TABLE 1.

Study eligibility criteria

	Inclusion criteria	Exclusion criteria
Study design	Controlled trials •Randomized •Nonrandomized Observational studies •Cross-sectional •Case-control •Nested case-control •Case-cohort •Cohort	•Pre–post trials •Single-arm trials •Acute interventional or postprandial studies1 •In vitro and animal studies •Unpublished studies (for example, conference abstracts and posters) •Case studies or reports
Population	Observational studies and trials •Healthy or generally healthy2 adults (unless case-control design). Controlled trials only •Individuals with prediabetes or T2D	Exclusively unhealthy participants (unless health status is nutrient deficiency related)
Intervention	Whole grain •Whole-grain foods3 •Cereal fiber •Bran •β-glucan and arabinoxylan Biomarkers of whole grain •Alkylresorcinol(s) •Avenacosides(s) •Avenanthramides(s)	Dietary patterns that do not isolate the whole-grain variable (for example, whole-grain intake is not sufficiently isolated from other components in the dietary pattern).
Comparator	No or low whole-grain or whole-grain foods	None
Outcome	Cognition •Cognitive decline •Cognitive function4 •Mild cognitive impairment •Dementia •Alzheimer’s Brain structure and function •Phosphorylated tau proteins or neurofibrillary tangles •Amyloid β plaques Secondary outcomes: •Mood, anxiety, and depression5	Cerebrovascular outcomes (for example, stroke) Movement-related outcomes (for example, balance and falls)

Abbreviation: T2D, type 2 diabetes.

¹Acute interventional studies are defined as 24 h after whole-grain exposure or exposure to one whole-grain–containing meal.

²Generally healthy is defined as <20% of the included population has disease. Hypertension and elevated cholesterol are common conditions found in a generally healthy population. Studies were included if the prevalence of these conditions was found in <20% of the study population.

³Whole-meal, brown bread, coarse bread, wheat, rye, oats, barley, corn/maize, rice, sorghum, millet, quinoa, buckwheat, amaranth, teff, etc.

⁴Cognitive function, as assessed by the following domains: learning and memory, visuospatial and motor function, attention and concentration, language, social cognition and emotion, processing speed, and executive function.

⁵If we did not identify enough papers with the following cognition and brain structure/function outcomes, we considered additional cognition-related outcomes such as mood, anxiety, and depression.