Ketogenic Diet, Mediterranean Diet, and Mental Health

The role of nutrition and eating patterns in the maintenance of health and development of mental disorders has become a major focus of research over the past several decades. While key developments in pharmacotherapy and the increasing availability of evidence-based psychosocial treatments have significantly improved the survival and quality of life of those with neurological and psychiatric conditions, substantial room for improvement remains, with many individuals seeking more integrated and self-directed approaches to healing. This chapter explores the potential benefits of nutritional intervention for treating various neuropsychiatric symptoms and mental disorders by examining two well-studied dietary regimens together with their putative mechanisms for impacting emotional and cognitive health and functioning. Ketogenic diets, which typically limit carbohydrate consumption to less than 50 g daily, stimulate nutritional ketosis, which leads to adaptive changes in cellular energy utilization within the CNS; such alterations are thought to have neuroprotective and anti-inflammatory effects that have been found useful in ameliorating the derangements in glucose metabolism, oxidative stress, mitochondrial dysfunction, dysregulated neurotransmission, and pathologic alterations in the gut microbiome that accompany conditions like substance-related and addictive disorders, major depression, and anxiety states. Evidence suggests that a Mediterranean diet, which is marked by increased consumption of fruits, vegetables, legumes, extra virgin olive oil as a key energy source, multiple weekly servings of fish, wholegrain cereals, and fermented dairy products, together with sparing consumption of red and processed meats and avoidance of sugar-sweetened and highly-processed foods, is effective in improving metabolic and neurocognitive parameters with resulting reduced incidence of depression, improvement in sleep quality and duration, and reduction in the rate of neurological decline and development of neurodegenerative conditions such as major neurocognitive disorders due to Alzheimer’s and Parkinson’s disease. If additional well-designed studies in clinical populations continue to support the therapeutic benefits already demonstrated for ketogenic, Mediterranean-style, and other evidence-based healthy eating regimens, these dietary interventions have great potential not only as safer and less expensive treatment approaches but also as preventive strategies for a range of prominent medical conditions.