Mind-body interventions (MBIs) like yoga and meditation are practiced by millions of people worldwide, who swear by their mental and physical benefit. Now, a medical review seems to indicate that these MBIs might have deeper effects than previously thought, even down to a molecular level.

The research, published in Frontiers in Immunology, focused on 18 studies with a combined total of 846 participants over 11 years. It found that people who practiced MBIs had a lower presence of nuclear factor kappa B, a molecule that regulates how genes are expressed, in particular one that is related to the production of cytokines.

Cytokines are usually produced during high-stress periods, such as in “fight-or-flight” situations, but it can also be damaging if it remains at a high level for a long time. An overabundance of this protein has been linked to a higher risk of diseases like cancer, mental health conditions, and even accelerated aging.

This shouldn’t be interpreted as "yoga stops cancer" or "meditation cures depression". Not only is that not how it works, but it’s not what the study suggests. What this research indicates is that people who practice mindfulness activities might be in a better position to deal with the molecular consequences of stress. 

Stress activates the sympathetic nervous system (SNS), and researchers suppose the connection between MBIs and lowered nuclear factor kappa B has to do with the SNS. This is definitely intriguing, but it’s still a preliminary result. The researchers themselves state that more research is required and that the small number of studies they looked at can’t be used to draw definite conclusions.

"More needs to be done to understand these effects in greater depth, for example how they compare with other healthy interventions like exercise or nutrition," lead investigator Ivana Buric, from the Brain, Belief and Behaviour Lab in Coventry University's Centre for Psychology, Behaviour and Achievement, said in a statement. "But this is an important foundation to build on to help future researchers explore the benefits of increasingly popular mind-body activities."

There are many different approaches to mind-body interventions. Mindfulness, yoga, Tai Chi, Qigong, relaxation response, breathing regulation, and meditations are all forms of MBIs. For a future study, it would be interesting to see if these MBIs have different effects on the body.