Meditation Improves Endothelial Function in Metabolic Syndrome
March 18, 2011 (San Antonio, Texas) — Meditation may help improve endothelial function in patients with metabolic syndrome, potentially reducing cardiovascular risk, new research suggests.
Presented here at the American Psychosomatic Society 69th Annual Scientific Meeting, a randomized trial in a group of African American patients with metabolic syndrome showed significant improvement in endothelial function in those randomly assigned to a year-long meditation program compared with their counterparts who underwent a program of health education alone.
"We found there was a significant difference between the consciously resting meditation group and the health education group in the flow-mediated dilation, which measures endothelial function," principal investigator Kofi Kondwani, PhD, National Center for Primary Care, Morehouse School of Medicine, Atlanta, Georgia, told Medscape Medical News.Dr. Kofi Kondwani
A risk factor for coronary heart disease, the clinical manifestations of metabolic syndrome include hypertension, hyperglycemia, high triglycerides, reduced high-density lipoprotein, and abdominal obesity. A diagnosis of metabolic syndrome is contingent on an individual having 3 or more of these risk factors.
According to the investigators, the etiology of metabolic syndrome is complex, but psychological stress appears to play a role, possibly through overactivation of stress hormones. They also note that endothelial dysfunction, which is also influenced by stress, is a major consequence of metabolic syndrome.
In addition, metabolic syndrome is a major health concern in the African American population — particularly among African American women — and is increasing in prevalence, paralleling the US obesity epidemic.
Particular Problem for African Americans
According to Dr. Kondwani, it has been shown that meditation can be effective in reducing psychological stress and improving some cardiovascular risk factors. However, he added, whether it can improve endothelial function in the setting of metabolic syndrome is unknown.
He noted that although metabolic syndrome and cardiovascular disease are important health issues in general, the major health disparities that exist in the African American population make it a particular concern in this population.
"If we could find some simple, easy, cost-effective approach to reduce some of these risk factors — whether it is blood pressure or endothelial function — that could be adopted in the community on a large scale we may be able to have a positive impact on the health of African Americans," he said.
A joint initiative between Morehouse Medical School and Emory University, the study randomly assigned 65 African American patients age 30 to 65 to undergo consciously resting meditation (CRM) (n = 32), a 12-month meditation program developed by Dr. Kondwani, or a 12-month health education program (n = 33). At study outset there were no significant differences in demographic characteristics or cardiovascular risk factors between the 2 groups.
The CRM group received three 90-minute sessions of initial instructor-led training. They returned once a week for the following 3 weeks, then once every 2 weeks for 2 months, and finally once per month for the remainder of the study. In the interim they were assigned “home rest” assignments that involved meditating for 15 to 20 minutes twice a day.
Improvements in Blood Pressure, Weight, Triglycerides
The study’s primary outcome measure was endothelial function assessed by brachial artery flow-mediated dilation (FMD) at baseline and 6 and 12 months. A secondary outcome was arterial stiffness, measured by pulse-wave velocity.
Trend tests were performed to assess changes in outcome measures and metabolic syndrome factors across the 3 study time points. The investigators found that FMD significantly improved from baseline in the CRM group (2.10 ± 0.79; P = .009) but that improvement was smaller in the health education group (1.36 ± 0.80; P = .09). Dr. Kondwani said there was no difference in arterial stiffness in the groups.
The researchers also found favorable and statistically significant trends in 3 metabolic syndrome risk factors in the CRM group but not in the health education group: diastolic blood pressure (change, -6.24 ± 2.75 mm Hg; P = .03), weight (-2.52 ± 1.16 kg; P = .03), and triglyceride levels (-32 ± 15 mg/dL; P = .04).
Dr. Kondwani also pointed out that certain psychological factors, including some measures of depression, significantly improved in both study groups. This indicates that “that just because an intervention has an impact on patients’ psychological well-being doesn’t necessarily mean it is going to change their physiology.”
These findings, he added, suggest that physicians should not hesitate to encourage their patients to learn meditation. “It will not hurt and invariably it will help. They also shouldn’t get hung up on the type of meditation. It’s highly likely that even if patients weren’t trained in meditative practice but just sat quietly for 20 minutes twice a day there would be benefit, “said Dr. Kondwani.
Dr. Kondwani said that his group hopes to replicate the study’s findings in a larger trial with 150 participants in each arm.
"Wonderful" Form of Stress Management
Commenting on the study for Medscape Medical News, Lorenzo Cohen, PhD, a professor in the Department of Behavioral Science and director of the Integrative Medicine Program at M.D. Anderson Cancer Center in Houston, Texas, said it is well known that psychological stress has a profound effect on many biological functions.
"In our work we know that stress can directly impact certain cancer-related biological systems. We believe it is very important to provide different forms of stress management to patients to help relieve the psychological stress they experience due to life-threatening illness and that one wonderful form of stress management is meditation," Dr. Cohen said in an interview.
He added that it was not surprising to him that meditation had a positive effect on endothelial function or other measures of metabolic syndrome.
"We know that metabolic syndrome is related to inflammatory processes and we know that stress can increase inflammatory processes. We also know of course that meditation decreases these processes so it would make sense that it has the potential to be a useful adjunct to the treatment of this syndrome," said Dr. Cohen.
Dr. Cohen noted that in recent years meditation has gained a great deal of acceptance by the medical community and patients alike and is widely accessible.
Ideally, he said, it is useful to have an instructor teach patients how to meditate in order to optimize practice. However, he added, the tools of the information age, including Web-based programs and audio materials, can also be “quite useful.”
He said in his experience there has been some resistance among patients because of a belief that meditation is associated with religion. However, he added, once they are informed that it is taught in a secular manner, this concern is assuaged.
American Psychosomatic Society (APS) 69th Annual Scientific Meeting: Abstract 1639. Presented March 10, 2011.