Adherence to dietary recommendations (DR) remains a challenge for the majority of Americans for a number of reasons including taste preferences, limitations in nutrition education or food preparation knowledge, or most importantly, the systemic barriers leading to inequitable access to healthy food. It is well established that racial/ethnic minorities and those at lower income levels in the USA have poorer diet quality compared with whites and individuals at higher income levels(Reference Kris-Etherton, Petersen and Velarde1,Reference Rehm, Peñalvo and Afshin2) . One dimension that has been less explored is the potential limitation of existing DR in considering diverse cultural values around food that may consequently compromise nutritional intake. Increasingly, immigrant communities – a large proportion which are Latina/x/o and Asian in the USA – maintain culinary traditions that are diverse and differ widely from a typical American dietary pattern(Reference Azar, Chen and Holland3–Reference Kandula, Ahmed and Dodani7). The cultural dimension of eating, which is crucial for staying connected with cultural identity and community(Reference Peres8), has rarely been accounted for related public health guidance, including the Dietary Guidelines for Americans (DGA)(Reference Fischler9–Reference Mukherjea, Underwood and Stewart11).
Cultural adaptation can potentially bridge the gap between existing DRs and health equity(Reference Barrera, Castro and Strycker12). Additionally, we put forth the notion that some recommendations may be more readily adapted to different cultures than others without significant increase in financial burden. With a focus on the diverse population in the USA, this commentary first briefly describes salient features of the DGA, then against this backdrop describes the specific content, origin, purpose and level of adaptability from prior cultural adaptations of the Dietary Approaches to Stop Hypertension, the Mediterranean Diet, the EAT-Lancet diet and the NOVA classification system. Similar to DGA, these widely used and emerging DR (i.e. patterns and frameworks) in the USA focus on physical well-being and lack attention to the cultural perspective that contributes to social and emotional health(Reference Appel, Moore and Obarzanek13–Reference Willett, Rockström and Loken15). We conclude with suggestions for broadening the scope of cultural adaptation towards sustainable behavioural changes for nutritional health and general well-being among the racial/ethnic minority populations.
Dietary guidelines for Americans
An overview of DGA is included in Table 1. While the DGA suggest considerations of ‘personal preferences, cultural traditions, and budgetary conditions’(16), the recommendations are based on the intake of the general US population – data which underrepresent the preferences of diverse racial/ethnic minority subgroups(17). Further, the DGA emphasise foods based on their nutrient density for the benefit of reducing disease risks(16) – which runs counter to foodways of other cultures that prioritises social connections(Reference Peres8). In other words, compliance to DGA means (1) prioritising physical health over social and emotional health and (2) adhering to a dietary pattern that does not account for cultural dimension, and therefore disproportionately impacts minorities in the USA. Lastly, the DGA inform federally funded food and nutrition programmes that disproportionately serve racial/ethnic minorities(Reference Scrinis18,Reference Barco Leme, Fisberg and Baranowski19) , yet the mismatch of eating behaviours and preferences and reductionist nutrition in the absence of sociocultural influences may be inadequate to improve nutrition in these groups.
Table 1 Purpose, specific content, and origin and evolution of popular and emerging dietary recommendations in the United States
Cultural adaptability of popular and emerging dietary recommendations
We describe four dietary patterns or frameworks in terms of their cultural adaptability with detailed descriptions of each dietary recommendation and its origin and evolution provided in Table 1.
Dietary approaches to stop hypertension
The DASH diet embodies a public health mission of addressing hypertension, implying its explicit emphasis on the absence of a specified disease and not the maintenance of well-being of a general population(Reference Appel, Moore and Obarzanek13).
Cultural adaptation of DASH is straightforward for food group recommendations but less so with nutrients(Reference Appel, Moore and Obarzanek13). Individuals lack data on nutrient composition of cultural foods that are not easily accessible to the public(Reference Appel, Moore and Obarzanek13), which requires substantial resources from both programme participants and implementers(Reference Kawachi, Berkman, Berkman and Kawachi22–Reference Osuna, Barrera and Strycker25). In addition to cultural adaptation of food- and nutrition-related materials, counseling sessions or food environment assessments were also included as part of the interventions. For example, two 10- to 12-week studies that each adapted DASH to Korean or Latin cultures included modifications on the unit of measure and examples of foods in each food group(Reference Kim, Song and Han20,Reference South and Phillips23) and multiple in-person and telephone sessions(Reference Kim, Song and Han20,Reference Estrada Del Campo, Cubillos and Vu21) . Another cultural adaptation of DASH was a 12-week randomised controlled pilot with African Americans by identifying traditional foods and dietary habits and including a food environment assessment of the participants’ neighbourhood(Reference Hutchins, Bouye and Luber24). These studies suggest DASH has been adapted across a number of cultures and populations and short-term health improvements. However, it is unclear whether DASH is feasible for individual- or community-level adaptation, and whether the treatment-oriented end-goal, i.e. reduce blood pressure, is appropriate for everyday use.
Mediterranean diet
Mediterranean diet (MD) is similar to DASH in its emphasis on physical health but is also recognised as an ‘Intangible Cultural Heritage of Humanity’ by the United Nations Educational, Scientific and Cultural Organization(Reference Viladrich and Tagliaferro6):
‘A set of skills, knowledge, rituals, symbols and traditions concerning…particularly the sharing and consumption of food. Eating together is the foundation of the cultural identity and continuity of communities…social exchange and communication…emphasizes values of hospitality, neighbourliness, intercultural dialogue and creativity, and a way of life guided by respect for diversity. It plays a vital role in…bringing together people of all ages, conditions and social classes…Markets also play a key role as spaces for cultivating and transmitting the Mediterranean diet during the daily practice of exchange, agreement and mutual respect.’(Reference Viladrich and Tagliaferro6)
It is noteworthy that while much of the United Nations Educational, Scientific and Cultural Organization description overlaps with multiple contextual factors which have been the focus of public health efforts in recent years – including social cohesion, community engagement and climate change(Reference Kawachi, Berkman, Berkman and Kawachi22–Reference Hutchins, Bouye and Luber24) – in the day-to-day understanding of this diet, these factors are largely absent. These upstream factors illustrate the important contexts in which MD is to be adapted, yet they are not translated into the popular version of MD, which focuses solely on food composition. Cultural adaptation of the current MD version means failure to account for the social connections with foods, which possibly compromises the benefits of following a MD in its entirety(Reference Kandula, Ahmed and Dodani7).
MD has been culturally adapted to Latina/x/o and Black populations in the USA. The studies involving Latina/x/o specified surface-structure (e.g. language, food items) and, to varying degree, deep-structure adaptations (e.g. including family members) and also indicated good acceptability from Latina/x/o participants of the adapted MD plan(Reference Estrada Del Campo, Cubillos and Vu21,Reference Osuna, Barrera and Strycker25) . The Heart Healthy Lenoir Project, which involved a majority of Black, low-income participants, culturally adapted by retaining Southeastern foods and focused on the quality of oil(Reference Keyserling, Samuel-Hodge and Pitts26). To our knowledge, no USA-based studies have adapted the MD for Asian subgroups despite their cardiometabolic risks being higher than whites and the USA general population(Reference Mukherjea, Underwood and Stewart11–Reference Willett, Rockström and Loken15). To summarise, cultural adaptations of the MD that consider social and cultural elements to some degree seem to have been met with some success for diverse groups(Reference Peres8,Reference Barco Leme, Fisberg and Baranowski19) . However, the broader question of whether it is even ‘appropriate’ to impose a cultural diet onto an entirely different culture persists.
EAT-Lancet reference diet
Similar to MD and DASH, the EAT-Lancet Reference Diet (EAT) addresses physical health both directly through individual-level food selection and indirectly through system-level food production. EAT is relatively new and therefore little evidence of cultural adaptation exists, but current research points to the fact that components of EAT may serve as barriers to cultural adaptation. A global initiative, EAT claims that the dietary pattern is applicable to all food cultures, but its scientific basis, similar to DGA, is largely and narrowly drawn from literature based in North America(Reference Willett, Rockström and Loken15). We illustrate this through three observations. First, the suggestion of EAT to consume minimal/no animal source foods overlooks the European- and Asian-based studies demonstrating benefits in consuming amounts of animal source food higher than EAT’s recommendation(Reference Leroy and Cofnas27–Reference Wang, Lin and Ouyang31). Second, the food group recommendations in EAT undercut the ‘plant-based’ diets that some cultures, such as those in Southeast Asia, have already followed throughout the millennia(Reference McMurry, Cerqueira and Connor32,Reference Imamura, Micha and Khatibzadeh33) . Lastly, the emphasis in EAT to shift to plant-based diet may create financial burden for racial/ethnic minority populations, who disproportionately experience food insecurity in an environment where plant-based foods remain more costly compared to meat or processed foods in terms of energy density(Reference Chungchunlam, Moughan and Garrick34,Reference Blisard, Stewart and Jolliffe35) . To summarise, EAT’s global reach and its considerations for environmental health through dietary change demonstrate a shift away from the focus of only physical health. Moreover, its narrow scientific evidence makes adherence to EAT less feasible for diverse communities, in some cases may be inadvisable, and takes a primarily Eurocentric/meat-based approach.
NOVA classification system
In contrast to DGA, MD, DASH and EAT that make recommendations for food groups based on their nutrient composition and density, the NOVA Classification System (NOVA) provides a framework for classifying single food items according to the level of processing. The origin of NOVA is similar, however, to the other DR in that it was developed out of concern for ultra-processed foods and their detrimental impacts on physical health(Reference Monteiro, Cannon and Levy36). NOVA is by design considerate of cultural diversity by encouraging the shift of food choices to less processed foods to opting for regional/local ingredients that are less likely to require a higher level of processing for food preservation and/or storage(Reference Monteiro, Cannon and Moubarac37). Moving away from ultra-processed foods means preserving food culture at the local level on the global landscape. No studies to date have engaged in cultural adaptation of NOVA in the USA, except for a study that suggests nutrition education involving NOVA to be appropriate for a racially/ethnically diverse group of college students(Reference Monteiro, Cannon and Levy36). In summary, despite a lack of evidence thus far, NOVA with its simple to follow message that takes into consideration sociocultural factors may be a viable option as a basis for nudging individuals towards better nutrition across multiple diverse groups.
Discussion
By 2045, the USA will become a ‘majority minority’ community(Reference Frey38), but DR do not serve all Americans equitably. They rely on evidence derived from the general USA population and/or a Eurocentric perspective, with regards to foods consumed, food choices, affordability and underlying nutrition profile. The importance of eating is reduced from a sociocultural significance to a carrier of nutrients for physical health.
The DR described in this commentary differ in their origin and evolution but are similar in their reductionist emphasis on physical health. The cultural adaptation interventions we examined here are limited by scarcity of resources and, for the most part, limited to adaptation at the surface level(Reference Frey38), which is likely due to the fact that social science literature that pertains to food and culture(Reference Fischler9,Reference Yang, Buys and Judd39,Reference Gardaphé and Xu40) is largely absent in the science base of the DR. Existing efforts through Oldways(41) and Med Diet 4·0 framework(Reference Dernini, Berry and Serra-Majem42) that go beyond the ‘physical health’ framing to embody the social and cultural aspects of MD are promising, but more difficult, time-consuming and infrastructure change efforts will be needed to operationalise such changes(Reference Yi, Lee and Russo43).
Despite the shortfalls, we are inspired by some elements of these DR and suggest four key aspects for consideration when developing DR centered on cultural orientation: (1) to address nutrition and health in the context of food and cultural studies, practices and history; (2) to actively engage racial/ethnic minorities and immigrants to explore their preferences and traditions they wish to preserve and document them to build the evidence base; (3) to distinguish dietary patterns that are for disease treatment (i.e. DASH for hypertension) from those that are for maintaining health (DGA for generally healthy Americans) or for preventing certain groups of disease (i.e. NOVA for metabolic disorders) and promote them accordingly and (4) to focus on strengths not on deficits of the racial/ethnic minority foods and culture of eating.
Adherence to the current DR may support physical health but may compromise social and emotional health(44) and, in some cases, ethnic identity and well-being(Reference Arandia, Sotres-Alvarez and Siega-Riz45). The demographic shift towards a more diverse population means our evidence base for DR needs to be reflective of the racial and ethnic diversity and associated diversity of food cultures. Given the rapidly growing interest in precision nutrition(Reference Rodgers and Collins46,Reference Zeisel47) and food as medicine(Reference Mozaffarian, Mande and Micha48,Reference Downer, Berkowitz and Harlan49) that are oriented to physical health, it is urgent that policymakers and researchers think about the values we want to preserve for future generations and the role of culture in nutrition and health without perpetuating health inequities in the USA.
Acknowledgements
Acknowledgements: We thank all the frontline workers, especially those in food services, to ensure food safety and food quality, during the ongoing coronavirus pandemic. We also thank two anonymous reviewers whose comments helped improve and clarify the manuscript. Financial support: This publication is supported by grant numbers U54MD000538 from the National Institutes of Health (NIH) National Institute on Minority Health and Health Disparities and R01HL141427 from the National Heart, Lung and Blood Institute. The contents of this publication are solely the responsibility of the authors and do not necessarily represent the official views of the NIH. Conflict of interest: There are no conflicts of interest. Authorship: V.H.-C.W. and S.S.Y. conceptualised the study. V.H.-C.W. wrote the first draft of the manuscript. V.H.-C.W., V.F. and S.S.Y. critically reviewed and approved the manuscript. Ethics of human subject participation: Not applicable.
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