AMBROSIAC

The aged brain is particularly vulnerable to stress-induced cognitive decline and will benefit tremendously from mechanistically-oriented dietary interventions to attenuate such cognitive impairment and to provide a general boost to brain health. Moreover, cognitive decline is increasingly present in the ageing population, who are living with chronic diseases and subjected to elevated levels of psychological stress, which are both huge challenges for the EU economy and society.

AMBROSIAC (A Menu for Brain Responses Opposing Stress-Induced Alterations in Cognition) investigates the influence of nutrition on stress-induced cognitive deficits in memory and executive functioning from adulthood to old age; and the impact of a nutritional intervention on cognitive ability, stress vulnerability and stress perception. It further interrogates the molecular mechanisms by which targeted nutritional interventions can improve stress-induced vulnerabilities in cognition in preclinical models.

Within the AMBROSIAC project we have determined that individuals on a non-obesogenic diet had lower levels of systemic inflammatory markers, and performed better in cognitive performance assessments following exposure to an acute stressor. Furthermore, supplementation of normal diet with vitamin A and an Ω-3 fatty acid-rich supplement docosahexanoic acid (DHA) improves working memory in aged individuals with elevated levels of the stress marker cortisol. Interrogating these phenomena using in vitro and preclinical modalities, we determined that short-chain fatty acids, Ω-3 fatty acid-rich and DHA-rich supplementation have anti-inflammatory properties; and can reverse stress-induced deficits in behaviour and cognitive performance. These beneficial effects were not observed in an animal model that was genetically bred to lack the ability to produce histamine. The beneficial effects of these dietary supplements on cognitive behaviour, stress and weight suppression were associated with changes in specific genera of bacteria within the gut. Further evidence for a role of gut bacteria in healthy ageing, stress and cognitive performance is provided by findings that prebiotics (dietary fibres) reduced neuroinflammation in ageing animals, and that a transfer of microbes belonging to young animals into aged animals reduced inflammatory markers in ageing animals.

These findings may impact on nutritional information for specific diets as a modulator of the microbiome to act as a prophylactic in improving healthy ageing (reducing stress, and maintaining cognitive performance), specifically in elderly individuals with elevated cortisol levels. Ultimately, these data may help to significantly transform healthcare strategies and policies, and lead to innovative, evidence-based approaches from the food industry which will notably improve dietary habits among consumers.