports the use of high AP or PP diets in the short term. In view of the unfavourable results with AP as compared to PP in epidemiological studies, [4][5][6][7][8]11,50 explanations targeting differences in behaviour, phytochemical content, carbohydrate and fat quality or other confounders might deserve attention.…”

“…[3][4][5] High intake of animal protein (AP) in general has also been found to be associated with increased risk of T2DM, which was not observed with PP [6][7][8] ; however, whey protein intake was shown to improve meal-related metabolism in people with T2DM in several studies. 9,10 A meta-analysis of intervention studies replacing AP with PP in people with T2DM also showed a slight improvement in glycated haemoglobin (HbA1c) by 0.15% 11 ; however, increased intake of plant products will also increase fibre and phytochemical intakes, and the differences may not relate to differences in amino acid composition of the proteins per se. 12 Typically, PP contains lower levels of the branched chain amino acids (BCAA) leucine, isoleucine and valine and of the sulphur amino acid methionine as compared with AP.…”

Can pulses play a role in improving cardiometabolic health? Evidence from systematic reviews and meta‐analyses

“…Suggested reasons for this observed CVD risk benefit may be related to specific nutrients and properties found in legumes (i.e., fiber, magnesium, potassium, folate, phytochemicals, low GI, etc. ), observed benefits of non‐soy legumes on various cardiometabolic risk factors (see below), and, potentially, the replacement of certain foods with legumes (i.e., red meat and high‐GI foods) …”

Replacing Animal-Based Proteins with Plant-Based Proteins Changes the Composition of a Whole Nordic Diet—A Randomised Clinical Trial in Healthy Finnish Adults

“…Higher protein intake, particularly from plant-based sources, may also be associated with attenuated inflammatory burden in aging populations [16]. In diabetics, replacing animal protein with plant proteins may help to improve glycaemic control and prevent the onset of risk factors associated with CVD [14,17,18].…”