ABSTRACT & COMMENTARY
Meditation at the Micro Level: Signs of Promise
By Howell Sasser, PhD
Associate, Performance Measurement, American College of Physicians, Philadelphia, PA
Dr. Sasser reports no financial relationships relevant to this field of study.
A study comparing experienced meditators and non-meditators found that the meditators had more favorable changes in some biochemical markers of stress-linked cell damage and inflammation. Those in both groups who responded more effectively to a stressful stimulus also showed somewhat better marker levels than those who responded less well.
Kaliman P, et al. Rapid changes in histone deacetylases and inflammatory gene expression in expert meditators. Psychoneuroendocrinology 2014;40:96-107.
- Meditators showed greater reductions than non-meditators in expression of 3 of 10 genes associated with chromatin modification.
- Meditators also showed greater reductions than non-meditators in expression of 2 of 6 proinflammatory genes.
An international research group conducted a small study of biochemical and gene markers associated with stress in convenience samples of experienced meditators (n = 19) and non-meditator controls (n = 21). For inclusion purposes, meditation experience meant at least 3 years of practice, a minimum of 30 minutes of daily meditation, and completion of at least three retreats of at least 5 days each.
For the study, the meditators completed a 1-day intensive program that drew extensively on the mindfulness-based stress reduction intervention developed by Jon Kabat-Zinn. The program included both sitting and walking meditation in guided and unguided forms, as well as brief inspirational talks and lunch (which was preceded by a short video on "mindful eating"). The control group participated in a program of the same duration that included reading, watching documentaries, playing computer games, and walking. Neither group had access to mobile telephones, the Internet, or other potential external distractions.
Participants also completed the Trier Social Stress Test, a challenge designed to induce stress through the use of public speaking and calculation tasks. The test was conducted twice for each participant, separated by an average of 12 weeks. The second measure for meditation group participants was taken immediately after the study day. Control group participants could be assessed at any time, subject to the 12-week interval requirement.
Blood samples were obtained from all participants at the beginning (8 a.m.) and end (4 p.m.) of the study day. Monocytes were fractioned out and used as the substrate for assessment of cytosolic proteins, histones (precursors of chromatin), and for genetic analysis (specifically, the following genes: HDAC1/2/3/5/9, SIRT1, SET7, G9a, LSD1, DNMT3A, RIPK2, CCR7, CXCR1, and genes controlling expression of COX2, IL-6, and TNF-α). Saliva samples were collected before and at intervals after each Trier test and used to assess salivary cortisol recovery.
From the beginning to end of the study day, the meditators showed more favorable changes than the controls (an average reduction of 17% vs an average increase of 3%) in the expression of some epigenetic markers of chromatin modification, a measure of stress at the cellular level. They also showed similar changes in a few proinflammatory genes. Participants in both groups with better cortisol recovery rates after the Trier test (i.e., those who responded more effectively to a stressful stimulus) showed lower levels of a few genetic markers. A summary of group-by-time differences is shown in Tables 1 and 2.
Table 1. Changes in Gene Markers for
Chromatin Modification, Measured on the Study Day (8 a.m. and 4 p.m), in Meditators and Non-Meditators |
Gene Name |
Greater Reduction Among Meditators |
HDAC1 |
|
HDAC2 |
* |
HDAC3 |
* |
HDAC5 |
|
HDAC9 |
* |
SIRT1 |
|
SET7 |
|
G9a |
|
LSD1 |
|
DNMT3A |
|
* P < 0.05
P ≈ 0.05 |
Table 2. Changes in Proinflammatory Genes, Measured on the Study Day (8 a.m. and 4 p.m.), in Meditators and Non-Meditators |
Gene Name |
Greater Reduction Among Meditators |
RIPK2 |
* |
COX2 |
* |
CCR7 |
|
CXCR1 |
|
IL-6 |
|
TNF-α |
|
* P < 0.05 |
COMMENTARY
These results are intriguing in that they appear to show an effect of a stress-modifying practice at the cellular level. However, they should be viewed as guides for further study rather than firm conclusions. The sample sizes (19 and 21) were quite small, and participants were recruited on a volunteer basis and not randomly assigned. It would be unwise to look at this group of meditators as typical of all practitioners, nor can we be sure that the controls were similar to the meditators in all respects except the practice of meditation.
The investigators themselves point out that there were two potential dimensions to this study’s comparisons — meditators vs non-meditators, and those taking part in daylong programs with different contents. They chose to focus on the first comparison, though it might have been equally valid — and interesting scientifically — to compare groups of experienced meditators who did and did not complete a day of meditation, or even groups of meditation-naïve participants.
This brings up the most important caution, uncertainty about temporal sequence. By beginning with a group of experienced meditators, the investigators were unable to say with certainty whether meditation practice preceded the observed cellular effects in those individuals. It seems equally plausible that meditation is only one expression of a more general capacity to manage stress in these individuals. A more powerful demonstration of the observed effects would have begun with a group of people known to handle stress in ways not typical of meditators ("Type A," aggressive, highly emotive), and observed the patterns of cellular change after a period of standardized meditation training. Nevertheless, this study adds to the fund of knowledge on this topic. Prior studies of similar outcomes have not included a non-meditation control group.1,2
For the present, it seems fair to suggest that patients who do not meditate at least give it a try and that those who already meditate be encouraged to continue to do so. There is enough evidence for the value of meditation to recommend it even as investigations into its precise mechanism(s) continue. However, meditation is not suited to every temperament or set of life circumstances. For most clinicians and most patients, it is best included as one part of a broader discussion of stress and approaches to managing it.
REFERENCES
- Bhasin MK, et al. Relaxation response induces temporal transcriptome changes in energy metabolism, insulin secretion and inflammatory pathways. PLoS ONE 2013;8:e62817.
- Dusek JA, et al. Genomic counter-stress changes induced by the relaxation response. PLoS ONE 2008;3:e2576.
