Food-based dietary guidelines in Spain: an assessment of their methodological quality

Food-based dietary guidelines (FBDGs) have been developed to promote healthy diets and prevent chronic diseases. However, the methodological quality of Spanish FBDGs has not been systematically assessed yet. The objective of this review is to identify and assess the methodological quality of Spanish FBDGs, as well as to describe their food guides and key recommendations.

We conducted a systematic search to identify Spanish FBDGs targeted at the general population using multiple sources. Two authors independently screened the references, extracted data, and assessed the quality of the FBDGs using the Appraisal of Guidelines for Research and Evaluation (AGREE) II and the Recommendation Excellence (AGREE-REX) instruments. We performed a descriptive analysis of the FBDGs.

We included 19 FBDGs, published between 2007 and 2019. The median scores for each AGREE II domain were: "scope and purpose" 44% (Q1-Q3: 33-61%); "Stakeholder involvement" 31% (11-44%), "rigor of development" 3% (1-14%); "clarity of presentation" 42% (33-47%), "applicability" 0% (0-6%); and "editorial independence" 0% (0-8%). Six FBDGs (32%; 6/19) were categorized as "recommended with modifications", and the rest (68%; 13/19) as "not recommended". None of the FBDGs scored ≥60% in three or more domains, including the "rigor of development" domain. FBDGs indexed in literature databases scored significantly higher in overall rating than those not indexed (P = 0.023). The majority of FBDGs (74%; 14/19) used the pyramid as a food guide representation with a larger number of food levels (3-7 levels). The majority of FBDGs recommended a daily intake of cereals and grains, vegetables, fruits, olive oil and dairy products; a weekly intake of vegetable and animal proteins; and the occasional and limited intake of other food groups (e.g., ultraprocessed foods).

Overall, the methodological quality of FBDGs is poor showing that only 32% of FBDGs are "recommended for use with modifications". Our results highlight the need to revise, systematize and improve FBDG development processes in Spain.