Evaluation of a Produce Prescription Program for Patients With Diabetes: A Longitudinal Analysis of Glycemic Control

Food prescribing in Canada: evidence, critiques and opportunities

INTRODUCTION

There is growing interest in food prescriptions, which leverage health care settings to provide patients access to healthy foods through vouchers or food boxes. In this commentary, we draw on our experiences and interest in food prescribing to provide a summary of the current evidence on this intervention model and critically assess its limitations and opportunities.

RATIONALE

Food insecurity is an important determinant of health and is associated with compromised dietary adequacy, higher rates of chronic diseases, and higher health service utilization and costs. Aligning with recent discourse on social prescribing and "food is medicine" approaches, food prescribing can empower health care providers to link patients with supports to improve food access and limit barriers to healthy diets. Food prescribing has been shown to improve fruit and vegetable intake and household food insecurity, although impacts on health outcomes are inconclusive. Research on food prescribing in the Canadian context is limited and there is a need to establish evidence of effectiveness and best practices.

CONCLUSION

As food prescribing continues to gain traction in Canada, there is a need to assess the effectiveness, cost-efficiency, limitations and potential paternalism of this intervention model. Further, it is necessary to assess how food prescribing fits into broader social welfare systems that aim to address the underlying determinants of food insecurity.

Diet in Food Insecurity: A Mediator of Metabolic Health?

Objective

Food insecurity (FI) is associated with poor metabolic health. It is assumed that energy intake and diet quality underlie this association. We tested the hypothesis that dietary factors (quantity and quality) mediate the association of FI with excess weight, waist circumference and glycemic control [glycohemoglobin (A1C)].

Methods

A mediation analysis was performed on data from the National Health And Nutrition Examination Survey using FI as an independent variable; body mass index (BMI), waist circumference, and A1C as metabolic outcome variables and total energy intake, macronutrients, and diet quality measured by the Healthy Eating Index-2015 (HEI-2015) as potential mediators.

Results

Despite a greater prevalence of obesity in participants experiencing FI, daily reported energy intake was similar in food-secure and -insecure subjects. In adjusted analyses of the overall cohort, none of the examined dietary factors mediated associations between FI and metabolic outcomes. In race-stratified analyses, total sugar consumption was a partial mediator of BMI in non-Hispanic Whites, while diet quality measures (HEI-2015 total score and added sugar subscore) were partial mediators of waist circumference and BMI, respectively, for those in the "other" ethnic group.

Conclusion

Dietary factors are not the main factors underlying the association of FI with metabolic health. Future studies should investigate whether other social determinants of health commonly present in the context of FI play a role in this association.

"Food Is Medicine" Strategies for Nutrition Security and Cardiometabolic Health Equity: JACC State-of-the-Art Review

"Food Is Medicine" (FIM) represents a spectrum of food-based interventions integrated into health care for patients with specific health conditions and often social needs. Programs include medically tailored meals, groceries, and produce prescriptions, with varying levels of nutrition and culinary education. Supportive advances include expanded care pathways and payment models, e-screening for food and nutrition security, and curricular and accreditation requirements for medical nutrition education. Evidence supports positive effects of FIM on food insecurity, diet quality, glucose control, hypertension, body weight, disease self-management, self-perceived physical and mental health, and cost-effectiveness or cost savings. However, most studies to date are quasiexperimental or pre/post interventions; larger randomized trials are ongoing. New national and local programs and policies are rapidly accelerating FIM within health care. Remaining research gaps require rigorous, iterative evaluation. Successful incorporation of FIM into health care will require multiparty partnerships to assess, optimize, and scale these promising treatments to advance health and health equity.

Effect of an Intensive Food-as-Medicine Program on Health and Health Care Use: A Randomized Clinical Trial

Importance

Food-as-medicine programs are becoming increasingly common, and rigorous evidence is needed regarding their effects on health.

Objective

To test whether an intensive food-as-medicine program for patients with diabetes and food insecurity improves glycemic control and affects health care use.

Design, Setting, and Participants

This stratified randomized clinical trial using a wait list design was conducted from April 19, 2019, to September 16, 2022, with patients followed up for 1 year. Patients were randomly assigned to either participate in the program immediately (treatment group) or 6 months later (control group). The trial took place at 2 sites, 1 rural and 1 urban, of a large, integrated health system in the mid-Atlantic region of the US. Eligibility required a diagnosis of type 2 diabetes, a hemoglobin A1c (HbA1c) level of 8% or higher, food insecurity, and residence within the service area of the participating clinics.

Intervention

The comprehensive program provided healthy groceries for 10 meals per week for an entire household, plus dietitian consultations, nurse evaluations, health coaching, and diabetes education. The program duration was typically 1 year.

Main Outcomes and Measures

The primary outcome was HbA1c level at 6 months. Secondary outcomes included other biometric measures, health care use, and self-reported diet and healthy behaviors, at both 6 months and 12 months.

Results

Of 3712 patients assessed for eligibility, 3168 were contacted, 1064 were deemed eligible, 500 consented to participate and were randomized, and 465 (mean [SD] age, 54.6 [11.8] years; 255 [54.8%] female) completed the study. Of those patients, 349 (mean [SD] age, 55.4 [11.2] years; 187 [53.6%] female) had laboratory test results at 6 months after enrollment. Both the treatment (n = 170) and control (n = 179) groups experienced a substantial decline in HbA1c levels at 6 months, resulting in a nonsignificant, between-group adjusted mean difference in HbA1c levels of -0.10 (95% CI, -0.46 to 0.25; P = .57). Access to the program increased preventive health care, including more mean (SD) dietitian visits (2.7 [1.8] vs 0.6 [1.3] visits in the treatment and control groups, respectively), patients with active prescription drug orders for metformin (134 [58.26] vs 119 [50.64]) and glucagon-like peptide 1 medications (114 [49.56] vs 83 [35.32]), and participants reporting an improved diet from 1 year earlier (153 of 164 [93.3%] vs 132 of 171 [77.2%]).

Conclusions and Relevance

In this randomized clinical trial, an intensive food-as-medicine program increased engagement with preventive health care but did not improve glycemic control compared with usual care among adult participants. Programs targeted to individuals with elevated biomarkers require a control group to demonstrate effectiveness to account for improvements that occur without the intervention. Additional research is needed to design food-as-medicine programs that improve health.

Trial Registration

ClinicalTrials.gov Identifier: NCT03718832.

Food Is Medicine: A Presidential Advisory From the American Heart Association

Unhealthy diets are a major impediment to achieving a healthier population in the United States. Although there is a relatively clear sense of what constitutes a healthy diet, most of the US population does not eat healthy food at rates consistent with the recommended clinical guidelines. An abundance of barriers, including food and nutrition insecurity, how food is marketed and advertised, access to and affordability of healthy foods, and behavioral challenges such as a focus on immediate versus delayed gratification, stand in the way of healthier dietary patterns for many Americans. Food Is Medicine may be defined as the provision of healthy food resources to prevent, manage, or treat specific clinical conditions in coordination with the health care sector. Although the field has promise, relatively few studies have been conducted with designs that provide strong evidence of associations between Food Is Medicine interventions and health outcomes or health costs. Much work needs to be done to create a stronger body of evidence that convincingly demonstrates the effectiveness and cost-effectiveness of different types of Food Is Medicine interventions. An estimated 90% of the $4.3 trillion annual cost of health care in the United States is spent on medical care for chronic disease. For many of these diseases, diet is a major risk factor, so even modest improvements in diet could have a significant impact. This presidential advisory offers an overview of the state of the field of Food Is Medicine and a road map for a new research initiative that strategically approaches the outstanding questions in the field while prioritizing a human-centered design approach to achieve high rates of patient engagement and sustained behavior change. This will ideally happen in the context of broader efforts to use a health equity-centered approach to enhance the ways in which our food system and related policies support improvements in health.

The Impact of Providing Material Benefits to Improve Access to Food on Clinical Parameters, Dietary Intake, and Household Food Insecurity in People with Diabetes: A Systematic Review with Narrative Synthesis

The high cost of healthy foods makes maintaining a healthy dietary pattern challenging, particularly among people with diabetes who are experiencing food insecurity. The objectives of this study were to: 1) review evidence on the impact of providing material benefits (e.g., food coupons/vouchers, free food, or financial subsidies/incentives) to improve access to food on clinical parameters, dietary intake, and household food insecurity in people with diabetes, and 2) review relevant economic evidence. Six databases were searched from inception to March 2023 for longitudinal studies with quantitative outcomes. Twenty-one studies were included in the primary review and 2 in the economic analysis. Risk of bias was high in 20 studies and moderate in 1 study. The number of randomized controlled trials and nonrandomized studies reporting statistically significant improvement, alongside Grading of Recommendations Assessment, Development, and Evaluation (GRADE) certainty of the evidence was: HbA1c: 1/6 and 4/12 (very low), systolic blood pressure: 0/3 and 1/8 (very low), diastolic blood pressure: 0/3 and 1/7 (very low), BMI: 0/5 and 2/8 (very low), body weight: 0/0 and 1/3 (very low), hypoglycemia: 1/2 and 1/2 (very low), daily intake of fruits and vegetables: 1/1 and 1/3 (very low), daily intake of whole grains: 0/0 and 0/2 (very low), overall diet quality: 2/2 and 1/1 (low), and household food insecurity: 2/3 and 0/0 (very low). The 2 studies included in the economic analysis showed no difference in Medicare spending from Supplemental Nutrition Assistance Program participation and cost-savings from medically tailored meals in an economic simulation. Overall, providing material benefits to improve access to food for people with diabetes may improve household food insecurity, fruit and vegetable intake, and overall diet quality, but effects on clinical parameters and whole grain intake are unclear. The certainty of evidence was very low to low by GRADE. PROSPERO (CRD42021212951).

Health and Economic Impacts of Implementing Produce Prescription Programs for Diabetes in the United States: A Microsimulation Study

Background Produce prescription programs, providing free or discounted produce and nutrition education to patients with diet-related conditions within health care systems, have been shown to improve dietary quality and cardiometabolic risk factors. The potential impact of implementing produce prescription programs for patients with diabetes on long-term health gains, costs, and cost-effectiveness in the United States has not been established. Methods and Results We used a validated state-transition microsimulation model (Diabetes, Obesity, Cardiovascular Disease Microsimulation model), populated with national data of eligible individuals from the National Health and Nutrition Examination Survey 2013 to 2018, further incorporating estimated intervention effects and diet-disease effects from meta-analyses, and policy- and health-related costs from published literature. The model estimated that over a lifetime (mean=25 years), implementing produce prescriptions in 6.5 million US adults with both diabetes and food insecurity (lifetime treatment) would prevent 292 000 (95% uncertainty interval, 143 000-440 000) cardiovascular disease events, generate 260 000 (110000-411 000) quality-adjusted life-years, cost $44.3 billion in implementation costs, and save $39.6 billion ($20.5-58.6 billion) in health care costs and $4.8 billion ($1.84-$7.70 billion) in productivity costs. The program was highly cost effective from a health care perspective (incremental cost-effectiveness ratio: $18 100/quality-adjusted life-years) and cost saving from a societal perspective (net savings: $-0.05 billion). The intervention remained cost effective at shorter time horizons of 5 and 10 years. Results were similar in population subgroups by age, race or ethnicity, education, and baseline insurance status. Conclusions Our model suggests that implementing produce prescriptions among US adults with diabetes and food insecurity would generate substantial health gains and be highly cost effective.