Introduction

Eating disorders (EDs) have multiple risk and maintenance factors. There are various guidelines and seminal articles urging further research and treatment developments in the field. Throughout the last two decades, biological and genetic research in the ED field has flourished, leading to an improved understanding of aetiology and potential targets for treatment. Unfortunately, research studies investigating the social aspects of EDs, including the needs of patients from international communities outside of Western Europe and North America, have been scarce.

Acculturation has primarily been defined as “the process of psychosocial change that occurs when a group or individual acquires the cultural values, language, norms, and behaviours of dominant society” (as cited in Wildes et al. [37], p. 524). The aim of this paper is to provide a systematic review of the literature from the last two decades, summarizing evidence regarding whether culture change, either as a result of immigration and acculturation or changes within a culture, leads to elevated levels of ED symptoms and increased risk of developing an ED. Specifically, we will endeavour to examine the impact of Western culture on the occurrence of EDs. The rationale for this is that fashionable emphasis on slenderness and conflicting expectations that lead to extreme identity confusion in young women have long been identified as critical factors in the development of eating disorders [6]; and furthermore, have been associated with the increased prevalence of eating disorders in Western cultures [17].

Since their inception, ED classification systems within the Diagnostic and Statistical Manual of Mental Disorders (DSM; American Psychiatric Association [2]) have routinely undergone revision. The most recent version of the DSM (5) has modified the criteria for ED diagnoses such that they are more relaxed and inclusive. This may stem from the difficulties in identifying steady cross-cultural patterns of EDs, and stresses the importance of further research regarding the epidemiology and cross-cultural presentation of disordered eating.

For a long time, Anorexia Nervosa (AN) and Bulimia Nervosa (BN) were considered disorders characteristic of ‘Western’ women as the first studies were primarily based on North American and Western European data. However, studies carried out during the last few decades in Asia, Africa, and Eastern European countries have changed this perspective. In the 1990s, several studies demonstrated that the incidence of EDs among young Asian women who had immigrated to the United States or Western Europe was considerably higher than was previously thought [12]. According to Di Nicola [13], AN develops when there is a high level of stress associated with cultural assimilation; this point was also emphasized by Geller and Thomas [16].

At present, multiple authors believe that culture change is a key factor associated with the development of EDs. Miller and Pumariega [29] reviewed evidence of EDs among Western and ethnic minority groups. They examined the role of cultural change in the development of disordered eating and suggested that culture change, such as via immigration, may be associated with increased vulnerability to EDs. In a qualitative study of young Czech female au-pairs living abroad [31], it was found that sojourning abroad and the associated loneliness were significant factors in developing an ED.

In this systematic review, we were interested in exploring the current thinking and empirical data on the association between ED symptoms and acculturation, particularly in the context of Western culture. For this purpose, we focused predominantly on research articles published since the year 2000.

Methods

This review follows the PRISMA statement for reporting systematic reviews and meta-analyses [27]. The following electronic databases were used to identify relevant papers for inclusion in this review: PubMed and SCOPUS. A preliminary search was conducted in August 2014 and this was subsequently updated in February 2015.

A broad search was first run on the literature using the terms “Culture”, “Acculturation” and “Eating disorders” (including “Anorexia” and “Bulimia”). The search was conducted by three researchers (ED, IS and KT) seeking published studies on the basis of the following inclusion criteria:

  • A sample of greater than 10 participants

  • Measures of acculturation or ethnic identity

  • Measures of eating disorder symptoms

  • Published in English peer-reviewed journals

Results from these searches were merged for higher reliability. Following the initial identification of relevant published articles, all citations were then obtained. Further relevant references cited in the retrieved papers were pursued.

For the purposes of this review, we selected research articles that primarily looked at the influence of adjusting to a different culture with Western ideals, which encompassed the adjustment of individuals as well as the adjustment of communities in a broader sense, going beyond individual experiences of cultural change and capturing factors such as biculturalism and immigrant generational status. Some of the studies reviewed compared ED prevalence between the immigrant group and corresponding ethnic group residing in their original non-Western countries, which, to a certain degree, also touched the issue of ED development in non-Western countries. In addition, a few studies examined the impact of Western culture within a non-Western country, on the development of ED pathology. We excluded studies examining the differences in ED pathology between ethnic groups within a given country and where culture change or the effects of westernization are not considered.

Furthermore, we have not included studies that investigated more general eating behaviours or attitudes towards weight or shape, as the focus of this review is on disordered eating with a focus on weight reduction (i.e. AN and BN). Thus, we also excluded papers reporting on binge eating disorder.

Results

We have reviewed 25 articles reporting on studies that attempted to identify links between EDs or disordered eating patterns on the one hand, and acculturation and culture change on the other (a PRISMA consort diagram is presented in Fig. 1 and Table 1 contains the reviewed studies with their relevant details). The majority of the publications were found in eating disorder-specific journals, most commonly the International Journal of Eating Disorders, while others were found in more general psychology journals. Based on the findings produced by the studies (Table 1), these articles can be divided into three categories: those that examine the relationship between EDs and culture change/acculturation and (A) suggest considerable association between EDs and culture change/acculturation; (B) suggest little or no association between EDs and culture change/acculturation; (C) do not primarily discuss the association between EDs and culture change/acculturation, yet generate valuable insight on the subject. The studies reviewed varied in terms of the methodologies used to measure the degree of acculturation and the presentation of disordered eating patterns. In this regard, more consistency was observed in assessing ED symptomatology than in identifying the degree or extent of acculturation/culture change.

Fig. 1
figure 1

Consort diagram detailing the study selection process

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Table 1 Table detailing the research articles identified which examine the association between culture change/acculturation and eating disorder symptoms, according to the criteria outlined in the “Method” section
Full size table

Considerable association between EDs, acculturation and culture change

Multiple authors [8, 10] have pointed out the role of embracing Anglo-cultural orientation in the development of disordered eating among Mexican Americans. According to Chamorro and Flores-Ortiz [10], the increased orientation towards Anglo-American culture among Mexican American women in the US was related to the development of EDs (N = 139 adult females; mean age = 29.1; 57.6 % had been in the US since birth; 36 %, first generation; 37.4 %, second generation); furthermore, their findings suggested that second-generation immigrants were at higher risk of developing EDs as they exhibited both the most disordered eating patterns and the highest degrees of acculturation. Cachelin and colleagues [8] reported a similar pattern with regard to the influence of culture on the development of EDs; however, they found no relationship between the presence of EDs and generational status (N = 188 adult females; aged 18–48; 79 with eating disorders and 109 controls).

Furthermore, Ball and Kenardy [3] identified a positive association between the length of time spent by immigrant women in Australia and the presence of weight-related values and behaviours similar to those of Australian-born women (N = 14,779 adult females; aged 18–23; a community sample randomly selected from the national healthcare database). Consistent with these findings, a study from Israel [19] revealed that native-born Israeli and veteran immigrant women were more likely to exhibit ED symptoms than were women who had immigrated more recently (N = 499 higher education students; 281 females, 218 males; aged 18–24 with mean age = 23; 216 Israeli natives, 153 3 years or fewer immigrants and 130 veteran immigrants).

On the other hand, findings from a study conducted in Spain by Esteban-Gonzalo and collaborators [14] found a greater risk of EDs in adolescent female immigrants living in Spain for fewer than 6 years compared to the risk in female natives and female immigrants living in the country for more than 6 years (N = 2077 adolescents; 1052 females, 1025 males; aged 13–17); thereby suggesting that lengthier residence, or greater acculturation, is a protective factor against the development of EDs in adolescents (it should be noted, however, that 80 % of the immigrant population in this study represented immigrants from Latin American countries who are native Spanish-speakers). Similarly, a study carried out in Australia by Jennings and colleagues [23] revealed that less acculturated Asian adolescent females aged 14–17 exhibited greater ED psychopathology than those who were more acculturated (N = 42 non-clinical adolescent girls; aged 14–17; 17 Asian and 25 Caucasian). This led to the authors concluding that ED psychopathology may be the result of an individual’s attempt to identify with two different cultures and that the decreased rates of illness over time may be explained by the fact that the less acculturated group is still adjusting to the dominant culture, while the more acculturated group is more at ease.

Interestingly, while studying the effect of acculturation on body image and risk of ED among various groups (Eastern European, Chinese and Afro-Caribbean) of immigrant women in the United States, Sussman et al. [35] found that long-term acculturation over generations was associated with increasingly negative health consequences for women of Eastern European descent and increasingly positive outcomes for women of Chinese and Afro-Caribbean descent (N = 353 female undergraduate students; aged 18–67 with mean age = 23.7; 187 first generation with 46 Chinese, 88 Afro-Caribbean and 53 Eastern European heritage; 36 second generation with 15 Chinese, 15 Afro-Caribbean and 6 Eastern European heritage; 130 third generation with 84 European-American and 46 African-American heritage). In other words, acculturation was found to be a risk factor only among women of Eastern European descent, who also, compared to the women of Afro-Caribbean descent, were more likely to adapt to an American identity. Thus, the authors concluded that ethnicity had a discernible moderating effect on the impact of acculturation on risks for an ED.

Little or no association between EDs, acculturation and culture change

Some authors [15, 34] have suggested that eating concerns are not associated with acculturation to Western culture. A study by Soh et al. [34] on eating concerns among North European and East Asian (Chinese, Vietnamese, Korean and Singaporean) women with and without an ED in Australia and Singapore found that women with an ED had similar levels of psychopathology across the cultural groups and eating concerns were not associated with cultural group overall or acculturation to Western culture (N = 154 adult females; aged 14–38; with and without an ED; born in Australia or migrated to Australia by the age of 12).

Another study exploring disordered eating and degree of acculturation among Asian and Caucasian adolescent girls in Australia [24] found no significant differences between the racial groups or between the more acculturated and less acculturated Asian girls, thus suggesting that the level of acculturation does not modify susceptibility for developing an ED (N = 240 adolescent females; aged 18–24; 130 Asian and 110 Caucasian). Consistent with these findings, Abdollahi and Mann [1] reported that acculturation to Western norms did not appear to be related to symptoms of disordered eating in Iranian women in Iran and America (N = 104 female students; 59 Iranian living in Tehran and 45 of Iranian decent living in Los Angeles).

Valuable insight into the association between EDs, acculturation and culture change

A study on the development of eating pathology in Chinese-Australian women [20] examined the relationship between acculturation and eating pathology and found both similarities and differences between the more acculturated and less acculturated groups: specifically, those who reported the highest levels of eating pathology were acculturated women who perceived higher levels of pressure from their fathers and best male friends to lose weight, and traditional women who experienced higher levels of parental care (N = 81 Chinese-Australian women with a mean age of 28.6). Another study [5] on Asian immigrants found that acculturation was related to only certain facets of eating concerns, thereby emphasizing the importance of assessing the psychologically relevant facets of culture versus the global construct of westernization (N = 150, 75 males, 57 females; non-clinical East Asian immigrants). A qualitative exploration of young Czech au-pairs [31] generated valuable insight on how the individual conditions, such as feelings of boredom and isolation, of women temporarily residing in a foreign country (not immigrants) may exacerbate acculturative stress and ED risks (six semi-structured interviews with adult females with an ED and history of sojourning abroad, aged 20–27, and seven first-person internet testimonies analysed).

Discussion

The aim of this study was to synthesize the literature from the last two decades on the association between ED symptoms and acculturation, particularly in the context of Western culture. The majority of the evidence reviewed here suggests that there is a notable association between culture change and ED psychopathology. Interestingly, while some studies have found that greater acculturation is associated with increased susceptibility to developing an ED, others have identified that less acculturated individuals are more vulnerable to EDs. Furthermore, the nature of the association appears to be largely dependent upon the group studied, and how acculturation and culture change are defined, conceptualized and measured.

Examination of the methodologies utilized by the studies included in this review showed that measures of acculturation varied significantly both conceptually and architecturally, which may in part explain the inconsistencies in findings. While a few studies used ‘length of residence’ (LOR) as a measure of acculturation, most studies utilized uni-dimensional or bi-dimensional models. Uni-dimensional measures of acculturation place individuals on a linear continuum of identities ranging from exclusively heritage oriented to exclusively mainstream oriented, while bi-dimensional models treat cultural maintenance and adoption as two distinct dimensions, thereby allowing for the possibility of having two or neither cultural identities [9, 25].

Berry and colleagues (cited [25]) identified four types of acculturation style: integration (interest in maintaining both cultural identities); assimilation (interest in maintaining only mainstream cultural identity); separation (interest in maintaining only original cultural identity); and marginalization (little interest in maintaining either cultural identity). According to Berry [4], while there are individual differences in how people experience acculturation, those pursuing the integration strategy generally experience less stress and achieve superior adaptation outcomes. This suggests that healthy acculturation is contingent on maintaining two cultural identities.

If we rely upon this theory and assume that the healthiest style of acculturation is through integration, then studies using uni-dimensional models which identify individuals as being “more acculturated” may mean that they are either more assimilated or more integrated. For instance, the two aforementioned studies on Mexican Americans [8, 10] which produced somewhat conflicting findings about the same group with regards to generational status and ED, employed different measures of acculturation: while the former utilized a uni-dimensional measure (the Acculturation Rating Scale for Mexican Americans, which differentiates between five levels of acculturation from Very Mexican to Very Anglicized), the latter used a bi-dimensional measure (the Acculturation Rating Scale for Mexican Americans––II). It is clear that in linear, or uni-dimensional, measures, “assimilated” individuals would most likely score highly, whereas “integrated” individuals would not. This demonstrates the distinction between “healthy acculturation” and “high acculturation”, and the inconsistencies stemming from different measures of acculturation utilized by different researchers, which might partly explain the conflicting findings in this review.

Another important point is that when referring to acculturation, many researchers have applied the term in reference to Western culture, whereas change from Western to non-Western culture, to our knowledge, has not been studied in relation to ED psychopathology. While many authors have argued that increased exposure to Western culture may facilitate the development of EDs, it is quite possible that culture change per se, and not just acculturation to Western culture, is a contributing factor. Besides, researchers need to be clear and consistent in how they define “Western” and “non-Western”. Furthermore, the proximity (perhaps both geographical and cultural) between origin and host cultures also seems to be an important factor to consider. In their study on immigrants in Madrid, Esteban-Gonzalo et al. [14] found a greater risk of EDs in adolescent female immigrants living in Spain for fewer than 6 years compared to the risk in female natives and female immigrants living in the country for more than 6 years. However, 80 % of the immigrants studied happened to be from Latin American countries and, therefore, native Spanish-speakers, which limits the generalizability of these findings.

Considering the heterogeneity of our findings, it seems important that future studies track and differentiate certain key demographic factors which significantly influence how people experience culture change. None of the studies reviewed here examined the importance of immigrant characteristics such as voluntary versus forced immigration, immigration with family versus alone, or legal versus illegal immigration. These factors are likely to interact with acculturative stress and are therefore highly relevant for the first, and perhaps subsequent, generations of immigrants. Furthermore, these findings highlight the importance of forming a cross-culturally acceptable definition of the term ‘ethnicity’. For instance, in the study by Sussman et al. [35], ‘Eastern-European’ is presented as an ethnicity although it pertains to a region with more than 20 different ethnicities.

Overall, the variety of findings discussed in this systematic review clearly indicates that researchers need to separate out the different domains of acculturation and examine more precisely how they are each related to certain facets of eating concerns. It seems critical to explore the process of culture change/being exposed to a dominant foreign culture, and carefully define the stage at which the individual is at a given time. It also appears important to explore the situation in which he/she is at a given moment, and examine associated adjustment stress and mental health risks. Assessing how the individual is coping with being torn between two cultures seems crucial, and inter-cultural proximity may also be a factor to consider.

In conclusion, further research is warranted to: (a) explore the presentation of disordered eating in different cultures and form cross-culturally acceptable definitions and measures of problematic eating; (b) examine the various facets of culture change and refine the definitions of healthy and high acculturation; (c) study and generate valuable findings on the relationship between EDs and the process of acculturation to Western culture; and (d) most importantly, inform professional communities, policy makers and the general public on the risks and coping skills associated with culture change and acculturation.