A number of mechanisms that have been implicated in depression and anxiety , such as gut dysbiosis , impaired neurogenesis , and monoaminergic dysfunction , may be triggered by a neuroinflammatory process . 48 Studies have shown that higher levels of interleukin-6 and C-reactive protein have led to the development of depressive symptoms . 5 In addition , depression , as an independent factor , has been found to cause higher levels of inflammatory cytokines . 5 Proinflammatory cytokines form the core of neuroinflammation in depression and are capable of disrupting the brain ’ s regulatory and signalling mechanisms involving behavioural and emotional aspects . 47 Additionally , cytokines induce depressive and anxiety symptoms by altering the activity of neurotransmitters . 5 Stress can lead to a larger inflammatory response , which has also been linked to anxiety and depression . 5
The gut microbiome has an important role in the human body . 44 Microbiota are microorganisms that live in the digestive tract of humans . 5 The brain and gut work in a bi-directional manner , 44 with the potential to affect each other ’ s functions and significantly affect stress , anxiety , depression , and cognition . 44 Research shows that healthy gut microflora transmit brain signals through the pathways involved in neurogenesis , neural transmission , microglial activation , and behavioural control under stable or stressful conditions . 44 Further , research supports the importance of the relationship between gut microbiota and mental health . 5 Chronic stress exposure has consequential effects on the gut microbial composition and HPAaxis . 47 Stress can harm the microbiome of the intestines through activation of the sympathetic nervous system and slowing of the digestive process . 49 Stress can also lead to changes in the structure and function of the intestinal barrier , 45 , 49 leading to inflammatory and oxidative stress states . 45 Psychological stress can weaken one or multiple pathways of the gut-brain axis causing a dysfunction in the axis leading to the risk of depression . 50 Compromised intestinal permeability has been frequently associated with depression . 47 Compromised and increased intestinal permeability could be involved with the vicious circle of the interaction between the gut microbiota , central nervous system , and the periphery in the activation of inflammatory responses ( this is sometimes referred to the “ leaky-gut hypothesis ”). 47 Studies have shown that depression and anxiety can increase , or cause alterations in , the permeability of the gut barrier , resulting in bacteria seeping into the circulation and producing an inflammatory response through an immune response and endotoxin translocation . 5
It is worth noting that although depression and anxiety are different disorders , their symptoms frequently overlap in individuals , making them difficult to diagnose and treat adequately . 48
Management of depression
Optimal management of a person with depression is holistic in nature . It can be likened to piecing together the complex puzzle that is mental health and wellbeing . The focus is on treating the whole person ( mind , body , spirit ). 16 Identifying and treating the underlying causes , background activity , and triggers 16 are very important in the management of depression . This article focuses on the importance of nutritional and lifestyle medicine via various mechanisms of action in the management of depression .
It is important for people living with depression to get professional help . 51 Health professionals play an important role in the holistic care of a person suffering from depression , particularly because depression and other mental health conditions can affect a person ’ s decision-making processes . This may impair their ability to get information on their health and on potential management and prevention , and may have a detrimental effect on their physical health . 4
Nutritional medicine
Optimum nutrition is the foundation for optimum health . 16 , 52 In this section , the role of diets ( such as the Mediterranean diet ), vitamins ( such as B vitamins and Vitamin D ), minerals ( such as magnesium and zinc ), omega-3 , probiotics , and water in the management of mental health and wellbeing will be discussed .
Diets The relationship between diet and mental health is complex . 53 A traditional whole-food diet provides an abundance of micronutrients , polyphenols , and healthy fats that are individually and collectively associated via multiple pathways with optimal brain function . 8 The Mediterranean diet is characterised by abundant fruit , vegetables , cereals , beans , nuts , seeds and fish , and has numerous health benefits , including in managing depression , and promoting cardiovascular health ,
52 , 54
and cardiometabolic health . Observational studies have found that a high adherence to traditional dietary habits , such as the Mediterranean diet , has been associated with reduced probability and / or risk of depression . 8 A parallel-group , open-label , randomised controlled trial found that a Mediterranean diet improved quality of life in young males ( 18 – 25 years ) with moderate to severe depression . 21 The glycaemic index diet has numerous health benefits , including reducing
52 , 54 inflammation and oxidative stress .
B Vitamins The B vitamins perform essential , closely interrelated roles in cellular functioning , and act as coenzymes in a vast collection of catabolic and anabolic enzymatic reactions , 55 energy metabolism , cell signalling , and nervous system function . 56 , 57 The synthesis of neurotransmitters involves vitamin B1 ( thiamine ), B6 ( pyridoxine ), and B12 ( cobalamin ). 55 As vital precursors to neurotransmitters , it is suggested that these key vitamins optimise function of the peripheral and central nervous systems , having neuroprotective effects on
190 | vol29 | no4 | JATMS