A 10-year study published in EMBO Reports indicates that obesity may leave a lasting biological imprint on the immune system, potentially maintaining elevated health risks even after weight loss. Researchers from the University of Birmingham, supported by the NIHR Biomedical Research Centre: Birmingham, found that helper T cells (CD4+ lymphocytes) can retain molecular signs of past obesity through a process called DNA methylation, where chemical tags attach to DNA inside immune cells. These changes may persist for 5-10 years following successful weight reduction.
The study suggests that this lingering “memory” of obesity in helper T cells could interfere with normal immune functions, such as the removal of cellular waste (autophagy) and the regulation of immune aging (immune senescence). According to the researchers, these enduring changes may help explain why individuals who lose weight can remain at increased risk for obesity-related diseases even after returning to a normal weight. The findings imply that short-term weight loss may not immediately reduce the risk of conditions associated with obesity, and sustained weight management over several years may be necessary to fully reverse the effects of obesity on T cells. The researchers also propose potential therapeutic opportunities, such as repurposing drugs like SGLT2 inhibitors, to expedite the fading of this “obesity memory.” Source