I lie down on the table, sighing in grateful anticipation as my longtime acupuncturist, Jen Forrest Evans, goes to work. Some days, she gently pokes needles into my chronically tight lower back. Other days, she focuses on my pesky sinuses. Still other days - the best ones - the goal is a general tuneup of my qi (pronounced "chee"), the Chinese term for vital (and sometimes, not vital enough) energy.
This ancient Chinese technique of sticking needles into the skin to relieve pain, nausea and many other ills never fails to make me feel better - more mellow and energized.
I used to think this lovely state was mostly because of the placebo effect. But a growing body of evidence - brain scans, ultrasound and other techniques - now shows that acupuncture triggers direct, measurable effects on the body, including, perhaps, activation of precisely the regions of the brain that would be predicted by ancient Chinese theory.
This is potentially good news for millions of Americans now scrambling for pain relief in the wake of conflicting government recommendations on painkillers Vioxx and Celebrex.
At the University of California, Irvine, researchers have shown that when a needle is placed in a point on the side of the foot that Chinese theorists associate with vision, sure enough, the visual cortex in the brain "lights up" during fMRI, or functional magnetic resonance imaging scans, though the cause and effect are not totally clear.
Neuroscientist Seung-Schik Yoo at Brigham and Women's Hospital in Boston has shown that when a needle is placed in a point called pericardium 6 on the wrist, known in Chinese medicine as a sensitive point for nausea, the part of the brain that controls the vestibular system (which affects balance and nausea) lights up on scans.
While much about acupuncture remains mysterious, at least to Westerners, a great deal is becoming clearer, thanks to an explosion of studies using Western scientific techniques.
"The quality and amount of research being conducted now on acupuncture is improving greatly," said Peter Wayne, director of research at the New England School of Acupuncture, which has received $3.2 million in federal grants to study acupuncture on women undergoing chemotherapy for ovarian cancer, on teenagers with endometriosis, and on the accuracy of acupuncturists in diagnosing disease.
Acupuncture, an extraordinarily safe technique, has been used so far by 8.2 million Americans, according to the National Center for Complementary and Alternative Medicine, a division of the National Institutes of Health. Some insurers also now pay for acupuncture.
More than 40 clinical trials have shown that acupuncture reduces nausea after chemotherapy or surgery, said Ted Kaptchuk, an assistant professor of medicine at Harvard Medical School who is also a doctor of Chinese medicine.
In one of the best studies, Dr. Tong J. Gan, of Duke University Medical Center, showed last year that acupuncture on the wrist point was "as good as giving ondansetron," an anti-nausea drug, for post-operative nausea and vomiting.
The data on chronic pain and headache are somewhat mixed, but acupuncture clearly helps with dental pain, said Kaptchuk. But a recent, randomized, controlled study of 570 people with osteoarthritis of the knee showed that real acupuncture, as opposed to a fake form used as a control, reduced pain and increased function by about 30 percent.
"This is roughly the same effect size" as with ibuprofen-type drugs, said Dr. Brian Berman, the study leader and director of the Center for Integrative Medicine at the University of Maryland School of Medicine. At the moment, Berman recommends that patients use acupuncture with, not instead of, pain medications.
There is less data on acupuncture's ability to control pain in children, said Dr. Lonnie Zeltzer, director of the pediatric pain program at the Mattel Children's Hospital at UCLA. "But I believe it really does help. Most children accept acupuncture, and in fact, really feel good about it."
But perhaps the most intriguing scientific question is not whether acupuncture works, but how.
Since the 1970s, Western researchers have known that one of the ways acupuncture works is by releasing endorphins, the body's natural painkillers.
Acupuncture seems to calm precisely the part of the brain that controls the emotional response to pain, said Dr. Kathleen K. S. Hui, a neuroscientist at Massachusetts General Hospital, which has a $5 million federal grant to study acupuncture's effects on the brain. Her brain scan studies show decreased activation in deeper brain structures in the limbic system, which governs emotions and other physiological functions.
Researchers have also shown that acupuncture boosts levels of serotonin, which is often deficient in patients with depression. In addition, it lowers levels of norepinephrine and dopamine, which are often elevated during stress and pain.
Precisely how signals travel from acupuncture points to the brain is still a matter of some debate.
The bottom line? At long last, Western scientists are beginning to demonstrate, by their own standards, what Chinese acupuncturists have been saying for millenniums: that the effects of acupuncture are real. And that, at least for certain problems and to some degree, acupuncture can help relieve pain and suffering.
Judy Foreman's column appears every other week. Past columns are available on www.myhealthsense.com.