Sex and age differences in attitudes and intention to adopt personalised nutrition in a UK sample

The goal of personalised nutrition is to maintain current good heath, prevent dietary related health problems, or mitigate existing ones using nutritional and other relevant information about an individual to deliver specific healthy eating guidance and, potentially, nutritional products and services (Ordovas et al. 2018). Individually tailored nutrition advice delivered by personalised targeted messages has been shown to be more effective than generic, non-personalised nutrition advice in increasing healthy eating behaviour (Hoevenaars et al. 2020; Hu et al. 2020; Celis-Morales et al. 2017). At the same time, consumer interest in personalised nutrition has been increasing (Stewart-Knox et al. 2016. Poínhos et al. 2014; Stewart-Knox et al. 2013). This has driven an increase in the development of commercially offered services that can deliver evidence-based, personalised dietary plans that are tailored to individual lifestyle, phenotype, genotype, social circumstances and psychology (Abrahams 2020).

Previous research has pointed to sociodemographic differences in dietary health behaviour. Analysis of the UK National Diet and Nutrition Survey (N = 2083) (Roberts et al. 2018) indicated that intake of healthier foods (fish, fruit and vegetables) was more frequent among older people, those with a higher income and of higher socioeconomic status (SES). Surveys on factors related to dietary health promotion have consistently implied that males engage in less healthy eating practices than females (Maugeri et al. 2020; Barrea et al. 2019; Martinez-Lacoba et al. 2018; Hiller et al. 2017; Ashton et al. 2017; van Dillen et al. 2008) and that older people eat healthier diets than those who are younger (Kang et al. 2019; van Dillen et al. 2008). Less healthy dietary habits also tend to be more prevalent among the less educated (Kang et al. 2019; Tan et al. 2017), those with lower incomes (Tan et al. 2017) and those from a more deprived SES background (Maugeri et al. 2020; Martinez-Lacoba et al. 2018). Similarly, attitudes toward personalised nutrition and its future adoption are likely to vary according to sociodemographic characteristics and to follow the same trends. Studies on attitudes and adoption of personalised nutrition in relation to sociodemographic factors, however, are scarce. Surveys conducted in Hungary (N = 1000) (Szakaly et al. 2021), (N = 500) (Szakaly et al. 2016) and another in six EU countries (N = 5967) (Stewart-Knox et al. 2009) both suggested that attitudes toward personalised nutrition were more favourable in women than men. The Hungarian survey (Szakaly et al. 2016) also identified more favourable attitudes among those with a higher education level.

Dietary health promotion must consider the wider socioeconomic implications of associated technologies and potential for indirect negative consequences. Personalised nutrition services are currently (at the time of writing) almost exclusively provided by the commercial sector (Abrahams 2020). For the 30% of consumers who already use digital health devices (Abrahams 2020), adoption of personalised nutrition should be technologically feasible. That socioeconomically disadvantaged people are less likely to have internet broadband at home and to be digitally literate (Azzopardi-Muscat and Sørensen 2019; Weiss and Eikemo 2017) means they may be slower to adopt novel health technologies (Weiss et al. 2018). Food insecurity is also associated with more disadvantaged socioeconomic circumstances (Power et al. 2018). A possible unintended consequence of personal nutrition, therefore, is that it may not reach people living in disadvantaged circumstances (Stewart-Knox et al. 2016). If not made available and accessible to everyone in society, personalised nutrition will do little to address food insecurity and could serve to widen existing health inequalities.

This study considered differences in attitudes and intention toward personalised nutrition between sex, education level, income and occupational grouping as markers of socioeconomic disadvantage. A precondition for any gains is that we understand the degree to which intended recipients are receptive to personalised nutrition. The aim of this analysis was to identify societal groups within our study population who may be more or less receptive to and likely to engage with personalised nutrition initiatives. Given previous research indicating socioeconomic inequalities in healthy eating and access to health-enabling technologies, it is predicted that males, younger people and those with lower education level, with lower income and in manual occupations will hold less favourable attitudes toward personalised nutrition and will be less likely to intend to adopt it in the future.

Data on sex, age, income, education level and social class by occupation were collected online in the United Kingdom (UK; N = 1061) as part of the Food4Me survey. A detailed account of the survey methodology was published previously (Poínhos et al. 2014).

The attitude scale comprised the four general attitude items from Crites et al. (1994). Each item was measured on a 5-point semantic differential scale in response to ‘personalised nutrition is’: 1. very valuable – very worthless; 2. very pleasant – very unpleasant; 3. very interesting – very boring; and 4. very good – very bad. The attitude scale showed good internal consistency (α = .87). The question on intention to adopt personalised nutrition comprised three items (Ajzen 1991). The items were I intend to adopt personalised nutrition; I would consider adopting personalised nutrition; I am definitely going to adopt personalised nutrition. Each item was assessed on a 5-point Likert scale ranging from 1 = completely disagree to 5 = completely agree. The scale showed good internal consistency (α = .91).

Volunteers (N = 1061) were quota-sampled to be representative of the UK in terms of age (18–29 years = 23%; 30–39 years = 19.4%; 40–54 years = 36%; 55–65 years = 21.6%), sex (49% female) and education level (low = 49%; middle = 15.4%; high = 35.6%). Modal income was £11,001–22,000). Occupation was spread among the sample (Table 1).

Between-groups MANOVA indicated that females had significantly more positive attitudes to personalised nutrition than males (p < 0.001; η_p² = 0.012) and were significantly more likely than males to intend to adopt personalised nutrition (p = 0.003; η _p² = 0.009) (Table 1).

There was a significant effect of age on attitudes towards (p < 0.001; η_p² = 0.029) and intention to adopt (p < 0.001; η _p² = 0.033) personalised nutrition. Post hoc tests indicated that younger participants had more positive attitudes towards personalised nutrition and were more likely to adopt it (Table 1).

No significant effect of education level was observed on attitudes toward (p = 0.735) or intention to adopt (p = 0.392) personalised nutrition. Nor were there any significant effects of income group on attitudes toward (p = 0.692) or intention to adopt (p = 0.877) personalised nutrition. There were no significant differences between occupation groups in either attitude (p = 0.504 or intention (p = 0.553) to adopt personalised nutrition (Table 1).

This analysis sought to identify socioeconomic differences in attitudes and intention to adopt personalised nutrition. The results imply that males may be less receptive to personalised nutrition and less likely to take it up in the future. The finding that males held less favourable attitudes and were less likely than females to intend to adopt personalised nutrition agrees with previous survey research on healthy eating (Hiller et al. 2017) and on personalised nutrition (Szakaly et al. 2021; 2016; Stewart-Knox et al. 2009). This, along with results from the wider Food4Me survey (Fischer et al. 2016) indicating that males were less willing to pay for personalised nutrition than females, implies that personalised, nutritional genomic intervention should target men and women differently (Corella et al. 2019).

Attitudes and intention to adopt personalised nutrition were found to vary by age. Attitudes were more favourable among younger individuals than among those who were older. People in the youngest age group (18–29 years) were also more likely than any of the older age groups to intend to adopt personalised nutrition in the future. The positive attitude of younger people is particularly promising, since previous research has indicated that younger people eat less healthy diets than those who are older (Kang et al. 2019; Roberts et al. 2018; Martinez-Lacoba et al. 2018; Ashton et al. 2017; van Dillen et al. 2008) and encounter greater barriers in achieving a healthy diet (Adams et al. 2019). A possible reason that younger people are more favourable toward personalised nutrition, therefore, could be that it is perceived to hold potential to overcome barriers to healthy eating. The effect sizes were appropriate for age differences in attitude or intention, which implies we can have confidence in these findings.

Attitudes toward personalised nutrition and intention to adopt it did not differ between education level, household income or occupation grouping in this UK population sample. This was unexpected given previous research to suggest that dietary quality is related to education level (Kang et al. 2019; Tan et al. 2017) and income (Roberts et al. 2018; Tan et al. 2017). These null findings are also contrary to those of a previous survey conducted in Hungary indicating that attitudes toward personalised nutrition were more favourable among those with a higher education level (Szakaly et al. 2016).

This analysis suggests that males may be less likely than females to adopt personalised nutrition. Further in-depth enquiry is required to better understand sex differences in attitudes and intended adoption of dietary health technologies. That younger people held more positive attitudes and were more likely to intend to adopt personalised nutrition, bodes well for a future in which tech-enabled, personalised healthy eating services can be rolled out to all societal sectors as part of mainstream dietary health promotion. Harnessing technologies for individualised dietary health promotion and widening access to personalised nutrition to all sections of UK society could serve to narrow health inequalities, including those exacerbated by the COVID-19 pandemic.