Neighbourhood food environments and diet

Within developed countries such as Australia, few individuals meet dietary recommendations for fruits and vegetables¹. Although unhealthy dietary behaviours have often been reported at a national-level, the prevalence of unhealthy eating is often greatest in neighbourhoods with the highest levels of socioeconomic disadvantage. It is often suggested that living in disadvantaged areas may reduce an individual’s opportunity to eat healthy through the neighbourhood food environment. In its simplest form, neighbourhood food environments operate through the ‘community nutrition environment’ which relates to the type and location of food stores in an area, and through the ‘consumer nutrition environment’ which relates to within-store factors such as product availability, quality, price, and opening hours². Therefore, if a disadvantaged neighbourhood does not support healthy eating through the consumer nutrition environment (i.e. if fresh produce, high-fibre and low-fat options are not readily available within stores in these neighbourhoods) or community nutrition environment (if the stores that sell these products are not accessible) then healthy eating becomes a more difficult choice for residents living in these areas.

An investigation was recently undertaken into whether dietary behaviours within Melbourne, Australia are patterned by neighbourhood-disadvantage and if so, whether features within the neighbourhood community and consumer nutrition environments explain these associations³. This analysis was based on 1,399 women from 45 neighbourhoods of varying levels of socioeconomic disadvantage. Although it is recognised that women’s diets are different to those of men, the focus on women is prudent because their diet and purchasing behaviour is often a strong predictor of household nutrition, especially children’s diet. Survey data on fruit, vegetable, and fast-food consumption was linked with data on food store locations (supermarket, greengrocer and fast-food store density and proximity) and within-store factors (in-store data on price and availability for supermarkets and greengrocers) obtained through objective audits. After controlling for individual-level demographic and socioeconomic factors, neighbourhood-disadvantage was associated with less vegetable consumption and more fast-food consumption, but not with fruit consumption. It was hypothesised that any associations between neighbourhood-disadvantage and diet may be explained by variations in the neighbourhood nutrition environments. Although the study found poorer diets among women living in disadvantaged neighbourhoods in Melbourne, the differences were not attributable to less supportive nutrition environments in these neighbourhoods. This is partly explained by the fact that not all environmental features indicated unhealthy diets would be more likely in disadvantaged neighbourhoods. For example, fruits and vegetables prices were lower in neighbourhoods with higher levels of disadvantage.

The existing international evidence regarding the independent influence of neighbourhood factors on the procurement of food through food store accessibility remains contradictory. Further investigations as to why this is so are warranted. Previously, researchers have suggested that health behaviours, such as the purchasing and consumption of healthy foods, are linked to three key determinants:

1. motivation (an individual’s belief and willingness);
   
2. ability (an individual’s skills and confidence);
   
3. opportunity (whether the environment provides opportunity to engage in healthy behaviours)⁴.

Thus, it remains common-sense that neighbourhood-level food access is likely to contribute to dietary behaviours. So why do studies continue to get null and inconsistent findings? One explanation is that to date, measures of access that do not accurately reflect a person’s true contextual exposure to the full range of food vendors throughout the course of their daily lives. To better understand environmental determinants of food purchasing behaviours that could be modified to Promote healthier eating, the next phase of research needs to move towards people-based measures of exposure whereby unique geographic exposure areas are used for each individual based on their daily travel behaviours.

To summarise, while features of the built environment are increasingly being recognised as potentially important determinants of health behaviours, evidence to date does not always overwhelmingly support this notion. A move towards individual-based measures of exposure is in line with previously calls for improved conceptual models related to environmental influences on health behaviours⁵.