Abstract
Non-communicable diseases (NCDs) are on the rise worldwide, with low- and middle-income countries (LMICs) bearing more than three-quarters of global deaths from NCDs. Unhealthy diet is a major risk factor for NCDs and reducing the burden of NCDs hinges crucially on improving dietary choices and intake. This scoping review compiles evidence on the effectiveness of diet-focused behavioral interventions in LMICS.
Generated Summary
This scoping review examines the effectiveness of diet-focused behavioral interventions in Low- and Middle-income Countries (LMICs). The study employed a multi-step scoping review methodology, including a search of five electronic databases (PubMed, Web of Science, EMBASE, PsycINFO, and EconLit). The review focused on interventions aimed at influencing individual and household-level purchase and consumption of foods, excluding financial interventions and those focused on undernutrition. The initial search identified 5619 records, with 52 studies ultimately included in the analysis. The interventions investigated included education, messaging, multi-component approaches, and other methods. Outcomes assessed involved biological risk factors, nutritional intake, and nutritional knowledge. The search was performed between June 21, 2021, and July 14, 2021. The analysis utilized difference-in-differences (DiD) estimates and focused on statistically significant changes in outcomes.
Key Findings & Statistics
- Study Inclusion: The review included 52 papers published between 2007 and 2021.
- Geographic Distribution: Studies were conducted across various countries, with a concentration in India, Iran, China, and Mexico.
- Study Designs: The most frequent study designs included randomized controlled trials (RCTs, 31 studies), pre-post comparisons (13 studies), and longitudinal data analysis (6 studies).
- Participant Recruitment: The bulk of participants were recruited from schools and health centers/hospitals.
- Sample Size: The median number of participants in the studies was 320, with a range from 5 to 12,047.
- Intervention Types: The interventions analyzed included 10 educational interventions, 12 messaging programs, 26 multi-component interventions, and 4 other types (e.g., labeling efforts).
- Intervention Duration: Intervention duration varied from one day to 72 months, with typical and median durations of 10 and six months, respectively.
- BMI Outcomes: 16 studies assessed Body Mass Index (BMI) changes.
- Blood Pressure Outcomes: 10 studies examined blood pressure changes.
- Glucose Outcomes: 7 studies analyzed glucose changes.
- Cholesterol Outcomes: 5 studies measured cholesterol changes.
- HbA1c Outcomes: 3 studies assessed HbA1c changes.
- BMI Effects: Most studies showed a drop in BMI, with the strongest results in multi-component interventions, showing a reduction of 0.25 to 0.5 kg/m². The largest reduction in BMI was 2.66 (kg/m2) over 6 months from a multi-component intervention (Kose, 2021).
- Blood Pressure Effects: The strongest effect on blood pressure was a 9 mmHg reduction in systolic blood pressure from a comprehensive BP control program (Kim et al, 2020).
- Nutritional Intake Outcomes: 24 studies examined nutritional intake, showing varied results.
- Fruit and Vegetable Consumption: Increased consumption of fruits and vegetables by 25% or more was observed.
- Nutritional Knowledge Outcomes: 12 studies assessed knowledge changes, with 8 showing 25-50% improvements.
- Attrition: The mean attrition rate in the studies was 16%.
Other Important Findings
- Outcomes Measured: The studies primarily examined biological risk factors (BMI, blood pressure, glucose, cholesterol, HbA1c), nutritional intake (sugar, salt, fruits, vegetables, fats), and nutritional knowledge.
- Effect on Blood Pressure: Changes in blood pressure, cholesterol, HbA1c, and BMI were generally in the desired direction of change (lowering disease risk).
- Nutritional Knowledge: Nutritional knowledge increased 25-50% from baseline in 8 out of twelve studies.
Limitations Noted in the Document
- Scoping Review Limitations: The study’s scoping review approach, which encompassed multiple disciplines and journals, may have caused the omission of some relevant studies.
- Database Selection: The review was limited to English-language articles in five databases, potentially missing contextually specific research from some LMICs.
- Exclusion of Fiscal Policies: Studies examining fiscal policies (taxes and subsidies) were excluded.
- Heterogeneous Outcomes: The wide variety of measured outcomes made it challenging to compare interventions and draw definitive conclusions.
Conclusion
There is a pressing need for tailored interventions promoting healthy dietary behaviors in LMICs, given the increasing burden of non-communicable diseases (NCDs). The success of these interventions relies on making healthy food accessible, affordable, and the preferred choice. While there is diversity in LMICs, there is a general scarcity of behavioral interventions being implemented, with a few exceptions like China, Mexico, Iran, and India. Further research is needed to design and implement healthy dietary approaches, utilizing techniques such as nudges, better health education, and behavioral insights. Approaches should be tailored to local contexts, consider cultural factors, and address the influence of food and beverage industries. Innovation and sharing of best practices will establish norms and create a level playing field, enabling consumers to adopt healthier diets and mitigate NCD risks. The interventions that were most effective in improving health outcomes were multi-component interventions, but several studies found that messaging and education were also effective. The study suggests that real improvements in NCD risk might be achievable if the interventions are sustained beyond the average 6 months (median) of the studies in the review.