A comprehensive health scoring system combining cognition, movement, sensory function, vitality, and psychological well-being successfully predicted disease risk and mortality across 501,615 UK Biobank participants over 15.5 years. The intrinsic capacity (IC) score declined non-linearly with age, with steeper declines in individuals who later developed diseases or died earlier. Each domain contributed uniquely to different health outcomes — cognition predicted dementia risk, sensory function forecasted hearing loss, and vitality correlated with cardiometabolic diseases. This multidomain approach represents a significant advancement in aging research, moving beyond single biomarkers to capture the complexity of functional decline. The identification of blood-based protein signatures, particularly for vitality through immune and metabolic pathways, opens possibilities for accessible monitoring tools. However, this preprint awaits peer review, and results may change. The study's observational design in a predominantly white British population limits causal inference and generalizability. While promising for clinical assessment of biological aging, practical implementation requires validation across diverse populations and healthcare settings before becoming a standard aging metric.