DNA methylation, an epigenetic process that modifies gene expression and can alter physiological responses to psychological stress, is malleable and may be changed by psychobehavioral interventions such as mindfulness-based stress reduction, cognitive behavioral therapy, and yoga. This scoping review of 21 studies found that several reported differences in DNA methylation in response to such interventions across genes related to stress and inflammation, though many studies were inadequately powered. Studies varied widely in participant health status, intervention type and duration, biospecimens examined, and DNA analysis methods. Future research needs to address design limitations, evaluate biological importance, and link DNA methylation changes to physiological and psychological outcomes.
A 6-week mindfulness-based stress reduction program for breast cancer (MBSR(BC)) reduced the stress hormone cortisol and the inflammatory marker interleukin-6 (IL-6) immediately after class sessions in breast cancer survivors. Cortisol levels dropped from before to after class at both Week 1 and Week 6, and IL-6 decreased from before to after class at Week 6. However, no differences in cortisol or IL-6 were found between the MBSR(BC) group and a usual-care control group when comparing measurements taken at the start and end of the 6-week program. Small but significant links were seen between IL-6 levels and symptoms and quality of life across both groups. The results suggest MBSR(BC) can produce short-term reductions in these biological stress markers.