Do food and nutrition have therapeutic value for disorders of mood and conation?

INTRODUCTION

The use of psychotropic medication in psychiatric disorders has brought significant reduction in mental health morbidity and related mortality. However, over the years, we have realized that the benefit of these medication on mental health are overshadowed by many important side effects, necessity of medication for an uncomfortably long period, and inadequate compliance requiring significant adherence-oriented efforts.[1,2,3] Additionally, medication may be effective in a third of the population and end up in relapse, regardless, in significant half of the population.[4,5]

Off late, there has been growing interest toward lifestyle-related factors, which appears to be of both prophylactic and therapeutic value in mental well-being.[6] Research evidence for the role of physical exercise,[7] sleep,[8,9] mindfulness,[10,11] social connectedness,[12,13] environmental mastery,[14,15] and so on, have been adequate and growing. Among these factors, diet have attracted lot of attention by researchers off late.[16,17,18,19,20,21,22,23]

Growing body of researches indicates significant role of diet not only in promoting positive mental well-being, but also in treatment of mental illness. Few of the concluding theories that have churned out of researchers in this direction are as follows:

Neurotransmitter precursor

Most of the mental illnesses are due to neurotransmitter disturbances/deficits, which are synthesized primarily by amino acids. The amino acids provided by the diet addresses these deficits and imbalances, leading to desired therapeutic effect.[3,24,25]

Adult hippocampal neurogenesis

Some area of the brain have potential for neurogenesis lifelong, important few of them are in hippocampus and neocortex. These areas have active role in emotion and cognition and the defect in these often leading to mental illnesses. Considering that these areas are still capable of adult neurogenesis, an appropriate diet conducing of neurogenesis will improve our cognitive reserve and dispel any mental illness likely to arise.[26,27]

Gray matter constituents

Brain gray matter consists of 50% fatty acid, which is polyunsaturated. Of which, around 33% belong to the family of omega-3 fatty acid, which is found abundant in whole fish. The diet, thus, rich in omega-3 fatty acid is a conducive resource for neurogenerative process and mental well-being.[23,28]

Gut-brain axis

Diet have also been found to affect mental health though the gut-brain axis, the effect may be either direct through neural axis or indirect through inflammatory or hormonal changes in the gut and associated vascular system.[29] Many evidences have come in support of gut-brain axis involvement in mental health morbidity, few of which are important and as follows: -

1. Mediterranean diet, an unprocessed and fiber-rich diet, is anti-inflammatory in nature and protective against mental illnesses. Whereas, Western diet, a highly processed diet has pro-inflammatory action, resulting in many inflammatory illnesses, which is detrimental to cognition, hippocampal function, and blood–brain barrier. This hypothesis is further reinforced by efficacy of anti-inflammatory agents in symptom reduction in mental illness.[30,31,32,33,34,35,36,37,38]

2. Diet low in fiber and rich in refined sugar, artificial sweeteners, and saturated fats carbohydrate are more likely to trigger inflammatory process affecting the gut mucosal layer adversely and increased epithelial permeability. This may lead to spread of inflammatory agents through blood stream to distant areas including brain.[32,39,40]

3. Western diet by its being processed diet, are primarily acellular in nature. Thus, it gets digested and converted easily and early in the gut. This early conversion and in excess to the expected affects the microbial milieu adversely, leading to significant loss of bacteria vital for microbiome function and may induce heritability by epigenetic changes. Mediterranean diet, which is unprocessed plant and animal products, are cellular with intact cell walls or cell membrane. These traverse through intestinal lumen in the intended speed, gets digested across the span of digestive tract and reaches colon, rich in fiber. This diet appears to maintain balance and promote growth of fiber degrading bacteria in colon and generation of beneficial metabolites.[41,42,43,44,45,46,47]

4. Advanced glycation end products (heat-treated food preparation high in processed fat and carbohydrate, breakfast cereals, etc) promote growth of harmful microbes, reduce helpful microbes, and increases colonic permeability. These diets induced inflammation also causes food craving and hyperphagia, generating a vicious circle of bad diet and bad effects.[48,49,50,51,52,53]

DIET AND NUTRIENTS IN SPECIFIC MENTAL ILLNESSES

Role of diet and nutrients have been researched in few specific mental illnesses, commonly being depression, bipolar disorder, schizophrenia, and obsessive-compulsive disorder.[3]

Diet and depressive disorder

Available research in this direction suggests that diet has significant therapeutic effect and may be promising as supplement or adjunct with standard medication in future.

Omega-3 fatty acids,[54,55] vitamin Bs,[56] minerals,[57] and neurotransmitter precursor amino acids (tryptophan,[24,58] tyrosine,[59] phenylalanine,[3] methionine[60]) have been found to reduce incidence of mental illnesses as well as helpful in treatment of mood disorder and depression. High fish diet that is rich in omega-3 fatty acid is psycho-protective. It leads to production of prostaglandin, leukotriene, and other brain chemicals of antidepressant value. Its action through peroxisomal proliferator-activated receptors leading to inhibition of G protein, protein kinase C, and various ion channel receptors (Ca, Na and K) was also been proposed to reduce the depression.[3]

Serotonin precursor tryptophan restores serotonin and alleviates depression. Tyrosine and its precursor phenylalanine restore dopamine and noradrenaline, the substrate for alertness and arousal.[3] Methionine product S-adenosyl methionine promotes production of neurotransmitters in the brain.[60] Folate and vitamin supplements have been found to reduce depressive symptoms.[56] Magnesium salts (glycinate and taurinate) has shown quick recovery in many a depressed patient within a week's span.[57] Available research suggests that Mediterranean diet alone reduces the risk of depression by 30%.[61]

Bipolar disorders

Biochemical abnormalities seen in bipolar disorders, which can be corrected with diet are as follows[3,62,63,64,65]:

1. Oversensitivity to acetylcholine

2. Increased vanadium

3. Decreased vitamin B, taurine, omega-3 fatty acid, or vitamin C

4. Anemia

Vitamin C has protective effect on vanadium-induced brain damages. In association with natural supply of body lithium, it is found to reduce manic and depressive symptoms. Taurine made from cysteine in liver has soothing effect on brain and also block excess of acetylcholine effect. Other nutrients found to be effective are L-tryptophan and choline. Lithium orotate, a nonprescriptive, diet supplement, in contrary to pharmaceutical lithium, is required in much lesser dosage and crosses blood–brain barrier.[3]

Schizophrenia

High-dose glycine has shown to improve social withdrawal, affective flattening, and apathy.[3,65] Omega-3 fatty acid product, especially eicosapentaenoic acid, as an adjunct with medication, has shown to reduce symptoms of schizophrenia significantly.[66,67,68,69,70,71,72]

Obsessive compulsive disorder (OCD)

Tryptophan and tryptophan supplement has shown to increase serotonin level and improve obsessive-compulsive symptoms. St Johns wort as an adjunct with selective serotonin reuptake inhibitor has shown significant reduction in recurring thoughts and compulsive behavior.[3]

Recommended dosage of nutrients in psychiatric illnesses based on proposed deficiency is shown in Table 1.

Table 1.

Recommended dosage of nutrients in psychiatric illnesses based on proposed deficiency

Name	Dosage
Depressive disorder
Omega-3 fatty acid	Upto 9.6 gm/day[28]
Folate	0.8 mg/day[56]
Vit B12	0.4 mg/day[56]
Magnesium salt	125-300 mg each meal and at bed time[57]
Bipolar disorder
Omega-3 fatty acid	1-2 gm/day[62,63,64,65]
Vit C	3 gm single dose[3]
Lithium orotate	150 mg/day 4-5 times a week[3]
Schizophrenia
Glycine	60 gm/day[65]
vegEPA capsule	Contains 280 mg of EPA from marine omega-3 fish oil, 100 mg of organic virgin evening primrose omega-6 oil, and 1 mg of vit E. Outer capsule made out of fish gelatine[66,67,68,69,70,71,72]
OCD
St Johns wort	900 mg daily in adjunct with fluoxetine/paroxetine[3]

Vit=vitamin, EPA=eicosapentaenoic acid, OCD=obsessive-compulsive disorder

DIETARY SCORING

A study by LaChance and Ramsay ranked antidepressant foods by calculating antidepressant food score based on their antidepressant nutrient density. Nutrient rich in antidepressant value were vitamins (vitamins A, B1, B6, B12, C, and folate), minerals (potassium, magnesium, iron, zinc, and selenium), and long-chain omega-3 fatty acids. Antidepressant food scoring of various food items is shown in Table 2.[73]

Table 2.

Antidepressant food scoring of various food items

Antidepressant food	Antidepressant food score range
Watercress	127%
Spinach	97%
Lettuce	74%-99%
Mustard, beet greens & turnip	76%-93%
Swiss chard	90%
Fresh herb	73%-75%
Chicory greens	74%
Pummelo	69%
Oyster	56%
Liver and organ meats	18-38%
Poultry giblets	31%
Mussels	28%
Crab	24%
Goat	23%
Fish roe, bluefish, wolfish	19%

CONCLUSION

Available evidence supports that Mediterranean diet, unprocessed food, omega-3 fatty acids, nutrients rich in essential amino acids, and vitamins have therapeutical potential in many mental illness. It has been used as supplement as well as adjunct with favorable outcome. However, whether it will be good substitute or adjunct for psychotropic medication, it will be evident with further research and empirical evidences over time. The very fact, of its utility, with prudent use, brings optimism amidst the afore-mentioned concerns and complications of psycho-pharmacy.