NIH-supported implementation science and nutrition research: a portfolio review of the past decade.

Objective: This portfolio analysis aims to describe the scope of NIH-funded extramural research grants at the intersection of nutrition research and implementation science (IS) from 2011 to 2022 and to offer insights into future research opportunities relevant to the Strategic Plan for NIH Nutrition Research 2020-2030. Methods: A portfolio analysis of funded grants using NIH reporting systems was conducted to identify nutrition research and IS awarded between fiscal years 2011 and 2022. The authors screened the titles and abstracts for inclusion criteria: research and career development awards involved a nutrition and/or dietary intervention and measured a stated implementation outcome or used an IS theory, model, or framework. Results: In total, 33 NIH-funded awards met the inclusion criteria. Almost half of the awards (48.5%) were investigator-initiated research projects compared to research career awards and cooperative agreements. While studies were predominantly conducted in the United States, 15.2% were conducted in low- and middle-income countries in Africa, Latin America, and Asia. Adults aged 19-64 years and children aged 2-11 years represented most of the study populations (45.5 and 15.2%, respectively). Studies provided nutrition/dietary guidelines and created culturally tailored interventions, which were then adapted in collaboration with community partners in schools, hospitals, and religious settings. The most cited IS outcomes were feasibility, costs, adoption, and acceptability. Sixteen awards (48.5%) used an IS theory, model, or framework to guide their work. Discussion: The findings show the breadth of NIH-funded nutrition and implementation research and highlight potential research opportunities.