Introduction
Nowadays, both obesity and vitamin D deficiency are considered as epidemiological problems worldwide [1]. Obesity associated with common mental disorders such as depression, anxiety and low self-esteem have severe negative effects on people’s health and quality of life [4]. In addition, studies have found that patients with vitamin D deficiency suffer from mood disorders [10]. Physical activity is an effective method to improve the quality of life and emotional health, which can reduce diseases associated with obesity, such as depression and anxiety [15]. Pilates exercise is widely used to as an adjuvant treatment in various diseases [19]. This exercise, by focusing mostly on the core muscles, can reduce body weight [20]. The present study aims to investigate the effect of Pilates and vitamin D supplementation on the quality of life and mental health of overweight men.
Materials and Methods
This is single-blind clinical trial. Fifty overweight men were selected by a convenience sampling method and randomly divided into four groups of control, exercise, supplementation, and exercise+supplementation. The exercise and combined groups performed 8 weeks of Pilates, 3 sessions per week, one set of 2 repetitions, every two weeks, at an intensity of 50-75% of heart rate reserve, with a gradual increase of 5%. The supplementation and combined groups received 50,000 IU vitamin D capsule once per week. Assessment tools were the 36-item Short Form survey (SF-36) and the general health questionnaire (GHQ). The serum levels of 25-hydroxy vitamin D were determined using the ELISA method. The data were analyzed by paired t-test, one-way ANOVA, and Kruskal-Wallis test. P˂0.05 was statistically significant.
Results
The anthropometric characteristics of the subjects and their baseline vitamin D level presented in Table 1 were not significantly different between the groups. 

Based on the results in Table 1, the baseline vitamin D level in all groups were lower than normal level. The results showed that 8 weeks of vitamin D supplementation alone, Pilates exercise alone, and their combination led to a significant increase in the SF-36 and its two mental and physical health summary measures (Table 2), in the GHQ and its dimensions of somatic symptoms, anxiety and insomnia, social dysfunction, depression, as well as body weight loss.


The amount of changes in the mean scores of quality of life, mental health, and their dimensions were higher in the experimental groups compared to the control group. The effect of combining Pilates and vitamin D consumption on improving mental health, quality of life and their dimensions was higher compared to when they were used alone. There was no significant difference between the two Pilates and vitamin D consumption groups in terms of the study variables (P>0.05).
Discussion
The findings of the present study showed a significant increase in the overall SF-36 score and its mental and physical health measures in overweight men with lower vitamin D level. Moreover, an increase in total GHQ score was observed along with a decrease in its dimensions of somatic symptoms, anxiety and insomnia, social dysfunction and depression. Vitamin D may play a potential role in maintaining the balance of intracellular and extracellular calcium and the balance of excitatory (glutamate) and inhibitory (gamma-aminobutyric acid) neurotransmitters by the intracellular regulation of calcium storage and cellular signaling, and delay the onset of depression [33]. Vitamin D has a positive relationship with serotonin production; low levels of serotonin can cause depression [34]. The active form of vitamin D plays an important role in the regulation of tyrosine hydroxylase, which regulates the production of mood-regulating neurotransmitters (norepinephrine and dopamine) [35]. From a biological point of view, low levels of noradrenaline are effective in mood disorders, and exercise may exert an anti-depressant effect through the production of noradrenaline [39]. Exercise activates the Mammalian target of rapamycin as a serine/threonine protein kinase in brain areas that is involved in cognition and emotional behaviors, and can help improve mental health by reducing the effects of stress, anxiety and depression [40]. In addition, exercise increases the activity of serotonergic and adrenergic brain systems [41]. In the present study, no significant difference was observed between the effects of Pilates exercise and vitamin D supplementation on the SF-36, GHQ, and their dimensions. The combined intervention had higher effects compared to these two interventions.

Ethical Considerations
Compliance with ethical guidelines
The present study was registered by the Iranian Registry of Clinical Trials (Code: IRCT20190831044650N2), and was approved by ethics committee of Islamic Azad University, Babol Branch (Code: IR.IAU.BABOL.REC.1398.088).

Funding
This study was extracted from the MA. thesis of the fist author approved by Islamic Azad University of Babol Branch. 

Authors' contributions
Conceptualization, editing, and data analysis: Masoumeh Habibian and Babison Askari; Data collection, methodology, sampling, writing the initial draft: Nona Fazlollazadeh. 

Conflicts of interest
The authors declared no conflict of interest.


References

1. Duan L, Han L, Liu Q, Zhao Y, Wang L, Wang Y. Effects of vitamin D supplementation on general and central obesity: Results from 20 randomized controlled trials involving apparently healthy populations. Ann Nutr Metab. 2020; 76(3):153-64. [DOI:10.1159/000507418] [PMID]
2. Batrakoulis A, Fatouros IG, Chatzinikolaou A, Draganidis D, Georgakouli K, Papanikolaou K, et al. Dose-response effects of high-intensity interval neuromuscular exercise training on weight loss, performance, health and quality of life in inactive obese adults: Study rationale, design and methods of the DoIT trial. Contemp Clin Trials Commun. 2019; 15:100386. [DOI:10.1016/j.conctc.2019.100386] [PMID] [PMCID]
3. Bassatne A, Chakhtoura M, Saad R, Fuleihan GE. Vitamin D supplementation in obesity and during weight loss: A review of randomized controlled trials. Metabolism. 2019; 92:193-205. [DOI:10.1016/j.metabol.2018.12.010] [PMID]
4. Botlani Esfahani S, Pal S. Obesity, mental health, and sexual dysfunction: A critical review. Health Psychol Open. 2018; 5(2):2055102918786867. [DOI:10.1177/2055102918786867] [PMID] [PMCID]
5. Alibakhshi SZ, Alipour A, Farzad V, Aliakbari dehkordi M. [The mediating role of depression in relation between attachment and parenting style with overweight and obesity of girls adolescent (Persian)]. Q J Health Psychol. 2015; 4(13):41-52. [Link]
6. Lartey S, Si L, Lung T, Magnussen CG, Boateng GO, Minicuci N, et al. Impact of overweight and obesity on life expectancy, quality-adjusted life years and lifetime costs in the adult population of Ghana. BMJ Glob Health. 2020; 5(9):e003332. [DOI:10.1136/bmjgh-2020-003332] [PMID] [PMCID]
7. Kolotkin RL, Andersen JR. A systematic review of reviews: Exploring the relationship between obesity, weight loss and health-related quality of life. Clin Obes. 2017; 7(5):273-89. [DOI:10.1111/cob.12203] [PMID] [PMCID]
8. van Vuuren CL, Wachter GG, Veenstra R, Rijnhart JJM, van der Wal MF, Chinapaw MJM, et al. Associations between overweight and mental health problems among adolescents, and the mediating role of victimization. BMC Public Health. 2019; 19(1):612. [DOI:10.1186/s12889-019-6832-z] [PMID] [PMCID]
9. Mihailescu M, Neiterman EA. A scoping review of the literature on the current mental health status of physicians and physicians-in-training in North America. BMC Public Health. 2019; 19(1):1363. [DOI:10.1186/s12889-019-7661-9] [PMID] [PMCID]
10. Cuomo A, Maina G, Bolognesi S, Rosso G, Beccarini Crescenzi B, Zanobini F, et al. Prevalence and correlates of vitamin D deficiency in a sample of 290 inpatients with mental illness. Front Psychiatry. 2019; 10:167. [DOI:10.3389/fpsyt.2019.00167] [PMID] [PMCID]
11. Anjum I, Jaffery SS, Fayyaz M, Samoo Z , Anjum S. The role of vitamin D in brain health: A mini literature review. Cureus. 2018; 10(7):e2960. [DOI:10.7759/cureus.2960] [PMID] [PMCID]
12. Menon V, Kar SK, Suthar N, Nebhinani N. Vitamin D and depression: A critical appraisal of the evidence and future directions. Indian J Psychol Med. 2020; 42(1):11-21. [DOI:10.4103/IJPSYM.IJPSYM_160_19] [PMID] [PMCID]
13. Rozjabek H, Fastenau J, LaPrade A, Sternbach N. Adult obesity and health-related quality of life, patient activation, work productivity, and weight loss behaviors in the United States. Diabetes Metab Syndr Obes. 2020; 13:2049-55. [DOI:10.2147/DMSO.S245486] [PMID] [PMCID]
14. Jones RA, Lawlor ER, Griffin SJ, van Sluijs EMF, Ahern AL. Impact of adult weight management interventions on mental health: A systematic review and meta-analysis protocol. BMJ Open. 2020; 10(1):e031857. [DOI:10.1136/bmjopen-2019-031857] [PMID] [PMCID]
15. Vancini RL, Rayes ABR, Lira CAB, Sarro KJ, Andrade MS. Pilates and aerobic training improve levels of depression, anxiety and quality of life in overweight and obese individuals. Arq Neuropsiquiatr. 2017; 75(12):850-7. [DOI:10.1590/0004-282x20170149] [PMID]
16. Sui X, Laditka JN, Church TS, Hardin JW, Chase N, Davis K, et al. Prospective study of cardiorespiratory fitness and depressive symptoms in women and men. J Psychiatr Res. 2009; 43(5):546-52. [DOI:10.1016/j.jpsychires.2008.08.002] [PMID] [PMCID]
17. Chekroud SR, Gueorguieva R, Zheutlin AB, Paulus M, Krumholz HM, Krystal JH, et al. Association between physical exercise and mental health in 1·2 million individuals in the USA between 2011 and 2015: A cross-sectional study. Lancet Psychiatry. 2018; 5(9):739-46. [DOI:10.1016/S2215-0366(18)30227-X] [PMID]
18. Pearl RL. Weight bias and stigma: Public health implications and structural solutions. Soc Issues Policy Rev. 2018; 12(1):146-82. [DOI:10.1111/sipr.12043]
19. Wang Y, Chen Z, Wu Z, Ye X, Xu X. Pilates for overweight or obesity: A meta-analysis. Front Physiol. 2021; 12:643455. [DOI:10.3389/fphys.2021.643455] [PMID] [PMCID]
20. Tepper S, Dabush Y, Shahar DR, Endevelt R, Geva D, Ish-Shalom S. Vitamin D status and quality of life in healthy male high-tech employees. Nutrients. 2016; 8(6):366. [DOI:10.3390/nu8060366] [PMID] [PMCID]
21. Farhud DD, Mehrabi A, Sarafnejad A, Sadeghipour HR, Rahimiforoushani A, Rokni MB, et al. A comprehensive, epidemiological and ecological descriptive study on vitamin D status in Iran (308005 people, from 2009-2018). Iran J Public Health. 2019; 48(4):644-54. [DOI:10.18502/ijph.v48i4.985]
22. Marzban M, Kalantarhormozi M, Mahmudpour M, Ostovar A, Keshmiri S, Darabi AH, et al. Prevalence of vitamin D deficiency and its associated risk factors among rural population of the Northern Part of the Persian Gulf. BMC Endocr Disord. 2021; 21(1):219. [DOI:10.1186/s12902-021-00877-5] [PMID] [PMCID]
23. Khodadost M, Habibian M. [Investigating the changes of tumor necrosis factor-a and iInterleukin-10 after 8 weeks of regular pilates exercise and vitamin D intake in overweight men. A randomized clinical trial (Persian)]. J Arak Univ Med Sci. 2020; 23(6):888-900. [DOI:10.32598/jams.23.6.3537.5]
24. Zar A, Alavi S, Hosseini SA, Jafari M. [Effect of sport activities on the quality of life, mental health, and depression of the individuals with disabilities (Persian)]. Iran J Rehabil Res Nurs. 2018; 4(3):31-9. [Link]           
25. Nazari S, Honarmand P, Hoshyar Badanesh M. Comparison of the effect of yoga and pilates training on mental health and quality of life of disabled elderly women. J Psycho Sci. 2020; 18(82):1161-9. [Link]
26. Pereira-Santos M, Costa PR, Assis AM, Santos CA, Santos DB. Obesity and vitamin D deficiency: A systematic review and meta-analysis. Obes Rev. 2015; 16(4):341-9. [DOI:10.1111/obr.12239] [PMID]
27. Parva NR, Tadepalli S, Singh P, Qian A, Joshi R, Kandala H, et al. Prevalence of vitamin D deficiency and associated risk factors in the US population (2011-2012). Cureus. 2018; 10(6):e2741. [DOI:10.7759/cureus.2741] [PMID] [PMCID]
28. Gugger A, Marzel A, Orav EJ, Willett WC, Dawson-Hughes B, Theiler R, et al. Effect of monthly high-dose vitamin D on mental health in older adults: Secondary analysis of a RCT. J Am Geriatr Soc. 2019; 67(6):1211-17. [DOI:10.1111/jgs.15808] [PMID]
29. Penckofer S, Byrn M, Adams W, Emanuele MA, Mumby P, Kouba J, et al. Vitamin D supplementation improves mood in women with type 2 diabetes. J Diabetes Res. 2017; 2017:8232863.[DOI:10.1155/2017/8232863] [PMID] [PMCID]
30. Bahrami A, Mazloum SR, Maghsoudi S, Soleimani D, Khayyatzadeh SS, Arekhi S, et al. High dose vitamin D supplementation is associated with a reduction in depression score among adolescent girls: A nine-week follow-up study. J Diet Suppl. 2018; 15(2):173-82. [DOI:10.1080/19390211.2017.1334736] [PMID]
31. Callegari ET, Reavley N, Gorelik A, Garland SM, Wark JD, Safe-D study team. Serum 25-hydroxyvitamin D and mental health in young Australian women: Results from the safe-D study. J Affect Disord. 2017; 224:48-55. [DOI:10.1016/j.jad.2016.10.002] [PMID]
32. Chu F, Ohinmaa A, Klarenbach S, Wong ZW, Veugelers P. Serum 25-hydroxyvitamin D concentrations and indicators of mental health: An analysis of the Canadian health measures survey. Nutrients. 2017; 9(10):1116. [DOI:10.3390/nu9101116] [PMID] [PMCID]
33. Berridge MJ. Vitamin D cell signalling in health and disease. Biochem Biophys Res Commun. 2015; 460(1):53-71. [DOI:10.1016/j.bbrc.2015.01.008] [PMID]
34. Patrick RP, Ames BN. Vitamin D and the omega-3 fatty acids control serotonin synthesis and action, part 2: Relevance for ADHD, bipolar disorder, schizophrenia, and impulse behavior. FASEB J. 2015; 29(6):2207-22. [DOI:10.1096/fj.14-268342] [PMID]
35. Eyles D, Almeras L, Benech P, Patatian A, Mackay-Sim A, Mcgrath J, et al. Developmental vitamin D deficiency alters the expression of genes encoding mitochondrial, cytoskeletal and synaptic proteins in the adult rat brain. J Steroid Biochem Mol Biol. 2007; 103(3-5):538-45. [DOI:10.1016/j.jsbmb.2006.12.096] [PMID]
36. Khairandish R, Hashemi A Abedanzadeh R, Ranjbar R. [The effect of pilates training on some psychological factors and their relation with body mass index of passive obese (Persian)]. Q J Health Psychol. 2018; 8(29):119-33. [DOI:10.30473/HPJ.2019.37312.3806]
37. Jamali Brayjani S, Rahnama N, Abrishamkar S. [The effect of eight weeks pilates exercises on pain and quality of life in patients with spondylolysis (Persian)]. Pars J Med Sci. 2019; 17(1):33-41. [DOI:10.52547/jmj.17.1.33]
38. Akbaş E, Ünver B. A six-week pilates exercise protocol for improving physical and mental-health-related parameters. Malaysian J Mov Health Exerc. 2018; 7(2):65-79. [DOI:10.15282/mohe.v7i2.239]
39. Swan J, Hyland PA. Review of the beneficial mental health effects of exercise and recommendations for future research. Psychol Soc. 2012; 5(1):1-15. [Link]
40. Lloyd BA, Hake HS, Ishiwata T, Farmer CE, Loetz EC, Fleshner M, et al. Exercise increases mTOR signaling in brain regions involved in cognition and emotional behavior. Behav Brain Res. 2017; 323:56-67. [DOI:10.1016/j.bbr.2017.01.033] [PMID] [PMCID]
41. Mikkelsen K, Stojanovska L, Polenakovic M, Bosevski M, Apostolopoulos V. Exercise and mental health. Maturitas. 2017; 106:48-56. [DOI:10.1016/j.maturitas.2017.09.003] [PMID]

42. Khosravi ZS, Kafeshani M, Tavasoli P, Zadeh AH, Entezari MH. Effect of vitamin D supplementation on weight loss, glycemic indices, and lipid profile in obese and overweight women: A clinical trial study. Int J Prev -Med. 2018; 106:48-56. [DOI:10.4103/ijpvm.IJPVM_329_15] [PMID] [PMCID]
43. Martínez-Sánchez SM, Martínez-García C, Martínez-García TE, Munguía-Izquierdo D. Psychopathology, body image and quality of life in female children and adolescents with anorexia nervosa: A pilot study on the acceptability of a pilates program. Frontiers Psychiatry. 2020; 11:503274. [DOI:10.3389/fpsyt.2020.503274] [PMID] [PMCID]