The purpose of the study is to investigate the interaction between orthorexia and general anxiety symptoms and the tendency to use nutritional supplements during the semi-quarantine period due to the COVID-19 pandemic. We also sought to the psychological impact of social media news about COVID-19 and nutrition. We achieved five fundamental results: (1) A positive association was found between Orthorexia and generalized anxiety disorder symptoms, with the fact that these disorders were reasonably high in both sexes during the COVID-19 semi-quarantine; (2) Individuals in semi-quarantine spent an average of 52 minutes on social media seeking information about COVID-19, health and nutrition; (3) A significant positive link was observed between social media use and orthorexic symptoms in both sexes; (4) A positive interaction was obtained between general anxiety disorder symptoms and social media use; (5) Most people in semi-quarantine (an average of 51.6 %) decided to take supplements believing they support their immunity, and a positive interaction was observed between orthorexic symptoms and multivitamin and ß-glucan use in both sexes. A positive correlation was also found between orthorexia symptoms and the use of Pelargonium Sidoides, vitamin C, and D in women.
Our results suggest increased orthorexia (67.0 % in men and 83.2 % in women) and general anxiety disorder (62.6 % in men and 95.4 % in women) risks for individuals in the COVID-19 pandemic. The unexpected coronavirus pandemic has made extraordinary changes in physical and psychological health by being isolated from almost everyone and creating fear of contracting the disease . Although the COVID-19 lockdown provides better protection to prevent catching the virus, its impact on mental health has been reported to drive individuals into depression, anxiety, stress, and even suicide [4,24,25]. Our study revealed a higher percentage of anxiety compared to the world anxiety prevalence (3.6%) , and previous studies using the same GAD-7 questionnaire in China (22.6%) , Brazil (23.3%) , and Ireland (20.0%) . Higher anxiety may also be due to economic instability, as noted by Puccinelli et al . As higher anxiety levels have highly compromised mental health and closely related to eating disorders [23,25], early detection and underlying problems need to be deeply considered.
As it is claimed that mental distress such as loneliness and boredom trigger eating disorders and the COVID-19 pandemic also prompts this mood , a series of studies have been conducted to investigate the potential effect of COVID-19 on eating disorders [29–32]. Previous research has indicated that individuals with psychological distress tend to eat more, leading to emotional  and binge eating symptoms [31,32]. A study of 5,469 participants found that self-reported dietary restriction, binge eating and purging behaviours increased in 64.5%, 35.5% and 18.9% of the participants, respectively . Elmacıoğlu et al.  stated that emotional eating and uncontrolled eating behaviours had significantly increased during the COVID-19 isolation, however; no alteration was observed in cognitive restrictive behaviours. However, these studies commonly focused on the presence of binge eating and emotional eating symptoms. A recent review by Rodgers et al.  noted that orthorexic symptoms may increase due to the rise in concerns about healthy eating during the COVID-19 outbreak. We conducted the survey at the beginning of the COVID-19 pandemic (i.e., approximately one month after the semi-quarantine announcement by the Ministry of Health), when the fear of getting the disease and the unknowns about the disease are most intense, revealing that people had experienced orthorexia symptoms even at the beginning of the COVID-19 pandemic.
Orthorexic symptoms not only affect psychotic well-being  but may also create an undesirable energy deficit  that weakens immunity. Since there is a possibility that the symptoms of eating disorders developed/ or increased during COVID-19 may last for a lifetime, it is crucial to diagnose these nutritional disorders in time. However, it has previously stated that the orthorexia diagnosis is rather complicated due to the lack of certain criteria for diagnosis . In addition, as exercise habits weaken during the pandemic , individuals may restrict their daily diet consumption. Orthorexia development may be overlooked, as orthorexic behaviours and dietary restriction behaviours to avoid weight gain during the pandemic appear quite similar. As we found that general anxiety was closely related to orthorexia in both sexes, evaluating individuals identified as having general anxiety during COVID-19 pandemic in terms of the presence of orthorexia may be an effective strategy as it can provide early intervention to effectively manage the process. This strategy can be also recommended for early detection of general anxiety in the presence of orthorexia symptoms.
To our knowledge, this is the first study to investigate orthorexia and general anxiety disorder by questioning the use of social media and nutritional supplements. In line with other studies [25,29,33], we reported that nearly all participants (99.2 %) were constantly using social media. It has been shown that constant exposure to social media during the COVID-19 may have paramount effects on psychological state . In a study evaluating the interaction between the social media use and orthorexia, Turner and Lefevre  reported that a significant interaction between orthorexia and social media use, and Instagram is the most commonly used application to follow a healthy eating environment. Similar results were obtained from our study indicating that Instagram was the most frequently used application for both sexes (73.2% in men, 89.9% in women). The significant interaction between social media use and orthorexia symptoms may be due to the higher exposure time to Instagram. Following or interacting with like-minded individuals using social media can lead to an echo chamber effect, which reinforces the correctness of their point of view regarding eating behaviours by constantly underlining common views . In addition, the restrictions of nearly all outdoor activities and daily schedules during the pandemic led to intense exposure to news about COVID-19 and healthy eating on social media , thus increasing fears of contracting COVID-19, and rising the obsession about healthy eating.
We revealed that the main reason why individuals in COVID-19 pandemic chose to take nutritional supplements was to support their immunity. Rising concerns about healthy eating during the pandemic  may drive individuals to take these supplements to improve adaptive immunity to minimize the risk of contracting COVID-19. In addition, one of the major reasons why individuals increase their use of nutritional supplements without consulting any healthcare professional during the COVID-19 pandemic may also be the echo effect of social media.
Studies of orthorexia and dietary supplement use have revealed conflicting results [19,34,38,39]. Although the general belief is that dietary supplement use is significantly higher in people with orthorexia symptoms , most of the studies have indicated no significant interaction between dietary supplement use and orthorexia symptomatology [19,34,38]. In contrast to most studies [19,34,38], we found a meaningful positive association between multivitamin and ß-glucan use and orthorexia symptoms in both sexes, indicating that individuals with orthorexia symptoms tend to use multivitamins (R2 = 0.377 in men; 0.055 in women) and ß-glucan (R2 = 0.379 in men; 0.199 in women) to support their immunity and become healthier during the COVID-19 pandemic. In addition, we found that as orthorexia symptoms increased in women, the use of Pelargonium Sidoides (R2 = 0.172), vitamin C (R2 = 0.142) and D (R2 = 0.199) also increased. Although the main purpose of supplement use is to support immunity, it should be kept in mind that it may affect the body in the opposite direction, especially in the case of COVID-19 . Nutritional supplements mainly zinc, selenium, vitamin C, and D have been applied to attenuate the severity and duration of viral diseases; however; the efficiency of nutritional supplements were still controversial [40,41]. Although there is no evidence-based consensus regarding recommendation of nutritional supplements during COVID-19, social media and supplementary industry have been bombarding a variety of nutritional supplement recommendation to improve immunity and, thereby, prevent COVID-19 infection. In addition, the possible effects of nutritional supplements on cytokine storm should also need to be evaluated. Although it is well known that both cytokines and chemokines have great effects on the innate immune response during viral infections as the first guardian of the body's defence against the virus, excessive production of these molecules during the viral infections may induce immunopathology, causing a cytokine storm that may lead to several detrimental consequences including attenuated T cell response, enhanced vascular leakage, and impaired virus clearance . It is unclear how nutritional supplements affect the occurrence or presence of cytokine storm. Therefore, we need randomize-controlled clinical trials to better understand the impact of nutritional supplements on the body defence . Several research [41,42] and reviews [43–45] have been conducted to unveil the unknowns of nutritional supplements during COVID-19. In a randomized clinical trial investigating the efficiency of high dose zinc and/or ascorbic acid supplements in outpatients with the COVID-19 infection, Thomas et al.  indicated that administration of high-dose zinc (50 mg) and ascorbic acid (8000 mg) supplements alone or in combination did not reduce the duration and severity of symptoms. Similar with the study, in a longitudinal app-based study of 327,720 UK subjects revealed that no potential impact of zinc, vitamin C, or garlic supplements were observed in both sexes regarding of the COVID-19 risk . However, it was also stated that individuals taking multivitamins, omega-3 vitamin D and probiotics had lower risk of COVID-19 infection by 13%,12%, 9% and 14%, respectively. This results may be promising for the use of multivitamins, omega-3, probiotics, and vitamin D; however; due to the nature of this study, health professionals need more scientific clarification to recommend their supplementations to individuals . In addition, checking the national dietary guidelines before recommending any nutritional supplements during the COVID-19 pandemic is also a great strategy to eliminate misutilization of these supplements. Coelho- Ravagnani et al.  outlined the current dietary guidelines for COVID-19, underlining that nutritional supplements, such as zinc, vitamins C, A, and D may be applied to improve immunity in case of any deficiency is detected.
Since the beginning of the pandemic, researchers particularly focused on the potential efficiency of vitamin D on COVID-19 infection due to its modulatory mechanisms on immunity by dampening the entry and replication of the coronavirus and attenuating proinflammatory cytokines and provoking production of anti-inflammatory cytokines to fight the virus . A systematic review and meta-analysis by Bassatne et al.  has underlined that high quality studies are needed before implementing vitamin D supplementation to treat or prevent the infection, although there is a pattern between vitamin D deficiency and COVID-19 outcomes. All studies considered, even vitamin D supplementation is only recommended for people with low vitamin D status or limited access to sunlight . Furthermore, the risks of taking high doses of vitamin D have also been highlighted due to potential harmful effects on health, especially in individuals with other health problems such as decreased kidney function . Therefore, individuals should be cautioned that a detailed nutritional evaluation is necessary to determine if there is a nutritional deficiency before starting any nutritional supplements during the COVID-19 pandemic and that otherwise supplements may cause detrimental effects on health.
Our study has several strengths and limitations to consider. To our knowledge, this is the first study to compare orthorexia nervosa and anxiety in relation with the use of social media and nutritional supplements. The use of an online survey enabled data to be collected from all over the country. We implemented the ORTO-11, the valid and reliable version of ORTO-15 in our country as it eliminates the false prediction of the disorder. It is crucial to apply a valid questionnaire since we are aware that one of the main reasons why orthorexia is not included in DSM-V is the psychometric limitations of the ORTO-15 questionnaire, such as lack of cultural adaptation, internal validity, and reliability.
Since there are no specific diagnostic criteria for orthorexia in DSM-5  and we cannot independently be confirmed the presence of eating disorders, we did not ask if they had been diagnosed with orthorexia or any eating disorders before. However, previous eating disorder history may elevate the exaggerated obsession about food and orthorexic behaviours during the COVID-19 pandemic.