Stimulation of auricular acupuncture points in weight loss

Dean Richards, MBBS, MDMA is in private medical acupuncture practice, South Australia.
John Marley MD, MBChB is Professor, Department of General Practice, The University of Adelaide, South Australia.

Objective - Many overweight people are aware that diets can help with weight loss but have difficulty in suppressing their appetite. Acupuncture stimulates the auricular branch of the vagal nerve and raises serotonin levels, both of which have been shown to increase tone in the smooth muscle of the stomach, thus suppressing appetite.

The aim of this study was to determine the effectiveness of transcutaneous electrical nerve stimulation of specific auricular acupuncture points on appetite suppression.

Methods - Sixty overweight subjects, randomly divided into an active and a control group, used the AcuSlim device twice daily for four weeks. The active group attached the AcuSlim to the acupuncture ear points shenmen and stomach, whereas the control group attached the device to their thumb where there are no acupuncture points. The goal of a 2 kg weight loss was set and changes in appetite and weight were reported after four weeks.

Results - Of those who responded, 95% of the active group noticed suppression of appetite, whereas none of the control group noticed such a change. None of the control group lost the required 2kg, with only 4 subjects losing any weight at all. Both the number of subjects who lost weight and the mean weight loss were significantly higher in the active group (p<0.05).

Conclusion - Frequent stimulation of specific auricular acupuncture points is an effective method of appetite suppression which leads to weight loss. 

Obesity is a common condition, associated with many health problems. Low joule diets may reduce weight but adherence to such diets requires the ability to sufficiently suppress the appetite.

Acupuncture may suppress appetite by controlling stress and depression via endorphin and dopamine production^1-3, by stimulation of the auricular branch of the vagal nerve and raising serotonin levels^2-4,11. Both vagal nerve stimulation and serotonin have been shown to increase tone in the smooth muscle of the gastric wall.⁸

The main auricular acupuncture points thought to raise serotonin levels, stimulate the vagus nerve and produce endorphins and dopamine are shenmen, stomach and lung (Figure 1).⁴

Acupuncture has been described as effective for weight loss^12-14 although constant stimulation of acupuncture points seems to lose effect, making frequent, intermittent stimulation preferable.⁴ Acupuncture and transcutaneous electrical nerve stimulation (TCNS) have been shown to be equally effective but to differ in their safety and complexity.^15,16

This double-blind randomised study utilised the AcuSlim, developed by SHP International Pty Ltd, which delivers non-invasive TCNS to auricular acupuncture points. The study aimed to investigate the effect of stimulating the auricular acupuncture points on appetite suppression and subsequent weight loss. 

Figure 1. The acupuncture points used by the treatment group are illustrated in the book Simple Health Maintenance. The points are no. 13 Shenmen and no. 20 Stomach.17
Teeth upper jaw Mouth Jaw and tonsil Teeth lower jaw Eye Inner ear Teeth lower jaw Tonsil Inner ear Foot Ankle Knee Shenmen - relax Wrist Hip Elbow Prostate all bladder Zero - relax Stomach	Liver Shoulder Lung and bronchi Heart Internal nose Toothache Neck Adrenal Pingchuan - asthma Endocrine Hunger Lumbar vertebrae Diaphragm Subcortex Triple warmer Large intestine Sympathetic External genitalia Uterus Kidney

Methods
Subjects
People having difficulty losing weight were recruited for the trial using talkback radio and press advertisements. Inclusion criteria were:

• being over the age of 18 years;
• having a reasonably stable body weight for at least 3 months.

Exclusion criteria were:

• patient already participating in any other weight loss regimen;
• pregnancy;
• patient taking hormone replacement therapy;
• patient taking anti-depressants;
• body weight exceeded 120kg;
• the presence of a serious concomitant disease or mental illness, such as depression;
• the presence of an eating disorder, for example, bulimia.

Sixty subjects matching the necessary criteria agreed to participate in the study.

Experimental protocol
The nature of the experiment was explained to subjects and they were informed they could withdraw from the trial at any time. Demographic information, medical history and history of previous attempts at weight loss were recorded. Subjects were randomly allocated to either an active or a control group. This was organised via a system of numbered envelopes and numbered cards.

Envelope numbers beginning from number one were given to each subject as they presented.

The cards in the envelopes contained the number of the device to be given to each subject.

The cards were in a randomised order.

The AcuSlim device, consisting of a small battery operated power pack with leads to two conductive electrodes, was used to non-invasively stimulate acupuncture points (Figure 2). All subjects used this acupuncture device for 15-20 minutes, twice daily. The control group attached electrodes at either end of the skin crease on the dorsal surface of the thumb where there are no acupuncture points (Figure 3). In the active group, one disposable electrode was attached to the auricular acupuncture point stomach and the other electrode, in the form of an ear clip, covered the ear point shenmen. Subjects in each group were given standard information about the AcuSlim including instructions on electrode adhesion and frequency and duration of stimulation. No specific diet was given to either group, however, all subjects received a copy of the 1,2,3,4,5 nutrition booklet, developed by the Anti Cancer Foundation, but were advised not to follow any specific weight reduction program, such as Weight Watchers during the program.

The initial weight of each individual was recorded before their allocation to a group and subjects were weighed again at 2 weeks and 4 weeks, with the final weighing done by a secretary who had no knowledge of the specific group involved. Patients were requested to wear the same clothing at each weighing session. Since the AcuSlim is designed for use at home, subjects were not required to report except to be weighed. At home, subjects were requested to record their fasting, bare body weight daily and to try weighing themselves at the same time under the same conditions each day. The subjects were blind to the group to which they belonged. They were asked to note any alteration in appetite during the trial.

Figure 2. The Acuslim device attached to the ear.	Figure 3. The control group attached the Acuslim to their thumb

Follow up
All subjects were given the opportunity to continue using the AcuSlim as described above and report again at the end of 12 weeks.

Statistical analysis
Measured variables were calculated as mean values ± standard deviation (SD). Initial data were analysed using the two sample t-test to ensure that no difference existed in subject characteristics between the active and control groups. The standard x² test for 2 x 2 table was conducted to ascertain that no gender bias existed between the two study groups. This test was also used to test for the presences of an association between the use of AcuSlim and appetite suppression and weight loss. The significance level was set at 0.05. 

Results
During the trial, five subjects from each group withdrew and were replaced when it was discovered that they did not fit the selection criteria for reasons such as pregnancy and busy lifestyle.

Subject characteristics
As determined by a x² test, no significant difference existed in gender balance between the active and control groups (p>0.05), although both groups contained more women than men. T-tests revealed that there was no difference between the active and control groups in the number of diets that had previously been attempted by subjects (p>0.05). No significant difference in subjects' age, height, initial weight or body mass index (BMI) existed between the two groups (p>0.05). These characteristics are displayed in Table 1.

Appetite change
Of the 32 subjects in the control group 28 subjects noted no change in appetite (Table 2). Twenty-one subjects (95%) in the active group commented on their appetite, with 20 reporting a decrease in appetite. So a significantly higher number of subjects in the active group reported a decrease in appetite (p<0.05). Four of the control group and seven of the active group failed to enter a comment as to alteration to appetite.

Weight loss
Average weight loss for all subjects, including increase for those in the control group who gained weight was:

• total weight lost 66 kg
• overall loss = average per subject 1.1kg (Figure 4).

Weight loss was significantly greater in the active group than the control group (p<0.05). In the active group, 93% of subjects lost weight during the four week period, with 78.5% losing at least the required 2kg (Table 3). Of subjects in the control group 12.5% lost weight, but no subjects in this group lost the required 2kg. For those subjects that did lose weight, the mean values were 0.63kg (SD 0.25kg) and 2.98kg (SD 1.35kg) in the control and active groups, respectively.

Figure 4. This scatterplot represents the weight change of control and active groups after one month, and for those who continued to report in the study at three months. None of the control group wished to continue past the one month.

Follow up
No subjects from the control group agreed to continue for longer than the four week trial. Ten subjects from the active group participated in the 12 week trial, but without a control group, statistical analysis was limited. One subject in the latter group developed an intercurrent illness and discontinued. Two other subjects did not lose or gain any more weight. The remaining seven subjects continued to lose weight and their weight loss at 12 weeks ranged from 6kg to 11kg. 

Discussion
Acupuncture has been used extensively in various dysfunctional states and for pain management. Problems include the aversion to needles, the fear of infection by needles and the occasional reported case of damage to vital organs by needle penetration. Needling of ear acupuncture points can become quite painful and may risk infection of the auricular cartilage. Attendance for conditions that require frequent treatment can become costly and inconvenient. However, in the case of weight control, or in the treatment of addictions such as nicotine, frequent acupuncture is essential for treatment to be effective. Embedded needles run similar risks and have been shown to lose effect over time.⁴

Therefore, a more satisfactory means of treating auricular acupuncture points with sufficient frequency to produce an effect in weight loss is by way of non-invasive treatment administered by the individual.

Research indicates that many obese people have low serotonin levels, and that serotonin stimulates the smooth muscle in the wall of the stomach.^6,7 Stomach wall tone is also controlled by the vagus nerve, the auricular branch of which is concentrated in the area of the acupuncture point, ear stomach. It has also been shown that acupuncture stimulation raises levels of both serotonin and relaxing neurotransmitter endorphins in the body.²

It has been demonstrated that acupuncture exerts its effect on pain by production of endorphins.

The fact that many pain sufferers receive long term relief from pain despite cessation of treatment, indicates that acupuncture may produce a long term rise in natural endorphin production by the body.

A similar parallel would assume that acupuncture may well produce a long term adjustment to normal production of serotonin by the body, in those with obesity associated with low serotonin levels. So it is feasible to expect that frequent stimulation of the auricular acupuncture points which bring about these changes in body chemistry, would assist in controlling excessive appetite in those with an obesity problem.

Weight and associated medical problems have occupied an increasingly prominent position in health costs. The financial cost of the various diets provided by the slimming industry is beyond many of those requiring long term weight loss support. Even if these diets prove to be successful, weight is often regained when the program ceases. Subjects in this trial who wished to lose weight commented that they were aware of the foods they should be eating but were unable to adhere to previous dietary restrictions. For many overweight people, the most difficult part of weight reduction is the establishment of a satisfactory eating pattern over the initial 4 week period. After this time they can often see evidence of weight reduction and this gives them confidence to continue. Subjects in the control group experienced significantly less appetite suppression and weight loss than the active group. This may help to explain why they did not continue with the AcuSlim for longer than the initial 4 week period.

Our findings indicate that regularly administered stimulation of the two auricular acupuncture points commonly used in weight control is effective in suppressing appetite such that an eating pattern is established in that initial 4 week period, which leads to weight loss.

In the trial many commented that once the AcuSlim induced a better eating pattern they could continue this without treatment.

Others stated that, if they showed signs of any increase in appetite or weight they simply resumed treatment to control this increase.

The follow up results imply that the AcuSlim may be successful in the maintenance of weight reduction. However, the long term potential of this device to result in permanent weight loss, remains to be evaluated. However this study offers hope for people who have been unsuccessful in other weight loss programs because they have not been able to control their appetite. Use of AcuSlim appears to be a simple, cost-effective method for losing weight and may be beneficial as an adjunct to any other form of weight loss program. 

Acknowledgments
The authors wish to thank Kristyn Willson for her statistical expertise, and Catherine Chittleborough for her contribution in preparing this manuscript for publication.

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