Long-Term Health and Economic Impact of a Community-Based, Gene-Guided, Nutrition Program: The Sakado Folate Project in Japan

Background/Objectives: Precision nutrition informed by genetic profiling has been proposed to improve public health outcomes; however, long-term, community-based evidence remains limited. This study evaluated the long-term health and economic impacts of the Sakado Folate Project. Methods: Since 2006, residents participating in the Sakado Folate Project received gene-guided nutritional counseling focused on folate intake and related lifestyle factors. Target genes included methylenetetrahydrofolate reductase (MTHFR), angiotensinogen (AGT), adrenoreceptor B3 (ADRB3), and uncoupling protein 1 (UCP1); Δ5-fatty acid desaturase (FADS1) was incorporated later. Biochemical markers, genetic polymorphisms, and health indicators were monitored longitudinally. Population-level health outcomes and per-capita medical expenditure data were compared with regional and national statistics. Results: In program participants (n = 888), folate status and biochemical indicators improved: 76.1% achieved the serum folate target (≥9.5 ng/mL) and 55.3% achieved the serum total homocysteine target (≤7 μmol/L). Healthier lifestyle behaviors were observed across 99,565 Sakado residents, with the city recording the highest proportion of individuals actively attempting lifestyle improvement (31%) of all districts in the region. Disease prevalence was lower in Sakado City than in Saitama Prefecture overall, at standardized prevalence ratios of 52% for stroke and 86% for cerebral infarction. Per-capita medical expenditure was also lower in Sakado City (¥337,800) than the national average (¥392,044) in 2021. Conclusions: Long-term implementation of a community-based, gene-guided nutritional intervention may improve population health outcomes and reduce healthcare expenditures. Integrating nutrigenomics into public health strategies alongside community education and food environment improvements may contribute to sustainable healthcare systems in aging societies.