In public health writing, the terms “acculturation” and “assimilation” are commonly used to mean the same thing, but it is not always clear what they mean. This lack of conceptual precision has real consequences [1]. Acculturation typically refers to how immigrants adapt to the dominant culture, while assimilation implies deeper social absorption, often requiring conformity to mainstream norms [1]. But much of the research on immigrant mental health uses these words as if they mean the same thing. Even worse, they do not always explain how they work or take power dynamics into consideration.

The difference may seem mostly academic, but the language we use changes the questions we ask. If poor health among immigrants is described as a consequence of acculturation, our attention naturally turns towards immigrants themselves: what language they speak, how they behave, what they eat, or how closely they identify with the dominant culture. That framing can make cultural adaptation appear to be the problem before we have considered what immigrants are adapting to. Discrimination, economic exclusion, food insecurity, employment conditions, and social marginalisation can all exist alongside cultural change. When all of these experiences are compressed into a single idea of “acculturation,” we risk giving a cultural explanation to what may also be a structural problem.

Schwartz et al. disagree with this simplification, saying that acculturation is not a one-way process but an interaction that involves identity, values, and surroundings [2]. Still, a number of studies in the Healthy Immigrant Effect literature employ acculturation as a stand-in for language usage or time spent in the US. Choi and Smith and Coleman-Jensen discuss how being in a place for a long time can be associated with worsening health outcomes [3], [4]. This can suggest that acculturation itself is bad for your health, which does not take into account things like discrimination, food shortages, and being left out of the economy over time [3], [4].

This is where I think we need to be much more careful about what we call acculturation. Consider time spent in the US. Someone who has lived there for twenty years may speak English fluently and participate extensively in American society while still maintaining the values, traditions, identity, and practices of their culture of origin. Another person might adopt some aspects of American culture within only a few years. Neither experience fits neatly into a scale where more years automatically means more acculturation. The same problem exists with language. English proficiency may tell us something about communication or participation, but it cannot tell us everything about someone's cultural identity. More importantly, time spent in the US does not measure cultural exposure alone. It also represents more time living within American social and economic systems. If an immigrant's health deteriorates after fifteen or twenty years, cultural adaptation is only one possible part of that story. Those years may also contain experiences of insecure employment, discrimination, difficulty accessing resources, or food insecurity [3], [4]. This is why treating duration of residence as acculturation can become misleading. Time is relatively easy to measure; culture is not. But ease of measurement should not allow one to become a substitute for the other.

This relationship becomes evident in Mendoza's discussion of children in immigrant homes [5]. He illustrates how acculturation stress, especially the differences between immigrant parents and children born in the US, might make young people more likely to act out and experience mental health challenges [5]. But this “acculturation gap” is not just cultural; it can also show how family rules and systemic expectations, like school discipline or language requirements, do not always match up [6]. For instance, some second generation Hispanic and Latinx teens report feeling culturally estranged from their parents while also navigating racial and social marginalisation within mainstream institutions [6]. Their problems may be described as identity crises, when they may also be reactions to conflicting societal pressures.

Calling this an “acculturation gap” can therefore make a complicated experience sound as though it exists entirely within the immigrant family. A young person may be negotiating expectations from their parents at home, different expectations at school, and another set of pressures from the wider society in which they are growing up. They may adapt differently from their parents without being completely accepted by the dominant culture either. The problem is not necessarily that one generation has acculturated too much and another too little. It may be that both are trying to function within social environments that demand different things from them. That distinction matters because framing shapes responsibility. If we describe the problem primarily as a cultural gap between parents and children, the obvious solution appears to involve changing how the family communicates or adapts. Those interventions may certainly be useful, but the framing can leave schools, institutions, and wider social expectations relatively untouched. The term itself can narrow our view of where the problem is located.

Some immigrant groups are sometimes called “highly acculturated” because of their work history, proficiency in English, or years spent in the United States. But greater adaptation does not necessarily mean greater social inclusion [7]. Hagos and Hamilton, for example, show that the relationship between time spent in the US and health differs considerably by race and ethnicity. Black immigrants had particularly poor hypertension profiles, while Black and Hispanic immigrants had particularly poor obesity profiles [7]. Their findings suggest that acculturation alone cannot adequately explain the different health trajectories experienced by immigrant groups [7]. To me, this exposes an important weakness in the assumption that acculturation eventually leads to integration. An immigrant can speak English, work, understand the dominant culture, and spend decades in a country while still experiencing racial or social exclusion. Adaptation and acceptance are not the same thing. If someone appears “highly acculturated” according to the measures researchers use but remains socially marginalised, the question should not only be why that person has failed to integrate. We should also ask what barriers remain after they have done everything to meet conventional measures of acculturation.

This is ultimately why terminology in immigrant health research matters. Research language does more than describe a problem. It helps determine where we look for its cause. If worsening health is framed primarily as an effect of acculturation, we ask what has changed about immigrants. If we also examine discrimination, food insecurity, economic exclusion, and institutional expectations, we begin asking what immigrants have been exposed to. Those are not the same questions, and they can lead to very different interpretations of the same health outcomes. None of this means that acculturation is useless or that cultural change has no effect on health. Acculturation can influence identity, relationships, behaviours, and wellbeing, and it remains an important concept to study. The problem arises when it becomes an umbrella explanation for outcomes that may have several competing explanations. Researchers should be clearer about what they mean by acculturation, distinguish it from assimilation, and recognise the limitations of using variables such as language proficiency and time in the new country as substitutes for a much more complicated process.

Instead of seeing poor health simply as a consequence of cultural change, we should explore how social processes make people more vulnerable and how the language of acculturation can sometimes help us ignore that. Before asking how well immigrants have adapted to society, perhaps we should also ask how well society has adapted to them.