Table 3.

Challenges of traditional clinical trials testing the efficacy of nutritional interventions for dementia prevention.

Main challenges	Risks or consequences
Study Design
Blinding	Control group contamination
Adherence to the intervention	Poor sustainability of the proposed intervention
Dropout rates	Decreased statistical power
	Confounding and selection biases post-baseline
Dietary assessment	Misreporting and underreporting concerns due to memory difficulties of participants experiencing cognitive decline Participant and researcher burden
Cognition as an outcome
Short interventions	Incapacity to assess effects on primary outcomes (e.g., dementia incidence) Limited clinical relevance of minor cognitive changes
Cognitive assessment tools	Poor sensitivity of cognitive tests to detect subtle changes in cognition
Target population
Heterogeneity of target population   Strict inclusion/exclusion criteria	Inconclusive results Healthy subsample of the target population Potential effects of disclosing to participants a high risk of developing AD