Calorie-Restriction Benefits, No Diet Required: A Molecular Discovery
A team led by Professor Vishwa Deep Dixit at Yale School of Medicine has identified a molecular mechanism that reproduces the rejuvenating effects of calorie restriction without requiring strict diets. The findings, published in Nature Aging, show that levels of complement 3 (C3), a protein with a central role in chronic inflammation, fell in all 42 participants of the CALERIE trial—regardless of how much weight they lost. Those participants cut their calorie intake by 11–14% and shed roughly 8 kilograms on average. Calorie restriction has long been studied for its anti-aging effects, but adhering to such diets over time is difficult for many people.
Analyzing more than 7,000 proteins, the researchers found a marked drop in C3 among those on restricted diets. This decline was not tied to changes in body mass index or the amount of fat lost. The main source of C3's age-related increase appears to be macrophages residing in white visceral adipose tissue.
The Yale team is also exploring whether existing drugs could restore C3 balance in humans. In mice, a compound that inhibits C3 activity significantly reduced age-related inflammation even though the animals' diets remained unchanged. The researchers caution that extreme calorie restriction can harm reproductive function, slow growth, and leave the body vulnerable to infections—underscoring the need for safer alternatives.
As part of the study, the investigators used single-cell RNA sequencing to analyze blood plasma samples in detail. The CALERIE project represents a key step toward understanding aging mechanisms and how they might be corrected. The results could guide future research on aging and health, and potentially reshape strategies for preventing and treating age-related diseases if C3-regulating drugs prove effective in people.
Understanding the complex mechanisms behind aging is crucial, especially as our bodies naturally adapt over time. For instance, research has shown that older adults often experience a decline in mobility, which can be linked to the body's inherent safety strategies. To explore this connection further, read about why older individuals tend to walk more slowly and tire more quickly.