Growing Healthy Hearts: a pilot randomized controlled trial of a digitally delivered gardening, cooking, and Dietary Approaches to Stop Hypertension (DASH) diet intervention for adults with cardiovascular risk factors

Background: Fruit and vegetable gardening (herein referred to as gardening) is positively associated with two behavioral risk factors for cardiovascular disease (CVD), diet and physical activity. Since gardeners often report enjoying the activity, an intervention that fosters enjoyment (i.e., intrinsic motivation) in those interested could be a promising health promotion strategy. This study assessed the feasibility of Growing Healthy Hearts, a multicomponent gardening, cooking, and the Dietary Approaches to Stop Hypertension (DASH) intervention for adults with CVD risk. Methods: Using a 2-arm, parallel-group, pilot randomized controlled trial design, we conducted a 24-week intervention with 10 videoconference sessions and a private Facebook group. Content targeted gardening and cooking skills, nutrition knowledge, intrinsic motivation, and social support. Participants (aged 20 +) were randomized to the intervention or a no treatment control if they had low fruit and vegetable intake (< 5 servings/day), low physical activity (< 150 min/week), and ≥ 1 CVD risk factor. Feasibility was defined as acceptability (mean score on a 5-point scale), recruitment rates, retention, and treatment adherence (completion of 10 gardening tasks). Linear mixed-effects models evaluated changes from baseline to 24 weeks in fruit and vegetable intake, cooking, intrinsic motivation, and steps/day. Results: Forty participants were randomized within 3 months (20/group). They had a mean age of 48 years (SD 12) and were primarily white (n = 29, 73%) or African American (n = 6, 15%), and female (n = 34, 85%). All feasibility targets were met. The majority (90%, n = 36) completed the 24-week follow-up. The mean acceptability score was 4.8 (SD 0.34) and treatment adherence was high with 94.7% (18/19) of intervention participants starting a garden and completing a mean of 9.5 out of 10 gardening tasks (SD 0.48). Comparing changes from baseline to follow-up, the intervention group had higher fruit and vegetable intake (+ 0.94 cups/day, 95% CI: [0.08, 1.79]), steps/day (+ 1,029/day, 95% CI: [567, 1493]), and intrinsic motivation (+ 1.0, 95% CI: [0.34, 1.66]). Conclusions: The intervention was feasible and exploratory analyses revealed improvements in fruit and vegetable intake, steps/day, and intrinsic motivation. The next step is to test the efficacy and sustainability of the intervention effects in a well-powered efficacy trial. Clinical trial registration: Registered on Clinicaltrials.gov (NCT05720611). Registered on January 13, 2023, https://clinicaltrials.gov/study/NCT05720611?term=nct05720611&rank=1.