Effect of a Portfolio Dietary Pattern on Cardiometabolic Risk: A Systematic Review and Meta-analysis of Controlled Trials

Background: The Portfolio Dietary Pattern, which includes nuts, viscous fiber, plant protein, and plant sterols, has been shown to have a cholesterol-lowering effect similar to that of early statin medications. Despite the endorsement of the Portfolio Dietary Pattern by major international diabetes and cardiovascular guidelines, the European Association for the Study of Diabetes (EASD) guidelines for nutrition therapy have not made any specific recommendations for the Portfolio Dietary Pattern. The present systematic review and meta-analysis using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was thus commissioned by the Diabetes and Nutrition Study Group (DNSG) of the EASD to summarize the available evidence from controlled trials of the effect of the Portfolio dietary pattern on LDL-cholesterol (LDL-C) and other established cardiometabolic risk factors.

Need for proposed research: High quality systematic reviews and meta-analyses of controlled trials represent the highest level of evidence to support dietary guidelines and public health policy development. As dietary guidelines and public health policy have shifted toward food and dietary-pattern based recommendations, there is a need for a systematic review and meta-analysis assessing the pooled effect of the Portfolio Dietary Pattern trials on cholesterol and cardiometabolic risk factors.

Objective: The investigators will conduct a systematic review and meta-analysis to summarize the effect of a Portfolio Dietary Pattern compared to control on lipids and other cardiometabolic risk factors in controlled clinical trials.

Design: The systematic review and meta-analysis will be conducted according to the Cochrane Handbook for Systematic Reviews of Interventions and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

Data sources: MEDLINE, EMBASE, and The Cochrane Central Register of Controlled Trials will be searched using appropriate search terms supplemented by hand searches of references of included studies. Authors will be contacted for applicable missing data.