1Background

The need for improved dietary behaviour

The composition of habitual diets is associated with adverse or protective effects on health.^1–3 Specifically, diets high in saturated fats and sodium have been found to increase the risk of cardiovascular diseases (CVDs), whereas those high in fruit and vegetables and low in saturated fats have been linked with reductions in a range of diseases including some cancers, CVD and hypertension.^4–7 The World Health Organization reports that the consumption of up to 600 g per day of fruit and vegetables could reduce the total worldwide burden of disease by 1.8%, and reduce the burden of ischaemic heart disease and ischaemic stroke by 31% and 19%, respectively.⁸ In the UK, the consumption of fruit, vegetables, dietary fibre, iron (pre-menopausal women only) and calcium are well below recommendations, whereas intakes of saturated fats and sodium exceed recommendations in large sections of the population.⁹ Consequently, UK public health policy strongly advocates dietary change for the improvement of population health and emphasises the importance of individual empowerment to improve health,^7,10 thereby shifting the focus of the NHS from treatment to prevention of illness.^11,12

Adaptive e-learning via interactive computerised interventions

A new and evolving area in the promotion of dietary behavioural change is ‘e-learning’, the use of interactive electronic media to facilitate teaching and learning on a range of issues including health. E-learning has grown out of recent developments in information and communication technology, such as the internet, interactive computer programs, interactive television and mobile telephones.^13–17 These technologies are rapidly becoming more accessible to the general population (e.g. an estimated 70% of the UK population has access to the internet and this percentage is likely to continue to grow¹⁸).

The high level of accessibility, combined with emerging advances in computer processing power, data transmission and data storage, makes interactive e-learning a potentially powerful and cost-effective medium for improving dietary behaviour.^19–21 It also has a number of potential advantages compared with traditional approaches for promotion of dietary behaviour change, such as the possibility of tailoring to individual circumstances,²² translating complex information through video, graphics and audio systems,²³ and potential cost savings on face-to-face interventions involving health-care practitioners. The evidence that individualised, tailored e-learning approaches are more effective than traditional non-tailored interventions²⁴ has given them a promising lead in health education.^25–27

E-learning interventions may be classified into three ‘generations’, first-generation interventions use computers to tailor printed materials; second-generation interventions use interactive technology delivered on computers; and third-generation interventions use portable devices, such as mobile telephones, for more immediate interaction and feedback.²⁸ An exploration of the properties of different e-learning interventions is required in order to determine the possible effective components (where a component comprises both ‘content’ and ‘delivery’; Figure 1).

FIGURE 1

Conceptual diagram of an intervention (reproduced from Edwards et al.).

Figure 2 illustrates that dietary behaviours are likely to be heavily influenced by macro factors at the environmental level (e.g. access to shops selling fruit and vegetables at affordable prices); organisational level (e.g. energy-dense ‘junk’ food vending machines in schools or workplaces); population level (e.g. low income and unemployment); and sociocultural level (e.g. interpersonal influences, such as where one person is responsible for meals eaten by others in a household). These wider determinants of dietary behaviour are unlikely to be changed by individually targeted interventions such as e-learning. Individual-level factors such as self-efficacy, knowledge and intention may be subject to change by e-learning. An exploration of the potential cognitive and emotional mediators of individual dietary behaviour change is required in order to elicit potential mechanisms of action.

FIGURE 2

Conceptual elements of behaviour and behaviour change (reproduced from Edwards et al.).

There is a risk that e-health and the use of new technologies in health care might widen health inequalities on either side of the ‘digital divide’. Experience suggests that there are two dimensions to the digital divide and its impact on health inequalities: access (to physical hardware and software) and accessibility (or the ability of people with differing literacy/health literacy/IT literacy to use or apply information and support supplied through e-learning). It has been shown that it is possible to deliver e-health interventions specifically designed for people with low literacy skills (e.g. Hispanics in southern USA,³⁰ homeless drug users³¹ and single teenage mothers³²). What remains less clear is the extent to which people with low literacy skills will feel comfortable using e-learning devices or will be able to act on information or advice provided through these media.

Interactive e-learning programs to promote positive dietary behavioural changes may have the potential to benefit population health. However, before e-learning can be considered as a dietary behaviour change intervention, the effective components and mechanisms of action of e-learning programs should be explored, and their cost-effectiveness established in different contexts.

Previous reviews

Three systematic reviews have examined the effectiveness of e-learning for dietary behaviour change. The first³³ was restricted to first-generation interventions for dietary change and did not include any web- or internet-based interventions. The second³⁴ examined a broad range of second-generation interactive interventions for dietary behaviour change. Both of these reviews reported studies published prior to 2006 that were carried out in a variety of settings. The third review²⁸ was more recent, reviewing second- and third-generation interventions trialled up to 2008, but only in primary prevention in adults (no participants with diagnosed disease). All reviews were restricted to publications in the English language and limited their searches to relatively few databases, increasing the potential for publication bias. The conclusions drawn from these systematic reviews were that e-learning shows some promise for dietary behavioural change, although the findings were mixed. Interstudy heterogeneity with respect to study design, participants, measures and outcomes precluded meta-analysis to estimate pooled intervention effects. Moreover, the cost-effectiveness of e-learning was not evaluated in any review, nor was there an attempt to identify potential mechanisms of action.