Background 

The goal of this systematic review was to determine whether food access (i.e., the availability and affordability of foods) is associated with dietary intake, quality and variety. Food availability was measured in many ways for individuals, families and neighborhoods, including proximity to food outlets, density of food outlets, distance to the outlet closest to a residential location, mean distance traveled to food outlets where participants reported shopping and foods available in stores. Food availability was measured both objectively (e.g., food outlets per capita or within a certain radius of a participant’s home using geographic information systems) and subjectively (e.g., perceived availability of healthy vs. unhealthy food outlets and healthy foods in a store or neighborhood).

Conclusion Statement 

Emerging evidence suggests that the relationship between access to farmers’ markets and produce stands and dietary intake and quality is favorable. The body of evidence regarding access to other food outlets, such as supermarkets, grocery stores, convenience and corner stores, and dietary intake and quality is limited and inconsistent.

2015 DGAC Grade: Not assignable

Methods 

Literature searches were conducted using PubMed, Embase and Cochrane databases to identify studies that evaluated the association between food access and dietary outcomes. Studies that met the following criteria were included in the review: Randomized controlled trials (RCT), non-randomized controlled trials, prospective cohort studies, or cross-sectional studies; humans over the age of two years who were healthy or at elevated chronic disease risk; subjects from the United States; and published in English in peer-reviewed journals. The date range was January 2004 to January 2014. The intervention or exposure was food availability and accessibility compared to different levels of availability and accessibility. The outcomes were dietary intake, quality, behaviors and preferences.

Data from each included article were extracted and risk of bias was assessed. The evidence was qualitatively synthesized, a conclusion statement was developed and the strength of the evidence (grade) was assessed using pre-established criteria including evaluation of the quality and risk of bias, quantity, consistency, magnitude of effect and generalizability of available evidence.

Findings

• This NEL systematic review included 18 articles published since January 2004 that examined the relationship between food access and dietary outcomes. This literature included 15 cross-sectional studies, one longitudinal study and two controlled trials.
• The studies used multiple approaches to assess food access (i.e., the availability and affordability of foods) and dietary intake, quality and variety. The majority of studies measured food access by the density of food outlets within a specified distance from a participant’s residence and proximity to various food outlets. The majority of studies assessed dietary intake by focusing on fruit and vegetable consumption; diet quality and variety were predominantly determined by various diet indices.
  • Although food access was assessed across geographic, ethnic, racial and income groups, due to the wide variation in methods used to determine food access, making comparisons across studies was challenging. Despite this variability, a consistent relationship was identified between farmers’ markets and produce stands and diet.
  • Two studies found statistically significant, favorable associations between access to farmers’ markets and produce stands and dietary intake (assessed by fruit and vegetable consumption) and diet variety and quality [both assessed by the Healthy Eating Index (HEI)]
  • Due to the variability of studies and paucity of data, no consistent associations regarding dietary outcomes and access to other food outlets were evident.

Limitations

The ability to draw strong conclusions was limited by the following issues:

• Most studies were of weaker design (i.e., cross-sectional)
• The methodological differences across individual studies were significant
• The myriad retail outlets that sell food vary considerably.