Decades of research has shown that limits on calorie intake by flies, worms, and mice can enhance life span in laboratory conditions. But whether such calorie restriction can do the same for humans remains unclear. Now a new study confirms the health benefits of moderate calorie restrictions in humans — and identifies a key protein that could be harnessed to extend health in humans.
Research has shown that limiting calorie intake can extend life span in flies, worms and mice, but whether it can do the same in humans is unclear.
A new study by Yale researchers has confirmed the health benefits of moderate calorie restrictions in humans and identifies a key protein that could be harnessed to extend health in humans.
The study used results from the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy clinical trial, which was the first controlled study of calorie restriction in healthy humans.
Researchers first established the calorie intake of over 200 study participants, and then asked some to reduce their intake by 14%, while others ate as usual, and analyzed the long-term effects of calorie restriction over the next two years. The thymus gland, which ages faster than other organs, was analyzed. The thymus gland of those with limited calorie intake had less fat and greater functional volume after two years of calorie restriction, meaning they were producing more T cells than they were at the start of the study.
This is exciting as there is little evidence of organs rejuvenating in humans. However, when researchers sequenced the genes in the immune cells that the thymus was producing, they found there were no changes in gene expression after two years of calorie restriction. Instead, it was found that the action was really in the tissue microenvironment, not the blood T cells.