Perspective: Biomarkers of Aging in Human Nutrition Research-A Focus on Applications, Challenges, and Opportunities.

Predictive algorithm-based biomarkers of aging (BoA), such as aging clocks, are increasingly applied within human nutrition research. Despite great promise of these BoA, validation efforts and guidelines for implementation are lagging behind the vast and growing number of available biomarkers, complicating their use and introducing variance across studies. Therefore, in the current perspective paper, we provide practical insights and an initial set of recommendations for consistent future implementation of BoA within nutrition research based on current knowledge, both on a general level and within different research scenarios. We critically reflect on existing observational and experimental nutrition research, and outline the potential application of BoA in identifying at-risk groups, exploring heterogeneity underlying aging and nutritional effects, and personalized approaches. This work aims to support nutritional researchers in making informed decisions on contextually appropriate biomarkers and provides directions for future nutritional research involving BoA, because, despite much needed advancements, we consider BoA exciting and promising tools in nutrition research.