Table 3.

Possible interaction between genes and diet in major psychological disorders

Serial No.	Psychological condition	Major genes involved	Foods/nutrients affecting the gene1)	Existing research (if any)2)
1	Depression	(SLC6A4/5HTT), (5-HTTLPR), (HTR2A) (Su et al., 2009; Lam et al., 2018) https://genesight.com/articles/get-to-know-a-gene-htr2a/ BDNF (Yang et al., 2020)	TRP and serotonin TRP (L-tryptophan) supplements are believed to decrease depressive symptoms. Food rich in serotonin and tryptophan: salmon, nuts and seeds, nuts and seeds, turkey and poultry, and pineapple Green tea, dark chocolate, soy, blueberries, and fatty fish	Yes (Gibson, 2018) Yes (however, foods relating to BDNF haven’t been efficiently researched yet)
2	Bipolar disorder	Ankyrin 3 (Hughes et al., 2018) Dopamine D4 receptor (Gafarov et al., 2020) Monoamine oxidase A (Lim et al., 1995; Golub and Hogrefe, 2014)	Lithium − Iron	No
3	Schizophrenia and other psychotic disorders	AKT1 (Thiselton et al., 2008; MedlinePlus, 2017a)	High fat and high sucrose, polyunsaturated fatty acids, and high phosphate	No
4	Dementia	Apolipoprotein E, amyloid beta precursor protein (ZFIN at https://zfin.org/ZDB-GENE-010724-18) (de Chaves and Narayanaswami, 2008)	Vegetable oil, estrogen, sesamol, and docosahexaenoic acid	No
5	PTSD	FK506 binding protein 5 (ZFIN at https://zfin.org/ZDB-GENE-030616-630) COMT (ZFIN at https://zfin.org/ZDB-GENE-050913-117) (Winkler et al., 2017)	Quercetin, (milk) lactoperoxidase, fish oil, high fat and high sugar diet, fructose, maize, vitamin D, Medicago sativa fiber, and seed oil of Brassica napus	No No
6	Eating disorders	FTO (Müller et al., 2012) 5-HTTLPR (Gorwood, 2004; Calati et al., 2011) Met allele of the functional BDNF rs6265 (Val66Met) Lower level of BDNF increases anxious and worrisome behaviors (Ribasés et al., 2005; Dmitrzak-Weglarz et al., 2007)	Carbohydrates and macronutrients Low protein diet, acute tryptophan protein, fat diet, and blueberries High fat and high carbohydrates decrease hippocampal BDNF level	No No No
7	Autism spectrum disorder	SHANK3 (Durand et al., 2007) Neuroligin 3 and 4 (Jamain et al., 2003)	Proline rich foods: broccoli, bell peppers, gelatins, soy protein concentrate, and zinc supplements Requires further research	No No
8	OCD	COMT (Pooley et al., 2007)	As mentioned above	No
9	Phobias	Requires further research	−	−
10	Substance use	Alcohol dehydrogenase 1B (Class I) (Arg48) (Macgregor et al., 2009) Dopamine receptor D2 (Thanos et al., 2001; Mishra et al., 2018)	Requires further research TAGs and protein rich food	No No
11	Personality disorders	CACNA1C (Smedler et al., 2019)	Requires further research	No

¹⁾The major genes associated with numerous psychological disorders are listed in column 2. In column 4, the nutrients that have an effect on these genes are listed, creating an indirect relationship between the nutrients and the psychological condition. This facilitates the development of nutrigenomics with regard to psychological disorders.

²⁾The existing research column signifies that there is negligible research linking nutrigenomics to mental illnesses. If the nutrients affecting the genes involved in psychological disorders are targeted in the patients, it might transpire as a prodigious treatment strategy.

SLC6A4, a member of the solute carrier family 6; 5-HTT, serotonin transporter protein; 5-HTTLPR, serotonin-transporter-linked promoter region; HTR2A, 5-hydroxytryptamine receptor 2A; TRP, tryptophan; BDNF, brain-derived neurotrophic factor; AKT1, a serine/threonine protein kinase; ZFIN, Zebrafish Information Network; COMT, catechol-O-methyltransferase; FTO, fat mass and obesity-associated/alpha-ketoglutarate-dependent dioxygenase; SHANK3, SH3 and multiple ankyrin repeat domains 3; CACNA1C, calcium voltage-gated channel subunit alpha1 C.