Table 1. An overview of the inclusion and exclusion criteria for this systematic review.

	Inclusion criteria	Exclusion criteria
Study design	Randomised controlled trial	Observational study design; pilot studies, when a paper clearly stated that the research was a ‘pilot study’
Intervention	Dietary intervention either diet alone (a dietary pattern or dietary supplements) or in combination with lifestyle and/or cognitive strategies	Medical type intervention in conjunction with either a diet/lifestyle/cognitive intervention with undifferentiated results
Control	Control interventions that were not expected to have specific risk-modifying effects; control arms would typically involve no intervention, usual diet or placebo	Studies with no comparator, placebo or control
Diagnosis of MCI	Diagnosis of MCI was necessary by a medical physician or according to internationally accepted and validated classifications or criteria	‘Memory problems’ or ‘self-reported memory complaints’ and no clear diagnosis of MCI; a diagnosis of dementia or any other form of cognitive impairment other than MCI, unless results for MCI participants were presented separately; ’cognitively healthy adults’
Participants	Community dwelling participants; no restrictions made based on sex or age	Individuals who were hospitalised, in a rehabilitation or long-term care facility; participants with psychiatric problems, for example, depression or any significant medical comorbidity, or history of, a comorbid condition that may alter performance on cognitive tests, for example, stroke, head injury, Parkinson’s disease and learning disability

MCI, mild cognitive impairment.