I was a long-time skeptic of acupuncture. I didn’t have any training in the system during medical school, and it just didn’t make sense to me how needles inserted in seemingly random parts of the body could produce meaningful changes.

 

During my integrative medicine fellowship, my first rotation was with a practitioner trained in both conventional Western medicine and Classical Chinese medicine. Before spending time in his clinic, he suggested reading a book by Ted Kaptchuk, called The Web That Has No Weaver.1 This book helped me realize that acupuncture works from an entirely different framework than biomedicine, and helped me open to what I then saw in his clinic.

 

I was completely blown away. I saw patients with a huge array of conditions, many of which are difficult to treat from a Western perspective, who were clearly getting a huge benefit from the therapy. I immediately became a believer. And I’m not alone. In 2002, the World Health Organization (WHO) completed a review of clinical trials of acupuncture, noting its potential utility in treating dozens of conditions ranging from neurological and psychiatric disorders to gastrointestinal and dermatologic ailments.2 Acupuncture is used in 103 of the 129 countries that report data to the WHO, and the US National Health Interview Survey showed a 50 percent increase in the number of acupuncture users between 2002 and 2012.3

 

From an Eastern medicine standpoint, there isn’t a mystery as to why acupuncture works—one “believes” in acupuncture the same way one would “believe” in Western medicine—but the Eastern standpoint is a story for another post. What I found is that it can be difficult to articulate how and why it works in a Western context.

 

A number of theories have been proposed. Most of them I find to be unsatisfactory, though they have become increasingly sophisticated in recent years. Here are most of them:

 

Gate Control Theory – This theory suggests that acupuncture needles stimulate the release of endorphins and other neurotransmitters, which can block pain signals and influence how pain is perceived by the brain.

 

Neurotransmitter Theory – Acupuncture influences the release of various neurotransmitters (eg, serotonin and dopamine) that affect mood, pain perception, and other physiological processes.

 

Autonomic Nervous System Modulation (ANSM) Theory – Acupuncture influences the autonomic nervous system, helping to regulate various bodily functions (heart rate, digestion, immune response, etc).

 

Endorphin Hypothesis – This is similar to the gate control, ANSM, and neurotransmitter theories. Acupuncture works by stimulating nerves that release pain relieving hormones (eg, endorphins). These hormones can help suppress pain and increase mood, happiness, and pleasure. A broader version of this hypothesis is the neurophysiology model of acupuncture, in which acupuncture can have centrally acting effects that modulate brain function which then can cause trophic and anti-inflammatory effects peripherally.

 

Connective Tissue Theory – Acupuncture needles may stimulate connective tissue, which leads to a cascade of biochemical and mechanical processes that promote healing and relief.

 

Microcirculation Theory – Acupuncture increases blood flow and microcirculation in treated areas, which contributes to tissue repair and pain relief.

 

Placebo effect – The act of acupuncture itself produces a placebo response (through ritual and psychological influence), leading to a perception of benefits.

 

Each of these is interesting, but each also struck me as incomplete. When exploring the literature, I came across the work of Charles Shang, who argues that these models fail to answer four fundamental questions:4

 

1)    The distribution of acupuncture points. The distribution of acupuncture points is different from the distribution of nerves, blood vessels, lymphatics or connective tissue. The ear, for example, has no important nerves or blood vessels or lymphatics, but it has the highest density of acupuncture points. How?

2)    The non-specific activation of acupuncture points.  Acupuncture can create benefits by a variety of stimuli (including needling, injection of non-specific chemicals, electricity, temperature variation, laser and pressure). No conventional nerve stimulation technique has such diverse modalities of stimulation. Why?

3) Transient acupuncture stimulation often causes long lasting effect over weeks or months—thousands of times longer than the half-life of endorphins and other neurotransmitters. This benefit doesn’t happen in conventional treatments that use short term nerve stimulation. How?  

4)     The existence of acupuncture points. Why do stimuli at many acupuncture points cause diverse systemic effects without obvious benefit of survival for normal animals? What is the intrinsic function of acupuncture points, and how did they develop over the course of evolution? How did these acupuncture points come into existence over the course of evolution?

 

To address these questions, Dr. Shang proposed a new theory: the growth control theory. This is a model that is quite comprehensive – it can explain not only how acupuncture works, but also what the acupuncture points are. The theory is essentially a systems medicine understanding.

 

The growth control model encompasses many of the models above and suggests that a “growth control system” of the body originates from a network of organizers during the growth of an embryo. The activity of this growth control system is important in the formation, maintenance and regulation of all the physiological systems in the body. The growth control system develops over the course of the growth of the embryo, forming into organizing centers, or nodes—essentially, areas in the body where a lot of change is happening (kind of like major cities, or branch points in a tree or river). These nodes naturally occur at areas of greatest change and communicate with each other in the channels between cells, tissues, and organs. These organizing centers are the acupuncture points. The overall system is controlled by morphogens—growth factors—after development occurs.

 

Interestingly, organizing centers are a well-described concept in embryogenesis. Hans Spemman was awarded the Nobel Prize in Physiology or Medicine in 1935 when he discovered them, and the morphogens that drive embryologic growth.

 

It’s an elegant, sophisticated, and generally comprehensive theory. It explains why points exist, why the exist where they do, how they develop, and why stimulating the points works and can have lasting effect. It is consistent with a modern understanding of embryogenesis. In my mind, it is the most compelling explanation yet using biomedical principles.

 

The growth control theory can seem a bit complicated. As I was exploring this topic, I stumbled upon a book by Daniel Keown, The Spark in the Machine, that I found incredibly helpful in deepening my understanding.5 Keown is well equipped to describe it, since he is a trained acupuncturist (he trained in China for four years) and is a practicing emergency medicine physician in England. He subsequently wrote a text book, the Uncharted Body, that goes into much more detail.6

The take home point for me is that Western medicine is beginning to understand the complexity and sophistication of acupuncture, and that it has the capacity to transform how we think about healing.

 References

1. Kaptchuk TJ. The Web That Has No Weaver: Understanding Chinese Medicine. 2. ed., McGraw-Hill; 2000.

2. Acupuncture: Review and Analysis of Reports on Controlled Clinical Trial. World Health Organization; 2002.

3.         Acupuncture: What You Need To Know. NCCIH.

4.         Shang C. Prospective Tests on Biological Models of Acupuncture. Evid-Based Complement Altern Med ECAM. 2009;6(1):31-39. doi:10.1093/ecam/nem122

5.         Keown D. The Spark in the Machine: How the Science of Acupuncture Explains the Mysteries of Western Medicine. Singing Dragon; 2014.

6.         The Uncharted Body. Dr Dan Keown. https://drdankeown.com/store/the-uncharted-body-hardback