Introduction

The human diet is considerably complex and it has been studied in nutritional epidemiology due to the possible influence of dietary aspects on the occurrence of chronic non-communicable diseases [1, 2].

Food consumption can be assessed in several ways, including intake of chemical compounds, foods, food groups, and dietary patterns [3]. Dietary assessment methods include retrospective and prospective methods. All methods have strengths and limitations, so the choice of the most appropriate method will depend on the objective of the evaluator. Among the prospective methods, the most used is the food record. Among the retrospective methods, the 24-hour dietary recall (24h recall) and the food frequency questionnaire (FFQ) are commonly used. The 24h recall assesses short-term diet and the FFQ assesses long-term diet [4].

The assessment of long-term food intake has been widely used under the assumption that the estimation of the usual diet, practiced over weeks, months or years, constitutes a more important exposure factor than the estimation of the actual food intake [5]. In this context, despite the new perspectives of innovative methods of assessing food consumption [2], the FFQ is still used in epidemiological studies to assess the intake of chemical compounds (nutrients, non-nutritional compounds, and others), specific foods or food groups, with low cost and easy administration [6]. The FFQ is composed of a fixed list of foods in which the respondent indicates the consumption of a certain portion of those foods during a certain period of time. As this method depends on the interviewee’s memory, imprecise answers or possible omissions are some disadvantages of the FFQ [5, 7].

The choice of a FFQ should be made carefully and it must consider the objectives and the particularities of the instrument such as type, scope of dietary assessment (global or specific), and administration approach. Furthermore, as the human diet varies according to geographic region, age, and cultural aspects, FFQs need to be specific and validated for the target population [8]. However, depending on the researcher’s objective or goals in clinical practice, elaborating a FFQ can be expensive and unnecessary work, since it is possible to adapt existing questionnaires, followed by a validation for the population studied. However, the instrument must be minimally adequate to the population under evaluation [5].

In a country with continental dimensions like Brazil (8,516,000 km²), divided into five regions, the food particularities of each region present considerable variations derived from cultural roots arising from colonization. A non-systematic review developed by Pedraza and Menezes (2015) [9] was published many years ago with the objective of identifying the studies that developed and/or validated FFQ in Brazil until 2013. The authors discussed the FQQ validation methods and its main results, analyzing the most appropriate instruments and verifying the usefulness of such FFQs in the country.

In recent years, FFQs have been constructed and validated in Brazil for specific populations such as children [10], adolescents [10–12], adults [12, 13], athletes [14] and individuals with specific clinical conditions [15, 16]. Considering the diversity of FFQs constructed, we observed the need to map the FFQs that exist in Brazil to date, identifying the objectives, particularities, and the population for which they are intended. This mapping will help Brazilian researchers and clinicians in consulting the existence of specific FFQs according to their needs. A preliminary search of PubMed/MEDLINE, Cochrane Database of Systematic Reviews, and JBI Evidence Synthesis was performed and no current or ongoing systematic or scoping reviews on the topic were identified. Thus, this scoping review intends to update the identification of published FFQs, which were developed and validated in Brazil, using a systematic methodology capable of answering a comprehensive research question.

Materials and methods

The proposed scoping review will be conducted according to the approach proposed by the JBI (formerly known as Joanna Briggs Institute) for scoping reviews [17] and the PRISMA extension for Scoping Reviews (PRISMA-ScR) (S1 Checklist) [18]. Our protocol is registered through the Open Science Framework (doi 10.17605/OSF.IO/G5J3K).

Eligibility criteria

To construct the research question, the Population-Concept-Context (PCC) framework was used for search strategy and defined as P—not applicable (open), C—food frequency questionnaire, and C—Brazil (Table 1).

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Table 1. PCC framework used in the scoping review.

https://doi.org/10.1371/journal.pone.0294450.t001

Considering the nature of the research question, the population of the PCC framework was not applicable (open). Other types of dietary assessment methods or studies with populations from other countries will be excluded.

Search strategy

The search strategy will aim to locate both published and unpublished studies. Studies performed up to February 2023 will be included. Considering the comprehensive nature of this review, no restrictions of date or language will be imposed in the search strategy.

An initial search in PubMed/MEDLINE, Embase, LILACS, Web of Science (ISI), Scopus, and Google Scholar was performed to identify some reports on the topic. Key words and indexing terms of these reports were used to develop a search strategy for PubMed/MEDLINE, Embase, LILACS and Google Scholar Databases (see example in Table 2). The search equations will be adapted for each database and/or information source included.

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Table 2. Search strategy for PubMed/MEDLINE database.

https://doi.org/10.1371/journal.pone.0294450.t002

Sources of unpublished studies to be searched include national theses and dissertation databases. In addition, manual searches of the reference lists of the included articles will be performed to identify additional studies that were not retrieved through the search equations.

Data extraction

Two independent reviewers will perform data extraction using a form developed by the authors according to the model (Table 3 and S1 File). The extracted data will include details about the concept, context, study methods, and key findings relevant to the review question.

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Table 3. Description of variables for data extraction.

https://doi.org/10.1371/journal.pone.0294450.t003

The preliminary data extraction form will be modified and revised as necessary for application in the scoping review. Any disagreements that arise between reviewers will be resolved by a third reviewer. If necessary, article authors will be contacted to request missing or additional data.

Discussion

This review will use a systematic search strategy and the JBI standardized methodology for scoping reviews. In addition, it will consider articles from a broad range of settings, interventions, and study designs that will lead to insights for a wide array of healthcare research audiences.

It will be beneficial to map the existing FFQs in Brazil, a huge and culturally diverse country. This review will contribute to the design of research on food consumption, facilitating the identification of existing FFQs in the area of interest for the study, encouraging production or adaptation to specific populations, foods/food groups, and nutrients, or reducing unnecessary FFQ development. Furthermore, the results of this review will guide the use of specific FFQs in the individual or group clinical assessment of habitual food consumption in Brazil.

The limitations of this study are related to the comprehensive and exploratory nature of the scoping review. In case of necessary changes to this protocol after publication, the date, nature, and justification of such changes will be provided.

Supporting information