Effects of Yoga on Gene Expression: A Systematic Review of Randomised Controlled Trials.

Yoga, an integrative mind-body practice, is increasingly recognised for its ability to modulate gene expression, particularly that of genes associated with inflammation, stress, and aging. This systematic review, conducted per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, synthesises evidence from 11 randomised controlled trials (RCTs) from 2015 to 2024, involving over 700 adults. Studies were sourced from PubMed, Scopus, Web of Science, and the Cochrane Library to evaluate the molecular effects and clinical implications of yoga. Across these RCTs, yoga consistently downregulated pro-inflammatory genes - interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), and nuclear factor kappa B (NF-κB) - in five studies, and upregulated anti-inflammatory and immune-regulatory genes - transforming growth factor-beta (TGF-β), forkhead box P3 (FoxP3), soluble human leukocyte antigen G (sHLA-G), and IL-10 - in four studies. It also enhanced the expression of genes linked to deoxyribonucleic acid (DNA) repair (OGG1, or 8-oxoguanine DNA glycosylase), mitochondrial function (adenosine monophosphate-activated protein kinase (AMPK), and sirtuin 1 (SIRT-1)), and epigenetic regulation (e.g., reduced TNF methylation and increased microRNA-133B (miR-133B)). These molecular changes were associated with clinical benefits, including reduced disease activity in rheumatoid arthritis (RA), improved glycemic control in type 2 diabetes (T2D), and improved quality of life among breast cancer survivors. Despite these promising findings, the small sample sizes and short intervention durations limit statistical power and generalisability. Yoga shows potential as a complementary therapy for managing inflammation and age-related conditions, but larger, longer-term RCTs with standardised protocols are essential to substantiate its therapeutic value and elucidate its mechanisms.