Caloric Restriction, Energy Balance and Healthy Aging in Okinawans and Americans: Biomarker Differences in Septuagenarians.

Background: Caloric restriction (CR) is the only consistently reproducible non-genetic means of minimizing age-related diseases and increasing maximum lifespan in short-lived animals but few human studies exist.

Objective: Since elderly Okinawans exhibit several phenotypic features of CR including low BMI, low prevalence of chronic diseases, and exceptional longevity, we hypothesized that this phenotype may be reflected in candidate biomarkers of human aging.

Methods: We retrospectively estimated adult energy balance across the life course for septuagenarian birth cohorts (born ca 1915-1925) from Okinawa and the U.S. based on archived data. We then compared plasma DHEA, estrogen and testosterone in a sample of community dwelling members from these birth cohorts.

Results: Elderly Okinawans had much lower caloric intake than Americans and appeared mildly calorically restricted (10-15%) at younger ages relative to their estimated energy requirements. Okinawans also had significantly higher plasma DHEA, testosterone and estrogen levels as septuagenarians versus non-CR Americans of similar chronological age.

Conclusion: These cross-sectional data are consistent with the caloric restriction hypothesis in humans and support further longitudinal investigation into biomarkers of human aging and their potential modification by caloric restriction.