Introduction: While it is widely known and accepted thatproper nutrition is vital to physical health throughout the lifecycle 1, 2, the relationship between nutrition andneurocognition and mental health has been counterintuitively less acknowledged 3. However, increasing evidence indicates that both nutritional deficiencies and excesses have deleteriouseffects on brain development and functionality, potentially resulting inimpaired neurocognition or psychiatric disorders 3 4. Other emerging evidence suggests that conversely, adequate nutritionpromotes optimal brain development, neurocognition, and mental health by preventing,mitigating, and/or reversing negative effects 5.One of the earliest studies identifyinglinks between nutrition and neurocognition and mental health was in 1915 by psychiatrist,H. Douglas SingerFI1 , who found that adults with Pellegra, a disease from niacin (Vitamin B-3)deficiency causing dermatitis and diarrhea, FI2 also experienced dementia and negative changes inmental health, including anxiety and depression 6. A landmark study based on datafrom the Dutch Winter Famine of 1944-1945, examined a cohort of offspring bornto mothers exposed to starvation (400-800 calories per day) during World War II,and found that these offspring had atwo-fold increased risk of developing schizophreniaFI3 compared to controls 7. Utilizingthe same birth cohort, later research found that these offspring also experiencedimpaired cognitive function in mid to late adulthood 8.
Although the degree of vitamin deficiencyand malnutrition were extreme in these studies, they elicited important cluesabout the crucial role of nutrition in neurodevelopment and long-termneurocognition and mental health prompting subsequent research. The exactphysiological mechanisms of these nutritional effects are still not yet fullyelucidated, but recent evidence suggests that theyare mediated through multiple interrelated biological processes and pathwaysincluding inflammationprocesses, the immune system, oxidative stress, the gut microbiome,neuroplasticity, and epigenetics FI4 9,10 11-15. Given the increasingevidence supporting the intricate relationship between nutrition and neurocognitionand mental health, it is essential to expand our understanding and awareness ofthese important links. Moreover, neurocognitiveand neuropsychiatric disorders, often intergenerational and perpetual, are anenormous emotional and economic burden to individuals, families, andsociety. According to the World HealthOrganization (WHO), neuropsychiatric disorders are the leading cause of globaldisability and projected to grow exponentially, potentially becoming aworldwide epidemic 16 17. While pharmacotherapy and psychotherapy remain predominate treatmentmodalities for neuropsychiatric disorders, they are not always effective andcan be cost-prohibitive.
Pharmacotherapy may also lead to undesirable sideeffects, which, in addition to expense, may interfere with compliance and therefore,proper treatment. Cognitive impairmentand dementia are also increasing worldwide and predicted to increasesignificantly more in developing regions 8 18 19, 20. Currently, no medications have been shown to effectively preventtheir progression or conversion to Alzheimer’s disease. Therefore, it is urgentto further investigate and consider nutritional factors as alternative preventativeand therapeutic opportunities, for both current and future generations. This paper will comprehensively review,analyze, and summarize the current evidence on various aspects of nutritionincluding micronutrients(vitamins and minerals), macronutrientsFI5 (carbohydrates, protein, fat) and overalldiet and their effects on neurocognition and mental health throughout thelifespan. Detailed explanations of theinvolved biological processes and metabolism of nutrients are beyond the scopeof this chapter; however, they will be briefly mentioned when necessary.Implications of the existing evidence, recommendations for advancing futureresearch, and public health policy matters will also be discussed. FI1Whatkind of professional? FI2Mostpeople wont’ know what Pellegra is, so clarify.
FI3Thanwho? FI4Presumablyyou will go through all of these later. FI5Thishas not been defined yet, so this may be worth doing here first.