Table 1 PICOS criteria for inclusion and exclusion of studies

Population

• Community-dwelling adults aged 18 years and over

• Females and males

• Generally healthy population

• Clinical populations

• Studies of children and adolescent populations

• Studies examining pregnant or lactating women

Interventions

• Observational studies: collected data using single or multiple 24-h recall, food diaries or food frequency questionnaires and assessed diet using scores/indices or data-driven approaches including CA, FA, PCA, RRR

• Studies examining individual dietary nutrients, supplements or foods

• Studies that were not observational studies

Comparisons

• Observational studies: no comparison population

Outcomes

• One or more of the following inflammatory biomarkers:

 ° Adiponectin

 ° C-reactive protein

 ° Fibrinogen

 ° interleukin-6

 ° tumour necrosis factor-alpha

• Any biomarker not listed in the inclusion criteria

Study design

• Cross-sectional studies

• Case-control

• Longitudinal studies

• Literature reviews

• Narrative reviews

• Opinion pieces

• Conference abstracts

• Non-study-based sources

• Intervention studies

• Randomized controlled trials