The intricate relationship between food and the body has been extensively researched in previous decades. Food is everywhere. Diet regimes are everywhere. We are forever being told which foods we should and should not eat, leading to the consequential pang of guilt when you reach for the third digestive biscuit to dunk in your tea. Instagram now has the capability to provide you with a 365 day meal plan, in addition to a constant stream of aesthetically pleasing ‘health’ food and celebrities trying to fob you off with a supplement pill that will make you lose ten billion stone in a day.
At this time, it is therefore of great importance that emphasis is placed on the quality of research involving nutrition. Following the advice from research that has not been executed in a valid, replicable way can be quite dangerous. I personally have encountered numerous studies that claim to have found the wonder food that will cure cancer, yet upon reading further than the abstract I discover that the sample size is dramatically small. This. Is. Not. Good. Research.
How is neuroscience relevant to this you may ask? As a novel, ever advancing field of scientific research, neuroscience brings to the table highly advanced, reliable experimental techniques that can be adopted in nutrition research. I give you ‘Nutritional Cognitive Neuroscience’. This is a field of neuroscience that I have developed a personal passion for, and thus would like to share some of the most interesting studies that I have read about so far.
The Northern Manhattan Study
The development of magnetic resonance imaging (MRI) scans has revolutionised the world of brain research. It is now possible to create a detailed picture of the brain using magnetic field and radio waves that are of higher quality than other scanning techniques. A comprehensive study took place in 2012 that utilized MRI techniques to investigate the association between a Mediterranean-style diet (MeDi) and brain white matter hypersensitivities (WMH) in Northern Manhattan individuals (Gardener et al., 2012). WHM are markers of small vessel damage, and can be indicative of vascular risks such as stroke and the development of dementia. The MeDi diet, representing the dietary habits of the populations bordering the Mediterranean Sea, consists of a relatively high intake of fruit, vegetables, monounsaturated fat, fish, wholegrains, legumes and nuts, moderate alcohol consumption, and a low intake of red meat, saturated fat, and refined grains. The MeDi diet has long been referred to as a diet that ‘feeds the brain’.
The study adopted a large sample size of 1091 participants. The inclusions criteria for the study highlighted that the subjects had to have never received a stroke diagnosis and were required to be over 40 years of age. Individuals meeting these criteria were identified, and were provided a questionnaire that, upon completion, produced a MeDi score depending on the number of MeDi foods included in the diet. A total of 996 individuals completed both the questionnaire and had an MRI scan in a subsequent period ranging from 2 to 14 years later. The results of the study suggested that there was a lower burden of WMH, thus suggesting a lower risk of developing stroke and dementia, in individuals that consumed a largely Mediterranean diet (and therefore had a high MeDi score).
As with most research, there are limitations to the study. The sample can be considered to lack representation of the wider population (65% of the participants were Hispanic, 16% were white, and 17% were black) and in the time period between conducting the questionnaire, the participants could have adjusted their diets. Nonetheless, the study evidences the potential uses of modern neuroscience technology to investigate the relationship between food and the brain. In addition, the comprehensive study structure permits replication on a much larger, potentially world wide scale.
Lighting the Way – Understanding Nutritional Brain Circuits
Several of our articles have featured optogenetics, an exciting, novel technique to look at the relationship between genes and aspects of how the brain performs. Briefly, optogenetics involves using light to activate or turn off specific genes – literally at the flick of a switch. Several studies have utilised animal models to investigate how certain genes are involved in our relationship with food. Agouti-related protein (AGRP) is a neuropeptide that is produced by AGRP neurons in the hypothalamus. Using optogenetics, researchers have shown that activation of these neurons in mice is sufficient for the mice to rapidly increase their food intake. The extent of the eating is dependent on how many of these neurons are in their excitable state (Aponte et al., 2011). If these neurons are permanently activated, there is reduced energy expenditure and consequential weight gain in addition to increased fat storage. How does this translate to humans I hear you ask? Whilst mice are obviously animals and there are limitations to their use, they share many common genes with the human species. Therefore, it could be suggested from this research that obese individuals potentially have chronic activation of the AGPR neurons, and this may contribute to rapid weight gain that is extremely difficult to lose. It provides a possible genetic explanation for obese tendencies in certain populations. The power of such knowledge is phenomenal. Looking at the role of genetics in appetite and our body size opens many avenues for research that would not be possible without the utilisation of mice models.
Nutritional neuroscience is an emerging field that will no doubt reshape the health research landscape. Utilising cutting-edge techniques, nutritional cognitive neuroscience offers the potential to further our understanding of how food can nurture the brain, the potential implications of a poor diet on the health of our brains, and even how the genetic make-up of our brain can influence our relationship with food.
Author: Molly Campbell
Gardener, H., Scarmeas, N., Gu, Y., Boden-Albala, B., Elkind, M. S. V., Sacco, R. L., … Wright, C. B. (2012). A Mediterranean-Style Diet and White Matter Hyperintensity Volume: the Northern Manhattan Study. Archives of Neurology, 69(2), pp. 251–256. http://doi.org/10.1001/archneurol.2011.548
Aponte,Y., Atasoy, D., and Sternson, SM. (2011). AGRP neurons are sufficient to orchestrate feeding behaviour rapidly and without training. Nature Neuroscience. 14(3), pp. 351-355.