How does acupuncture work?
Here are current thoughts from the National Institutes of Health on
the manner by which acupuncture might produce beneficial health results.
Many studies in animals and humans have demonstrated that acupuncture
can cause multiple biological responses. These responses can occur
locally, i.e., at or close to the site of application, or at a distance,
mediated mainly by sensory neurons to many structures within the
central nervous system. This can lead to activation of pathways
affecting various physiological systems in the brain as well as in the
periphery. A focus of attention has been the role of endogenous opioids
in acupuncture analgesia. Considerable evidence supports the claim that
opioid peptides are released during acupuncture and that the analgesic
effects of acupuncture are at least partially explained by their
actions. That opioid antagonists such as naloxone reverse the analgesic
effects of acupuncture further strengthens this hypothesis. Stimulation
by acupuncture may also activate the hypothalamus and the
pituitary gland,
resulting in a broad spectrum of systemic effects. Alteration in the
secretion of neurotransmitters and neurohormones and changes in the
regulation of blood flow, both centrally and peripherally, have been
documented. There is also evidence that there are alterations in immune
functions produced by acupuncture. Which of these and other
physiological changes mediate clinical effects is at present unclear.
Despite considerable efforts to understand the anatomy and physiology of
the "acupuncture points," the definition and characterization of these
points remains controversial. Even more elusive is the scientific basis
of some of the key traditional Eastern medical concepts such as the
circulation of Qi, the meridian system, and other related theories,
which are difficult to reconcile with contemporary biomedical
information but continue to play an important role in the evaluation of
patients and the formulation of treatment in acupuncture.
Some of the biological effects of acupuncture have also been observed
when "sham" acupuncture points are stimulated, highlighting the
importance of defining appropriate control groups in assessing
biological changes purported to be due to acupuncture. Such findings
raise questions regarding the specificity of these biological changes.
In addition, similar biological alterations including the release of
endogenous opioids and changes in
blood pressure have been observed after painful stimuli, vigorous
exercise, and/or relaxation training; it is at present unclear to what extent acupuncture shares similar biological mechanisms.
It should be noted also that for any therapeutic intervention,
including acupuncture, the so-called "non-specific" effects account for a
substantial proportion of its effectiveness, and thus should not be
casually discounted. Many factors may profoundly determine therapeutic
outcome including the quality of the relationship between the clinician
and the patient, the degree of trust, the expectations of the patient,
the compatibility of the backgrounds and belief systems of the clinician
and the patient, as well as a myriad of factors that together define
the therapeutic milieu.
Although much remains unknown regarding the mechanism(s) that might
mediate the therapeutic effect of acupuncture, it is encouraging that a
number of significant acupuncture-related biological changes can be
identified and carefully delineated.
Further research in this direction not only is
important for elucidating the phenomena associated with acupuncture, but
also has the potential for exploring new pathways in human physiology
not previously examined in a systematic manner.
Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine
REFERENCE:
National Institutes of Health
