Adana et al (2019) predict that Europe in the coming decades will see a rise in the burden of psychiatric disorders, mood disorders and stress-induced cognitive vulnerabilities, and they highlight the importance of continuing research on the role of diet in mental health. This is because of mounting evidence that the relationship between diet and mood extends beyond heaving a contented sigh after a nice meal. For instance, DiNicolantonio et al (2017) report that ‘sugar meets many of the criteria for a substance of abuse and could be potentially addictive in humans’, while Marx et al (2017) state that ‘recent systematic reviews examining the association between diet and common mental disorders have shown healthy dietary patterns to be inversely associated with the probability of, or risk for, depression’.
Marx et al (2017) consider that the potential biological processes involved in the diet and mental health relationship primarily implicate inflammation, oxidative stress, and neuroplasticity, ‘with the gut microbiome as a key mediating pathway for each of these processes.’ This theme is expanded on by Mörkla et al (2020) who note the importance of the gut-brain axis, a bidirectional communication pathway between the intestine and brain, connecting the enteric nervous system to the central nervous system. For example, Mörkla et al (2020) cite evidence showing a reduction in the number of bacterial species in a range of mental disorders, as well as obesity, observing that intestinal bacteria intervene directly in our neurotransmitter metabolism, especially the serotonin metabolism, which is significant from a psychiatric perspective. And after a 12-week, randomised controlled trial of a modified Mediterranean diet model in the treatment of moderate to severe depression, Jacka et al (2017) concluded that ‘dietary improvement may provide an efficacious and accessible treatment strategy for the management of this highly prevalent mental disorder, the benefits of which could extend to the management of common co-morbidities.’
Massachusetts-based psychiatrist 3Dr Georgia Ede (2021) has helped pioneer nutritional psychiatry in her psychiatric practice, and told JPrP that in her four years of residency training, food wasn't mentioned once: ‘For decades, our treatment paradigm has been the trial- and-error use of psychiatric medications intended to address neurotransmitter imbalances, without seeking to understand what might cause these imbalances in the first place.’
Although recommending different therapeutic diets in her practice, Dr Ede considers the ketogenic diet as a particularly important tool: reliably normalising blood glucose; lowering blood insulin concentrations; reducing inflammation and oxidative stress; supporting the brain's growth and repair pathways; helping to correct neurotransmitter imbalances; and improving the brain's access to energy: ‘One of the benefits,’ explains Ede, ‘of a strategy that fundamentally improves brain metabolism and whole brain health rather than a medication that targets specific neurotransmitters, is that it can be useful for a variety of diagnoses,’ although she is careful to point out that ketogenic diets are not right for everyone, and their use in managing psychiatric disorders often requires specialised knowledge and expertise, particularly when medications are involved. Yet, it is interesting to note the findings of Phillips et al (2021) who undertook the first randomized trial to investigate the impact of a ketogenic diet in patients with diagnoses of Alzheimer's disease (AD). They found that high rates of retention, adherence, and safety appeared achievable using a 12-week modified ketogenic diet with AD patients, and that compared with a typical diet supplemented with low-fat healthy-eating guidelines, ‘patients on the ketogenic diet improved in daily function and quality of life, two factors of great importance to people living with dementia’ (Phillips et al, 2021).
Dr Ede believes a ketogenic diet can reliably normalise blood glucose and lower blood insulin concentrations. This reduces inflammation and oxidative stress; supporting the brain's growth and repair pathways
How does Dr Ede envisage a dietary role in psychiatric practice developing in the future? ‘Everyone with a mental health concern deserves a metabolic evaluation to look for potentially reversible root causes of their symptoms and should be offered counseling about the importance of dietary quality to their mental health.’ Dr Ede also detects growing public interest in these new treatment options, ‘and when people discover and apply them, they share their success with others, including their clinicians. Most people have been feeding their brains improperly their entire lives and have no idea how much better they could feel if they had the information, tools, and support to begin making healthy changes.’