Induction of salivary nerve growth factor by Yogic breathing: a randomized controlled trial.

The current study presents a randomized controlled trial in induction of salivary nerve growth factor by Yogic breathing (YB). A total of 20 volunteers (male and female), aged 18 years and above, were recruited from Charleston Metro area following written informed consent. In a single, 20-minute one-on-one session with the Yoga instructor, the Attentional Control (AC) group quietly read a scientific text of their choice for 20 minutes whereas the YB group performed 10 minutes of Om chanting followed by 10 minutes of Thirumoolar Pranayamam. A mixed model with repeated measures was used to estimate the between-group differences over time. Both duplicate post measures were used (as the repeated measures), and the model was adjusted for the baseline (average of the two duplicate pre-NGF values). The authors also allowed for the variances within the AC and YB groups to be different. The results were further evaluated by Western blotting which showed that 60% of the samples showed a marked increase in Nerve growth factor (NGF) level only in the YB group but not in the AC group. These results indicate that NGF could be stimulated in saliva by acute YB practice, and that further study may be warranted. It is to be emphasized here that this pilot study is the first ever attempt to stimulate endogenous NGF expression by non-invasive methods. Findings could lead to future studies on using salivary neuromodulators and biomarkers as outcome measures of Yoga interventions.