N-of-1 Clinical Trials in Nutritional Interventions Directed at Improving Cognitive Function

Abstract

Longer life expectancy has led to an increase in the prevalence of age-related cognitive decline and dementia worldwide. Due to the current lack of effective treatment for these conditions, preventive strategies represent a research priority. A large body of evidence suggests that nutrition is involved in the pathogenesis of age-related cognitive decline, but also that it may play a critical role in slowing down its progression. At a population level, healthy dietary patterns interventions, such as the Mediterranean and the MIND diets, have been associated with improved cognitive performance and a decreased risk of neurodegenerative disease development. In the era of evidence-based medicine and patient-centered healthcare, personalized nutritional recommendations would offer a considerable opportunity in preventing cognitive decline progression. N-of-1 clinical trials have emerged as a fundamental design in evidence-based medicine. They consider each individual as the only unit of observation and intervention. The aggregation of series of N-of-1 clinical trials also enables population-level conclusions. This review provides a general view of the current scientific evidence regarding nutrition and cognitive decline, and critically states its limitations when translating results into the clinical practice. Furthermore, we suggest methodological strategies to develop N-of-1 clinical trials focused on nutrition and cognition in an older population. Finally, we evaluate the potential challenges that researchers may face when performing studies in precision nutrition and cognition.

The Effect of Healthy Diet on Cognitive Performance Among Healthy Seniors – A Mini Review

“…These personalized dietary interventions can then contribute to higher adherence to healthy diet as it has been already indicated in the section “Introduction.” Research goes even further and suggests conducting N-of-1 trials that would explore nutrition and cognitive performance in an individual. The reason is that each individual responds differently to dietary components, which are influenced by the interplay between various factors, such as environment, society, metabolism and genetics ( Soldevila-Domenech et al, 2019 ).…”

“…The study protocols, e.g., ( Mumme et al, 2019 ), multi-domain intervention studies, e.g., ( Lehtisalo et al, 2017 ; Rosenberg et al, 2018 ), the studies with different age range of seniors, e.g., ( Kita et al, 2018 ), the studies with cognitively impaired seniors, e.g., ( Baleztena et al, 2018 ; Mazza et al, 2018 ), and cross-over randomized control study ( Dodd et al, 2019 ), the review studies, e.g., ( Vauzour et al, 2017 ; Chen et al, 2019 ; Cremonini et al, 2019 ; Soldevila-Domenech et al, 2019 ).…”

“…Therefore, there is a sustainable effort to discover alternative, effective, safe, and inexpensive strategies which could contribute to the prevention of dementia and cognitive decline and strive to improve the quality of life of aging population (Livingston et al, 2017;Vauzour et al, 2017;Cremonini et al, 2019). Evidence suggests that healthy diet or nutrition may be one of these preventive strategies (Kita et al, 2018;Mazza et al, 2018;Chen et al, 2019;Dodd et al, 2019;Karstens et al, 2019;Soldevila-Domenech et al, 2019).…”

Exploring the potential for collaborative use of an app-based platform for n-of-1 trials among healthcare professionals that treat patients with insomnia

“…At the end of the trial, outcome measurements for each treatment are compared and a treatment is selected. N-of-1 trials may also be deployed to answer other common treatment investigations, such as whether to begin a treatment, proper dosing [7], disease-related nutrition recommendations [8][9][10], assessing treatment response in people with characteristics (e.g. rare genetic variants) not studied in randomized controlled trials of approved medications [11][12][13], and deprescribing [14], among others.…”

“…Coxeter et al reported the effectiveness of valerian versus placebo in 24 patients with chronic insomnia [15]. Punja et al have described a protocol to assess the effectiveness of melatonin in children (ages [6][7][8][9][10][11][12][13][14][15][16][17] taking medications for ADHD [16]. Nikles et al have described a protocol to assess the effectiveness of melatonin in patients with PD [17].…”