How Acupuncture May Work

How Acupuncture May Work

The compound adenosine is key to acupuncture's effectiveness, according to a study in Nature Neuroscience.  Despite acupuncture's 4,000-year history, little is known about the biological pathways that enable carefully placed needles to relieve pain in many patients.  Researchers mimicked acupuncture in mice by placing and gradually rotating a needle at a point just below the knee, for 30 minutes.  Levels of adenosine, a neurotransmitter, rose 24-fold in the tissue fluid surrounding the needle.  Mice injected with an inflammatory substance in their paws and given acupuncture displayed fewer pain symptoms than mice that didn't get acupuncture.  But mice genetically engineered to lack a certain adenosine receptor didn't benefit from the acupuncture session at all--further evidence of adenosine's role.  Blocking enzymes that break down adenosine made the acupuncture much more effective, tripling the level of adenosine near the needle and extending pain relief from about one hour to about three hours.

Pain Relief: Ginger appears to reduce exercise-induced muscle pain, according to a study in the Journal of Pain.  Researchers randomly assigned 74 adults to consume two grams of either ginger (raw in one experiment and heat-treated in another) or a placebo for 11 consecutive days.  On the eighth day, the participants performed series of bicep exercises tailored to mildly damage the muscle in their non-dominant arm.  One day later, participants who had been given ginger reported feeling about 25% less pain, on a scale from "no pain" to the "most intense pain imaginable," than subjects in the placebo group.  Though the precise pain-fighting mechanism is unknown, animal studies have shown that several chemicals in ginger reduce inflammation and the transmission of pain signals.  The results also jibe with previous trials of smaller doses of ginger extract over a longer treatment period, which reportedly reduced joint pain in arthritis patients.

Aging: One-fifth of the genes that help us recover from burns become less active with age, according to a study in the Proceedings of the National Academy of Sciences.  Previous studies have found that children recover more quickly from severe burns and are less likely to die from them than adults, but the precise reasons are poorly understood.  The authors of the PNAS study analyzed data from 57 patients--31 adults and 26 children--recovering from severe burns.  Each patient gave blood samples at two stages during his recovery: one within 10 days after the burn and the next between days 11 and 49.  By comparing these patients' genetic activity to a control group, the researchers identified several groups of genes most responsive to burn injury.  By comparing the burn victims' blood samples with one another, they found that 21% of these burn-response genes were less active in adults than in children.

Lung Function: Children whose mothers took vitamin A supplements during pregnancy had more powerful lungs than their peers, according to a study in the New England Journal of Medicine.  Animal studies have shown that vitamin A is crucial to lung development and elasticity, but the ultimate consequences of vitamin A deficiency on human lung function have been unclear.  More than 1,300 Nepali children, ages 9 to 13, participated in the study.  In the 1990s, researchers had randomized their mothers to receive either seven milligrams of vitamin A every week, the equivalent dose of beta-carotene (a less-efficient source of vitamin A) or placebo.  In the current study, researchers measured the volume of air each child could expel in one second.  By this indicator, children whose mothers received vitamin A supplements posessed lungs with about 3% greater power than average.  Children whose mothers received beta-carotene, however, performed no better than those in the placebo group.