We often discuss how eating a healthy diet is good for our physical health – less often talked about is how eating a varied and nutritious diet is also important for the health of our brains. Having gone many years not knowing this myself, I’ve now become passionate about sharing this message as widely as I can. I think food is unique in that it has the potential to either support or hinder our brains. At its simplest, we all need to eat – but this provides us with the opportunity to support our brain health many times over through our food choices.
For my PhD research, I’m exploring how different dietary patterns relate to brain health — what aspects of our diet help and what impair brain functioning.
The MIND diet is a dietary pattern that was created specifically to optimise brain health by a team of researchers in America. I am investigating whether following this diet is associated with better performance in cognitive tasks and a reduced risk of developing dementia. The MIND diet plan was created by exploring the evidence for foods strongly related to positive cognitive outcomes. Broadly speaking, it is a Mediterranean-style diet, which includes lots of different plant foods such as vegetables (particularly green leafy vegetables), wholegrains, berries, nuts, and beans. The diet also advocates eating oily fish and chicken weekly and using olive oil. In addition, the MIND diet suggests limiting our intake of foods such as cheese, red meat, desserts, and fried food. At present, there is limited understanding of whether non-mediterranean populations (such as those of us in the UK) cognitively benefit from eating these foods.
Using large population studies which have collected information on what the participants eat, I score how well people adhere to the MIND dietary pattern and then see whether this is associated with later cognitive performance. So far, I have found an association between eating these foods and better cognitive performance 12 years later. Further, for people with risk factors for cardiovascular disorders (e.g. high cholesterol and blood pressure, smokers, high BMI), eating the MIND diet was associated with better cognitive performance 23 years later. These findings suggest there may be long-term cognitive benefits for everyone following the MIND diet, with longer-lasting cognitive benefits for people with greater health vulnerabilities.
Another diet aspect I focus on is the consumption of Ultra-Processed Foods (UPFs). These foods are a hot topic at the moment, with plenty of discussion about their possible association with a variety of health conditions. UPFs are generally defined as products created through industrial processes which contain ingredients that aren’t used in our own home cooking, such as stabilisers, emulsifiers, and preservatives. These products often contain a long list of ingredients and are typically high in fat, sugar, and salt. Many of these foods have been specifically created to be highly appealing and palatable — inevitably, they are commonly overconsumed. Multiple studies highlight how greater consumption of UPFs is associated with an increased risk of negative health outcomes (e.g. cardiovascular disorders, obesity, and diabetes). However, relatively little research has looked into links between UPF consumption and brain health.
Again, using large-scale population studies, I have investigated whether eating more of these UFPs is associated with a greater risk of dementia risk or lower cognitive performance. Analysis so far has shown that eating UPFs is indeed associated with an increased risk of developing dementia.
With the research only partly completed, the next stage is to replicate this analysis in other cohorts and further explore whether these foods are associated with cognitive performance. Additionally, my future investigations will explore whether eating UPFs is associated not just with cognitive performance but also with the rate of cognitive change in older age.