At Vitafoods Europe I will present data, published and unpublished, from my own and others, which demonstrates the capacity for specific food components to impact on mental performance acutely. The presentation will cover some effects of breakfasts varying in glycaemic response on memory performance in children and young adults as well as long-term effects of improving glycaemic control in the elderly.
The methodological differences between studies that do and do not demonstrate effects of nutritional manipulations on mental performance are critical to understanding functional foods for mental performance and the claims which can be made for them.
Critical scientific scrutiny
There is a huge commercial and public interest in the capacity for foods to influence our psychological state, wellbeing and cognitive function. Some interventions have been suggested by research and leapt upon by the popular press and taken up eagerly by consumers. The evidence for some of the recommendations is at best suggestive and demands critical scientific scrutiny.
Examination of claims by EFSA is in progress and the majority of the Article 13 and 14 claims released to date have been negative. This could be for a number of reasons, for example, food under scrutiny is not well characterised, that the evidence does not convincingly support the proposed claim or there is insufficient evidence to demonstrate a cause and effect relationship. Demonstrating causal effects in the realm of food intake is difficult and there may be important factors which influence whether or not an ingested nutrient has an effect on mental performance.
In order to evaluate the evidence for the effects of foods, food components and dietary habits on cognitive function, it is important to understand what we mean by “cognitive function” and how we might measure it in response to nutritional interventions. Cognitive function or “mental performance” is a broad overarching term and there is no single test or measure that captures cognitive function. Hence studies, and claims, need to be focused and we need to identify cognitive domains that are specific and measurable in an accurate and valid manner.
Consumption of certain macronutrients is thought to lead to metabolic and biochemical changes that may influence subsequent brain function, including cognitive function and appetitive response. Cognitive function is strongly protected and enhancement of performance is unlikely in healthy adults. Nutritional manipulations which exert different metabolic effects sometimes exert no significant influence on mood, appetite, or cognitive performance.
Some groups, such as children, diabetics and the elderly, may be more vulnerable to nutritional manipulations than young healthy adults on whom much research is based. The magnitude of metabolic changes that are required to induce an effect on cognitive performance may be related to glycaemic response or the glycaemic index of the food consumed. The potential for functional foods for prevention and enhancement of cognitive function in the long term and the impact of our habitual diet on our current and future cognitive function are also important.
The importance of establishing the mechanism of action of observed effects and the gaps in our current evidence base will also be considered. All of these purported effects of food components on cognitive function will be examined in the light of the new standards that are being applied to claims throughout Europe by EFSA. To this end I will also consider some of the specific guidelines for such claims (Article 13 and Article 14) and the reasons for rejection for some claims to date.
Professor Dye will deliver her presentation on ‘Diet and Cognitive Function’ on Wednesday 11 May at 11.55am. To find out more about the Vitafoods Europe Conference click here.