I am a Postdoctoral Researcher at the Nutrition Research Centre Ireland (NRCI), South East Technological University, and more recently a Marie Skłodowska Curie Action Research Fellow at the Decision Neuroscience Laboratory at the University of Illinois Urbana-Champaign. I am interested in the role of dietary patterns and specific nutrients in maintaining brain health, improving cognitive performance and reducing the risk of Alzheimer’s disease. 

What is the rationale behind your study? 

Omega-3 fatty acids (the building blocks of our cells), carotenoids (plant-based pigments that give fruits and vegetables their bright colours) and vitamin E (one of four essential fat-soluble vitamins) are important parts of a healthy diet. Previous studies have shown that each of these nutrients are important for optimising and maintaining healthy brain function, primarily due to their antioxidant and anti-inflammatory properties (Power et al. 2019, Lloret et al. 2019). However, the combined effects of these nutrients on brain health and cognitive performance in older adults (aged 65+ years) had not been examined to date. This study, the Cognitive impAiRmEnt Study (CARES), aimed to address this research gap. 

Which methods did you use?

Thirty individuals consumed daily a nutritional formulation containing 1g fish oil (430mg DHA and 90mg EPA), 22 mg carotenoids (10mg lutein, 10mg meso-zeaxanthin and 2mg zeaxanthin) and 15mg vitamin E while 30 individuals consumed a placebo (sunflower oil). Omega-3 fatty acid concentrations were quantified in blood using gas chromatography. Carotenoid and vitamin E concentrations were quantified in blood using high performance liquid chromatography. Carotenoids concentrations were also quantified in tissue using the Pharmanex BioPhotonic skin scanner. 

Global cognition was assessed using the Montreal Cognitive Assessment (MoCA, version 7.1) and the Repeated Battery for the Assessment of Neuropsychological Status (RBANS Record form A). Additional assessments of specific cognitive domains were performed using the Cambridge Neuropsychological Test Automated Battery (CANTAB^TM).

Which CANTAB^TM tasks did you use?

We used the motor control task (MOT) to determine comprehension, the spatial working memory task (SWM) to measure working memory, the reaction time task (RTI) to assess attention and the paired associated learning task (PAL) to assess episodic memory. Study assessments took place at a single site (the Nutrition Research Centre Ireland) at baseline and at 12- and 24-month follow up. 

What are your key findings?

The research, published in Clinical Nutrition, showed improvements in working memory performance following nutritional supplementation with a combination of omega-3 fatty acids, carotenoids, and vitamin E. The number of errors mae at the earlier stages of the working memory task were comparable over time. However, as the cognitive load increased (i.e. the task became more difficult) individuals in the active group outperformed individuals in the placebo group, making 38% fewer errors than those receiving the placebo. 

We observed statistically significant increases in carotenoid and omega-3 fatty acid concentrations in blood, as well as statistically significant increases in tissue carotenoid concentrations among the active group in comparison to the placebo group. Importantly, individuals with a greater increase in each nutrient made fewer errors in the working memory task suggesting that the observed changes in nutrition levels were directly related to the observed improvements in working memory performance. 

What are the implications of your study?

These findings suggest that the working memory capacity of individuals in the active group was favourably altered over time and that these positive changes may be attributed to the enrichment of carotenoids and omega-fatty acids, given that the magnitude of change in cognition was related to the magnitude of change in nutrition levels. 

Working memory refers to the temporary holding of information for later access and application (e.g. holding a telephone number or address in your mind). In terms of practical benefits, an improved working memory can enhance our capacity to retain information and prioritise the steps needed to make decisions and solve problems. It can also help us to focus on the task at hand such as planning and prioritising tasks for the day ahead, or remembering key information such as keeping appointments. 

This research adds to the existing body of literature, which shows that nutrition can play a positive role in maintaining and improving our cognitive performance, which may in turn reduce the rate of cognitive decline and our risk of dementia in later life (Davinelli et al. 2021, Solfrizzi et al. 2018). 

Why did you choose CANTAB^TM?

CANTAB^TM is one of the most widely employed cognition batteries and it is sensitive in assessing cognitive performance for many population groups including healthy individuals and patients with neurodegenerative disorders.

What are the next steps?

The research that I have been involved in to date has demonstrated improvements in cognitive performance in both cognitively healthy older adults and individuals with mild cognitive impairment following supplementation with omega-3 fatty acids, carotenoids and vitamin E. Going forward, and as part of my Marie Skłodowska Curie Action fellowship, I aim to advance our understanding of the parts of the brain and neural networks that are strengthened by specific foods using state-of-the-art methodologies and technologies from the fields of nutritional epidemiology and cognitive neuroscience available at the University of Illinois Urbana-Champaign. With my colleagues in the US I also plan to examine the longer-term effects of dietary patterns on how our brains organise and communicate information, as well as potential differences between males and females in this regard.

Further Information

CARES was published with colleagues at the NRCI (Prof. John M. Nolan, Dr Alfonso Prado-Cabrero, Mr Warren Roche, Mr Tommy Power), St. James’s Hospital, Dublin (Dr Robert Coen), and University Hospital Waterford (Prof. Ríona Mulcahy). The research was funded by the Howard Foundation UK (UK Charity Registration Number 285822).

References

Davinelli, S., S. Ali, V. Solfrizzi, G. Scapagnini & G. Corbi (2021) Carotenoids and Cognitive Outcomes: A Meta-Analysis of Randomized Intervention Trials. Antioxidants (Basel), 10.

Lloret, A., D. Esteve, P. Monllor, A. Cervera-Ferri & A. Lloret (2019) The effectiveness of vitamin E treatment in Alzheimer’s disease. International Journal of Molecular Sciences, 20, E879.

Power, R., A. Prado-Cabrero, R. Mulcahy, A. Howard & J. M. Nolan (2019) The Role of Nutrition for the Aging Population: Implications for Cognition and Alzheimer’s Disease. Annu Rev Food Sci Technol, 10, 619-639.

Solfrizzi, V., P. Agosti, M. Lozupone, C. Custodero, A. Schilardi, V. Valiani, A. Santamato, R. Sardone, V. Dibello, L. Di Lena, R. Stallone, M. Ranieri, A. Bellomo, A. Greco, A. Daniele, D. Seripa, C. Sabbà, G. Logroscino & F. Panza (2018) Nutritional interventions and cognitive-related outcomes in patients with late-life cognitive disorders: A systematic review. Neurosci Biobehav Rev, 95, 480-498.