The role of nutrition-related clinical trials in informing dietary recommendations for health and treatment of diseases

Dietary guidance is based on a robust evidence base that includes high-quality clinical trials, of which some have been designed to establish causal relationships between dietary interventions and ASCVD risk reduction. However, the complexity associated with conducting these trials has resulted in criticism of nutrition and dietary recommendations because the strength and quality of evidence falls short of that for some pharmaceutical interventions. In this paper, we aim to promote greater awareness of the nutrition-related clinical trials that have been conducted showing ASCVD benefits and how this evidence has contributed to dietary recommendations. Compared to clinical trials of pharmaceutical agents, nutrition-related clinical trials have several unique considerations, including complexities of intervention design, challenges related to the blinding of participants to treatment, modest effect magnitudes, variability in baseline dietary exposures, absence of objective dietary adherence biomarkers, achieving sustained participant adherence, and the significant timeline for endpoint responses. Evidence-based dietary recommendations are made based on multiple lines of evidence including that from randomized controlled trials, epidemiological studies, as well as animal and in vitro studies. This research has provided foundational evidence for the role of diet in prevention, management, and treatment of ASCVD. Based on the clinical trials that have been conducted, a strong consensus has evolved regarding the key elements of healthy dietary patterns that decrease ASCVD risk. Going forward, implementation research is needed to identify effective translation approaches to increase adherence to evidence-based dietary recommendations.