NHANES Study Links Dietary and Serum Iron Levels to Biological Aging Acceleration

A cross-sectional study of 13,284 U.S. adults indicates that both iron deficiency and supplemental iron intake above 18 mg/day accelerate biological aging, defining an optimal serum iron range of 15.2 to 18.8 µmol/L.

Researchers analyzed NHANES data from 13,284 U.S. adults (aged 20 and older) across the 2007-2010 and 2015-2018 cohorts to examine the associations between iron exposure and biological age (BA) deviations (PA, GoldBA, and LightBA).

Higher dietary iron intake was associated with a younger biological age, with GoldBA decreasing by 0.09 per two-fold increase.

In contrast, supplemental iron intake exceeding 18 mg/day was associated with accelerated biological aging, yielding a GoldBA beta coefficient of 0.35.

Serum iron exhibited a U/J-shaped relationship with biological aging, establishing an optimal physiological range of 15.2 to 18.8 µmol/L.

The researchers also identified optimal ranges for total iron (15.7 to 37.3 mg/day) and dietary iron (at least 13.6 mg/day), with the optimal serum iron range widening in postmenopausal women and individuals with chronic diseases.

The study highlights that the impact of iron on biological aging is source-dependent, distinguishing the benefits of dietary iron from the potential acceleration of aging associated with high-dose supplementation.

By establishing clinical-biomarker-derived ranges (15.2 to 18.8 µmol/L for serum iron), the research moves beyond standard deficiency-avoidance thresholds toward longevity-optimized metabolic targets.

Subgroup differences in the optimal serum iron ranges emphasize the need for personalized, demographic-specific dietary and therapeutic guidelines to mitigate age-related physiological decline.

These findings may influence the consumer longevity market, shifting demand away from standard, high-dose iron supplements toward highly personalized and precise biological-age-informed nutritional regimens.

Providers of biological clocks and clinical diagnostics may increasingly incorporate specific iron panels (ferritin, serum iron, and dietary intake metrics) to refine their algorithmic recommendations for patients seeking to optimize their rate of aging.

Future prospective, longitudinal clinical trials are necessary to determine if maintaining serum iron within the 15.2 to 18.8 µmol/L range actively retards biological aging markers over multi-year periods.