Food and Nutrition: Exposures – Healthy Cities Toolkit

Description

Food is a substance composed essentially of proteins, carbohydrates, fats, and other nutrients required by living organisms to sustain life and vital processes, produce energy, and support growth [Encyclopedia Britannica]. An accumulating body of evidence has shown that the intake of certain types of food or specific dietary practices enhances health and reduces the risk of contracting common non-communicable diseases (NCDs) [Cena and Calder, 2020].

Impact

Environmental and social factors can influence food store selection and purchasing behaviour. There is a paucity of research examining the association between food exposure and nutritional status in low- and middle-income countries (LMICs). Lower socio-economic status (LES) is associated with less healthy food behaviour and poorer nutritional outcomes.

Results

Six reviews comprising over 180 primary studies examined the impact of environmental exposure on nutritional status – five of these reviews were systematic in design, while one was a narrative design.

One systematic review assessed the social determinants of health on child-adolescent immigration and its effect on nutritional status [Cheikh Moussa 2014]. The second review examined the impact of environmental exposure on nutrition outcomes [Turner 2020]. A third scoping systematic review (n=30) of the influence of local food environments on food behaviours [Pitt 2017], and a fourth investigated the association between urban food systems and health outcomes [Vieira 2018]. The fifth systematic review examined the impact of urban poverty on nutritional outcomes [Vilar-Compte 2021].

Nutrition

Four reviews explored the relationship between environmental exposure and nutritional outcomes.

Lack of access to healthy food may be associated with low socio-economic status [Vieira 2018]
Evidence regarding the relationship between food environment exposure and nutrition status in LMICs is inconclusive [Turner 2020]
Individuals with LES in urban areas have an increased risk of consuming unhealthy and energy-dense foods associated with a higher prevalence of overweight and obesity [Vilar-Compte 2021]
Urban poverty was associated with an increased risk of chronic undernutrition, leading to higher obesity prevalence in future stages of life [Vilar-Compte 2021]
Earlier immigrant generations (Hispanics) were characterised by the food culture and the linguistic isolation that reduced the risk of being overweight or obese [Cheikh Moussa 2014]
The prevalence of overweight and later obesity was higher in Hispanic individuals compared to the native population of the studied country (n=4 studies) [Cheikh Moussa 2014]

One narrative review (n=15 articles) examined the impact of a healthy food environment on the risk of obesity [Lebel 2012]. The authors reported that a higher local density of BMI-healthy food outlets was associated with a lower prevalence of obesity; higher BMI was associated with the presence of convenience stores around the children’s homes. Visits to fast food outlets were associated with higher BMI in females and white males and increased odds of obesity in older adults.

Food Promotion

Three reviews explored the factors that influenced food choices.

Availability, accessibility and affordability were frequently identified as key determinants of store choice and purchasing behaviours that often resulted in less healthy food choices [Pitt 2017]
Food availability and quality within stores, and food store characteristics also greatly influenced in-store purchases [Pitt 2017]
Media and advertising each influence food purchasing behaviours [Pitt 2017]
Several studies in Australia, UK and US showed that people living in lower-income neighbourhoods have fewer healthy food choices [Lebel 2012]

Strength of the evidence

Four reviews reported on the quality of primary studies. In Cheikh Moussa 2014, the overall quality was good or excellent in 17/18 of included studies. In Pitt 2017, only 4/30 of the included articles fulfilled all the quality criteria. Turner 2020 reported that the overall quality of evidence was low. In Vilar-Compte 2021, the overall quality of qualitative studies (n=13) was high, while the quality across the quantitative studies (n=55) was variable.

Resource implications

One review reported that local food production and the growth of food in urban areas develop a stronger local economy [Vieira 2018]; however, this required planning strategies and infrastructure for it to be expanded. The most frequently reported components relating to economic impact were: nurturing a vibrant and diverse local food economy, diversifying of food markets and retail, and diversifying food production systems.

Recommendations

Policy and behavioural change interventions should involve a socio-ecological approach beyond the exploration of the environmental determinants.
Future studies should investigate contextual influences within food environments as well as individual and household socio-economic characteristics that contribute to the varied use of and views towards local food environments.
Future research should seek to harmonise theoretical concepts with empirical research.
Rigorous mixed-methods designs should be implemented to provide comprehensive assessments of external and personal food environment domains and dimensions.
Food environment research should address low-income and lower-middle-income countries as a priority.
The potential of alternative food networks to enhance the components expected of sustainable and resilient urban food systems (UFS) should be explored.
Pathways through which public policy and governance can adopt to deliver relevant nutritional component outcomes should be investigated.
Further research should be more explicit with respect to comparison groups (e.g., urban or rural populations in very small, small, medium size cities and metropolis)

Related Resources

Cena 2020 “Defining a Healthy Diet: Evidence for The Role of Contemporary Dietary Patterns in Health and Disease.” Nutrients vol. 12,2 334. 27 Jan. 2020, doi:10.3390/nu12020334

References to Reviews

Cheikh Moussa 2014. “The social determinants of health of the child-adolescent immigration and its influence on the nutritional status: systematic review.” Nutr Hosp. 2014 Nov 1;30(5):1008-19. doi: 10.3305/nh.2014.30.5.7732. PMID: 25365003.

Pitt 2017 “Exploring the influence of local food environments on food behaviours: a systematic review of qualitative literature.” Public health nutrition vol. 20,13 (2017): 2393-2405. doi:10.1017/S1368980017001069

Lebel 2012. “Lifestyles and consumption in cities and the links with health and well-being: the case of obesity.” Curr Opin Environ Sustain. Volume 4, Issue 4, October 2012, Pages 405-413.

Turner 2020. “Food Environment Research in Low- and Middle-Income Countries: A Systematic Scoping Review.” Advances in nutrition (Bethesda, Md.) vol. 11,2 (2020): 387-397. doi:10.1093/advances/nmz031

Vieira 2018. “Unpacking components of sustainable and resilient urban food systems”. J Clean Prod. Volume 200, 1 November 2018, Pages 318-330.

Vilar-Compte 2021. “Urban poverty and nutrition challenges associated with accessibility to a healthy diet: a global systematic literature review.” International journal for equity in health vol. 20,1 40. 20 Jan. 2021, doi:10.1186/s12939-020-01330-0