Table 2.

PICOS table, showing the inclusion and exclusion criteria for study population, intervention, comparator, outcome/s, and study design.

PICOS	Inclusion	Exclusion
Population	Human Healthy community dwelling sedentary individuals. Sedentary individuals initiating a structured physical activity or exercise program. Recreational and competitive active adults (18–60 years). Male and female biological sex.	Animals and in vitro studies. Infants or children. Pregnancy or lactating. Sedentary individuals with non-communicable disease risk or established disease (i.e., cardiometabolic risk factors or established cardiovascular diseases, diabetes mellitus, and/or metabolic syndrome). Diagnosed disease or syndrome states (i.e., all clinical populations). Population adhering to dietary modifications and/or dietary supplementation, other than pre-/pro-/syn-biotic intervention.
Intervention	Acute and prolonged provisions of prebiotic/s, probiotic/s, and synbiotic blends (i.e., prebiotic + probiotic, with or without other nutrient inclusion) (e.g., vitamins, minerals, lipids, phytochemicals, and/or volatiles). With and without monitored and/or structures physical active and/or exercise program. Dietary control (monitoring or provisions).	Dietary interventions not containing acute and prolonged provisions of prebiotic/s, probiotic/s, and synbiotic blends. Acute and prolonged provisions of prebiotic/s, probiotic/s, and synbiotic blends that contain a pharmaceutics grade product or compound.
Comparator	Placebo group Control group	No placebo or control
Outcome	Gastrointestinal integrity markers: e.g., I-FABP, Claudin-3, dual sugars test for permeability, and other markers proposed to assess gastrointestinal epithelial integrity. Gastrointestinal functional markers: e.g., gastric aspiration, C13 breath test, OCTT, EGG, pH pill monitoring, H2 and CH4 malabsorption challenge. Systemic markers of compromised gastrointestinal integrity: e.g., CRP, systemic inflammatory response cytokine profile, systemic endotoxin profile (e.g., LPS, gram-negative endotoxin, ant-endotoxin antibody, sCD14, and/or LBP), systemic microbial identification (e.g., gene sequencing determination), immune cell functional responses and/or counts. Gastrointestinal signs and symptoms: e.g., stool habits and texture, QoL, and/or symptoms. Gastrointestinal microbiota: e.g., bacterial taxonomy (ASV or OTU) including α-diversity and relative abundance, bacterial functional markers including SCFA concentration (e.g., butyrate, propionate, and/or acetate).
Study design	RCT or randomized crossover trial.	All other study designs

ASV, Amplicon sequence variant; CRP, c-reactive protein; EGG, electrogastrography; I-FABP, Intestinal fatty acid binding protein; LBP, lipopolysaccharide binding protein; LPS, lipopolysaccharide; OCTT, orocecal transit time; OTU, operational taxonomic units; QoL, quality of life; sCD14, soluble CD14; SCFA, short chain fatty acid; RCT, randomized control trial.