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. 2023 Mar 14;12(1):39.
doi: 10.1186/s13643-023-02209-1.

Saturated fat and human health: a protocol for a methodologically innovative systematic review and meta-analysis to inform public health nutrition guidelines

Bradley C Johnston  1   2 , Dena Zeraatkar  3   4 , Jeremy Steen  5 , Diego Rada Fernandez de Jauregui  6   7 , Hongfei Zhu  8   9 , Mingyao Sun  10 , Matthew Cooper  11 , Malgorzata Maraj  12 , Anna Prokop-Dorner  13 , Boris Castro Reyes  14 , Claudia Valli  14   15 , Dawid Storman  16   17   18 , Giorgio Karam  19 , Joanna Zajac  12 , Long Ge  4   8   9 , Mateusz J Swierz  16   17 , Nirjhar Ghosh  7 , Robin W M Vernooij  20   21 , Yaping Chang  4 , Yunli Zhao  4   22 , Lehana Thabane  4 , Gordon H Guyatt  4   23 , Pablo Alonso-Coello  14   24 , Lee Hooper  25 , Malgorzata M Bala  16   17
Affiliations

Saturated fat and human health: a protocol for a methodologically innovative systematic review and meta-analysis to inform public health nutrition guidelines

Bradley C Johnston et al. Syst Rev. .

Abstract

Background: The health effects of dietary fats are a controversial issue on which experts and authoritative organizations have often disagreed. Care providers, guideline developers, policy-makers, and researchers use systematic reviews to advise patients and members of the public on optimal dietary habits, and to formulate public health recommendations and policies. Existing reviews, however, have serious limitations that impede optimal dietary fat recommendations, such as a lack of focus on outcomes important to people, substantial risk of bias (RoB) issues, ignoring absolute estimates of effects together with comprehensive assessments of the certainty of the estimates for all outcomes.

Objective: We therefore propose a methodologically innovative systematic review using direct and indirect evidence on diet and food-based fats (i.e., reduction or replacement of saturated fat with monounsaturated or polyunsaturated fat, or carbohydrates or protein) and the risk of important health outcomes.

Methods: We will collaborate with an experienced research librarian to search MEDLINE, EMBASE, CINAHL, and the Cochrane Database of Systematic Reviews (CDSR) for randomized clinical trials (RCTs) addressing saturated fat and our health outcomes of interest. In duplicate, we will screen, extract results from primary studies, assess their RoB, conduct de novo meta-analyses and/or network meta-analysis, assess the impact of missing outcome data on meta-analyses, present absolute effect estimates, and assess the certainty of evidence for each outcome using the GRADE contextualized approach. Our work will inform recommendations on saturated fat based on international standards for reporting systematic reviews and guidelines.

Conclusion: Our systematic review and meta-analysis will provide the most comprehensive and rigorous summary of the evidence addressing the relationship between saturated fat modification for people-important health outcomes. The evidence from this review will be used to inform public health nutrition guidelines.

Trial registration: PROSPERO Registration: CRD42023387377 .

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Conflict of interest statement

As part of his start-up funds at Texas A&M University, BCJ received a grant from Texas A&M AgriLife Research (2019–2020) to fund investigator-initiated research related to saturated and polyunsaturated fats. The grant was from Texas A&M AgriLife institutional funds from interest and investment earnings, not a sponsoring organization, industry, or company. These funds were used to support, in part, an overview of systematic reviews addressing saturated fat and health outcomes (under review). Otherwise, these funds were not used to support any work on this project. DRFdJ was on an exchange program to Texas A&M University supported by the requalification of official or contracted university teaching staff grant (RECUALI21/16) from the University of Basque Country and the Spanish Ministry of Universities, funded by the European Union-Next-Generation EU. LH has received funding (to her institution) from WHO to update a Cochrane systematic review on the effects of reducing saturated fat on cardiovascular disease. These recent WHO funds paid for about 60% of LH’s salary. BCJ, MMB, and PAC are GRADE working group members; GG is the Co-Chair of the GRADE working group. Otherwise, authors claim no other relationships or activities that could appear to have influenced the submitted work.

References

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