Calorie restriction improved a blood marker score in older adults
Calorie restriction improved the combined score by 2.2 points compared with no restriction; the difference narrowed to 1.2 points after accounting for weight change.
Limit: Exercise differences could affect the score; full adjustment was limited by overlap with clinical site
Edited by Boris Djordjevic · AgingResearch.News
In 829 older adults with overweight or obesity, researchers pooled data from seven randomized trials of calorie restriction. Participants averaged 67.5 years of age; 67.4% were women. The trials compared programs designed to reduce calorie intake with usual diets, health education or programs without calorie restriction. They lasted 20 weeks to 18 months. Several targeted 7–10% weight loss through dietary counseling or partial meal replacements.
The researchers combined six blood markers of inflammation, metabolism and kidney function into one score. Calorie restriction improved the score compared with no restriction. A mediation analysis, which estimated how much weight loss contributed to the effect, attributed 48.5% of the improvement to weight loss. The authors said this suggested that weight loss explained only part of the effect.
Why it matters
The authors see combined biomarker scores as potential tools for assessing responses to interventions that target biological aging.
Caveats
Weight loss itself was not randomly assigned, so estimating its contribution relied on assumptions about unmeasured factors. The outcome was a blood-marker score, not lifespan or disease, and the findings do not establish effects in younger or normal-weight people.
From the paper
- Participants
We pooled data from 829 participants selected from seven studies, with 494 (59.6%) assigned to CR and 335 (40.4%) to no-CR groups (Table 1).
- Who took part
This study is a mediation analysis of completed CR intervention trials in older adults using biospecimens from the Wake Forest Integrated Aging Studies Databank and Repository (IASDR).
- Ages
Participants were more likely to be female (67.4%) and white (82.0%) with mean age of 67.5 years.
- Duration
Intervention durations ranged from 6 to 18 months.
- Result
CR groups overall showed modest reduction in CRP with overall mean group difference of 1.09 mg/mL (95% CI 0.28, 1.89), IL-6 with overall mean group difference of −0.07 pg/mL (95% CI −1.09, 0.94), and CysC with overall mean group difference of −0.03 mg/L (95% CI −0.08, 0.02).
Results, Change in weight, BMI, and individual biomarkers by caloric restriction status
- Composite biomarker index
For the model using the quintile sum score as the outcome (Fig. 1A), CR was estimated to be associated with a −2.2 (95% CI −2.9 to −1.5) difference in the quintile score of change, with estimates for all studies being less than zero (see Supplemental Table 2).
Results, Caloric restriction as a predictor of change in biomarker index
- Composite biomarker index
The composite biomarker index (quintile sum score) also showed a notable indirect effect of −0.94 (95% CI −1.40 to −0.49).
- Body weight
Across all studies, randomization to CR was associated with a 6.7 kg (95% CI 5.9 to 7.5) difference in weight loss between groups (see Table 2).
Results, Both CR and change in weight as predictors of change in biomarker index
Quoted word for word from the full text on link.springer.com.
Caloric restriction is part of Bryan Johnson's Blueprint
The paper
Wake Forest University Health Sciences
GeroScience, Sep 12, 2026, Open access
