Friday, December 27, 2013

Weight Loss Acupuncture: Study Reports 5% Weight Loss in 8 Weeks. More Than the Exception That Proves the Rule?

It's the ear, not the belly that has to be (acu-)punctured to make the nasty pounds disappear.
I am pretty sure that at least some of you will have seen the headlines about one week ago: "Acupuncture Facilitates Effortless Weight Loss!" It sounds like a scam. If you actually read the corresponding press release, however, you'll have realized that the headlines were based on the results of a the results of a study that was conducted at the East-West Medical Research Institute of the Kyung Hee University in Korea, where the stimulation of the tested five ear acupuncture points (Shen-men, Spleen, Stomach, Hunger, Endocrine) has been used traditionally to curb the appetite of overweight patients for centuries.

6.1% and 5.7% reduction in BMI without diet or exercise

As it turned out, it was not even necessary to "nail" all 5 of the trigger points. As you will probably have learned from the press release, already, even the subjects in whom the researchers had "punctured" only the Hunger point lost 5% of their initial BMI within the 8-week study period.
Figure 1: Illustration of the trigger points and the results of the Yeo study (Yeo. 2013)
For the average slightly overweight Westerner with a weight of 100kg on a 180cm frame this 5%+ reduction in BMI would translate into a pretty significant decrease of ~5kg on the scale. An impressive figure, I know, but is this study actually more than a statistical outlier?
"How is this acupuncture thing supposed to work, anyway?" The absence of conclusive hypotheses that would explain the weight loss effects of acupuncture is actually one of the reason scientists doubt its efficacy. Theories that have been propose so far are generally based on the assumption that the trigger points are wired with the vagus nerve. Consequently, the stimulation of the auricular nerves could interfere with the transduction of appetite signals from the gastrointestinal tract (Dung. 1986).
If we take a look at the contemporarily available evidence, it is easier to find evidence to support the the results Yeo et al. present in their latest paper, than you may have thought:
  • Figure 2: Effects of 9 weeks of active or sham (inactive trigger points) acupuncture on % of subjects above ideal body weight; a good example of insignificant, but positive effects (Mok. 1976)
    Hsu et al. report a significantly greater weight loss and reduction in waist circumference with electroacupuncture treatment (vs. situp exercise or no intervention; Hsu. 2005).
  • Cabıoǧlu  et al. observed decreases in serum total cholesterol, triglyceride, and LDL cholesterol levels that were mediated by increases in serum beta endorphin in response to electroacupuncture of the ear points, Sanjiao (Hungry) and Shen Men (Stomach), and the body points, LI 4, LI 11, St 25, St 36, St 44 and Liv 3, once daily, for 30 minutes, for 20 days (Cabıoǧlu. 2005).
While these are not the only relevant studies, the fact that there are the general concerns with the quality of the corresponding paper, t  would be futile to attempt to cite all the contemporarily available evidence that would support the efficacy of acupuncture as a weight loss treatment. 

Scientists are still debating how acupuncture induced weight loss could work. The vagus nerve is yet part of almost every currently harbored hypothesis (Lacey. 2003).
In their 2001 review Linde, et al. use accupuncture as an example of the low rates of adequate allocation concealment and other shortcomings that may compromise their validity (Linde. 2011a). It is thus not really surprising, that you will also find conflicting evidence that would support our suspicion that Yeo's most recent study is nothing but a statistical outlier.
  • Despite using the exact same auricular acupuncture points, Hsu et al., whose previous study had yielded encouraging results (Hsu. 2005), did not observe significant differences in percent reduction in body weight, BMI, and waist circumference two groups of obese women, of which one received an active, one a sham treatment (Hsu. 2009)
This is a particular interesting result, because the most significant difference between the Hsu study from 2009 and the more recent study by Yeo et al. (2013) is actually the previously mentioned allocation concealment, or insufficient blinding, if you will. Contrary to the subjects in the Hsu (2009) study, Yeo et al. used no sham control, they simply "removed [the needles] immediately after insertion", again.

A similar argument is brought forward by Cho et al. who question the significance of their own generally positive assessment of the use of accupuncture as an obesity treatment (additonal weight loss of 0.50–2.93kg; Cho. 2008) due to the "poor methodological quality" of the 31 studies the Korean and Canadian researchers had reviewed.
Fat Loss Wraps: Green slime + cellophane, a similarly questionable weight loss alternative | learn more
Bottom line: In view of the insufficient blinding and contradictory results, it is not really suprising that reviews of the British Medical Association (2000), Ernst (1999) and Vickers et al. (2001) clearly state that the contemporarily available evidence would suggest that accupunkture does not promote weight loss. Linde et al. (2001b) and Tait et al. (2002) argue that the evidence was contradictory and a definitive answer to the question whether acupuncture can / will promote weight loss would require further, more rigorous and better controlled trials.

As of now, the Yao study is thus a methodologically somewhat questionable exception that proves the rule - the rule that says that diet and exercise are without any alternative.
References:
  • Cho, S. H., Lee, J. S., Thabane, L., & Lee, J. (2009). Acupuncture for obesity: a systematic review and meta-analysis. International Journal of Obesity, 33(2), 183-196.
  • Cabıoǧlu, T. M and Ergene, T. (2005) Electroacupuncture therapy for weight loss reduces serum total cholesterol, triglycerides, and LDL cholesterol levels in obese women. The American journal of Chinese medicine, 33.04, 525-533.
  • Dung, H. C. (1986). Role of the vagus nerve in weight reduction through auricular acupuncture. Am J Acup, 14(3), 249.
  • Ernst E. (1999) Clinical effectiveness of acupuncture: an overview of systematic reviews. In: Ernst E, White A, eds. Acupuncture: A Scientific Appraisal. Oxford, Butterworth-Heinemann.
  • Hsu, C. H., Hwang, K. C., Chao, C. L., Chang, H. H., & Chou, P. (2005). Electroacupuncture in obese women: a randomized, controlled pilot study. Journal of Women's Health, 14(5), 434-440.
  • Hsu, C. H., Wang, C. J., Hwang, K. C., Lee, T. Y., Chou, P., & Chang, H. H. (2009). The effect of auricular acupuncture in obese women: a randomized controlled trial. Journal of Women's Health, 18(6), 813-818. 
  • Lacey, J. M., Tershakovec, A. M., & Foster, G. D. (2003). Acupuncture for the treatment of obesity: a review of the evidence. International journal of obesity, 27(4), 419-427.
  • Linde, K., Jonas, W. B., Melchart, D., & Willich, S. (2001a). The methodological quality of randomized controlled trials of homeopathy, herbal medicines and acupuncture. International Journal of Epidemiology, 30(3), 526-531.
  • Linde, K., Vickers, A., Hondras, M., ter Riet, G., Thormählen, J., Berman, B., & Melchart, D. (2001b). Systematic reviews of complementary therapies-an annotated bibliography. Part 1: Acupuncture. BMC complementary and alternative medicine, 1(1), 3. 
  • Mok, M. S., Parker, L. N., Voina, S., & Bray, G. A. (1976). Treatment of obesity by acupuncture. The American journal of clinical nutrition, 29(8), 832-835.
  • Tait, P. L., Brooks, L., & Harstall, C. (2002). Acupuncture: evidence from systematic reviews and meta-analyses. Edmonton, Alberta, Canada: Alberta Heritage Foundation for Medical Research.
  • Vickers A. (2001). Acupuncture. Eff Health Care, 7:1–12.