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October 2001; Volume 4; 114-117
By Judith Balk, MD, FACOG
Obesity is a maladaptive increase in the amount of energy stored as fat. The prevalence of obesity in the United States is high. Complications from obesity include insulin resistance, noninsulin-dependent diabetes mellitus, hypertension, atherogenic lipid profile, coronary vascular disease, stroke, gout, exacerbation of arthritis, and many other diseases. The etiology of obesity is multifactorial, and as such, the treatment is often multifaceted.
The main goal of obesity treatment is to lower energy intake below that of energy expenditure. Conservative approaches, such as diet, nutrition education, behavior modification, and exercise, may be used. Self-help groups include Overeaters Anonymous, and commercial programs include Weight Watchers. The attrition rate of commercial programs is very high: 50% at six weeks and 70% at 12 weeks.1
Commercial programs do not have high success rates for most participants. Other treatment approaches include pharmacotherapy, surgery, lifestyle modification, and acupuncture. Acupuncture has been used rarely to treat obesity; roughly 1% of acupuncture consultations to British traditional acupuncturists are for the treatment of obesity.2
Traditional Chinese Medicine and Obesity
Traditional Chinese medicine (TCM) differs from Western medicine in its perspective of disease. In TCM, the main causes are due to imbalances of chi, and treatment is based on the particular imbalance.3 For instance, obesity with shortness of breath, general lassitude, and puffiness of the lower limbs belongs to the category of dampness in the spleen and stagnation of phlegm. Obesity with overeating, strong body composition, and dry stools belongs to excessive heat in the spleen and stomach. Obesity with bulimia, irregular menstruation, and a dark purplish tongue belongs to the qi stagnation and stasis of blood category.
Herbal concoctions are prescribed to treat the appropriate syndrome. Acupuncture also may be used, and points on the body and on the ear are common. Ear acupuncture also is called auricular acupuncture, and may include the use of acupuncture needles, tacks held in place by tape, staples, transcutaneous electrical nerve stimulation units, or acupressure. (See Table.)
|Table: Commonly used auricular acupuncture points16|
|Lung||Inferior concha||Relieves respiratory eating disorders and drug addiction problems such as smoking withdrawal, cocaine addiction, and alcoholism.|
|Stomach||Conchal ridge||Relieves eating disorders, diarrhea, gastritis, and indigestion.|
|Hunger (also called
|Tragus||Diminishes appetite and facilitates weight reduction.|
|Mouth||Inferior concha||Relieves eating disorders, mouth ulcers, cold sores, and glossitis.|
|Shen Men||Triangular fossa||Alleviates stress, pain, anxiety, depression, insomnia, and restlessness. Supports all other auricular points.|
Mechanism of Action
Several mechanisms have been proposed to explain acupuncture’s anecdotal success in treating weight loss. Acupuncture appears to normalize the sympathetic-adrenal and hypothalamus-pituitary-adrenal systems in overweight adults.4 The authors suggest that this may regulate the metabolism of carbohydrate, lipid, and protein, and enhance central nervous system excitation.
Appetite and feeding are controlled in a very complex manner by the brain. Two areas in particular are involved: the ventromedial nucleus of the hypothalamus (VMH) and the lateral hypothalamus (LHA). The VMH is thought to be the satiety center, whereas the LHA is thought to be the feeding center. Acupuncture may activate the satiety center in the brain.5
A different mechanism may be mediated through the vagus nerve. One author suggests that innervation of the concha by the auricular branch of the vagus nerve may explain the beneficial effects of acupuncture.6 Dung hypothesizes that mechanical stimulation of the auricular nerve causes a dispatch of neuronal impulses to the central nervous system via the vagus nerve.6 These impulses can interfere with an appetite signal coming from the gastrointestinal tract. Thus, the appetite signal may be partially blocked, resulting in less hunger.
Less hunger also could arise if gastric emptying is slowed. A clip that attaches to the tragus prolongs gastric peristalsis time.7 Gastric peristalsis returned to baseline when the clips were removed.
Another mechanism proposed is via serotonin. Serotonin has been shown to increase tone in the smooth muscle of the gastric wall. Auricular acupuncture points are thought to raise serotonin concentrations and produce endorphins and dopamine.8
In a controlled study, obese rats were randomized to receive acupuncture or not, and were compared to a non-obese control group.9 Rats were treated once daily with body acupuncture for 12 days. The animals in the acupuncture group lost weight; the other two groups gained weight. Because the obese control group did not receive body acupuncture, it is possible that the needles caused the weight loss. The second part of the study entailed brain monitoring: Electric activity of the brain satiety center increased with acupuncture. This could translate into greater satiety and lower caloric intake.
Auricular stimulation caused changes in LHA and VMH in obese and normal rats.10 LHA neuronal activity was depressed and VMH activity was excited with auricular acupuncture. Satiety was more affected than appetite. Changes in brain activity correlated with the degree of obesity, suggesting that acupuncture would not have much effect in a non-obese population. Another study found that the VMH was stimulated with auricular acupuncture of therapeutic points (e.g., stomach and lung) and the rats lost weight.5 When non-therapeutic acupuncture points were needled, the VMH was not affected nor did the rats lose weight. Also, after the VMH was lesioned, acupuncture had no effect on body weight. Thus, it appears that the satiety center may be involved in decreasing weight.
Five clinical trials that utilized a placebo control group were identified. Marked heterogeneity in treatment protocols exists. Also, the outcome variables differ between studies. Ideally, an objective outcome, such as correctly measured weight, is used; using a subjective outcome variable such as hunger or appetite is less ideal. For research purposes, an objective outcome is necessary to make firm conclusions.
One clinical trial included 24 subjects ranging from 5-33% above ideal body weight.11 Subjects were treated with three different protocols in a random order over a nine-week period. The three groups were treated in the following manners: mouth and stomach points unilaterally; mouth and stomach points bilaterally; or ankle and shoulder points, which were the placebo control points. Both active point groups lowered their percentage above ideal body weight by 0.9; the placebo group had no change. This difference was not statistically significant. Analysis of questionnaires showed variable responses of acupuncture on appetite, ranging from no effect to a sensation of early satiety, with generally decreased hunger. An animal study that ran in conjunction with this clinical trial demonstrated no weight loss with acupuncture.
Allison et al also used weight change as the primary outcome variable.12 An auricular acupressure device was studied in a placebo-controlled trial of 96 subjects for 12 weeks. The device was a molded ear piece with six strategically placed bumps. The placebo group wore a wrist acupressure device. It is not stated which acupressure points were stimulated with the device. Subjects in the treatment group lost 1.28 kg, and those in the control group lost 0.63 kg. This difference was not statistically significant. Ear problems, such as pain and redness were higher in the treatment group. Self-reported weight loss was higher in the treatment group than in the placebo group (P = 0.048).
A different clinical trial enrolled 30 subjects.13 All subjects were given a 1000 Kcal/d diet. Three groups were formed: bilateral stimulation of the stomach point; bilateral stimulation of the hunger point; and bilateral stimulation of a placebo point. Subjects were treated for 25 min/d, five days per week, for three successive weeks, and assessed for ability to follow the prescribed diet regimen. The majority of subjects in the active groups (80% and 70% for the stomach and hunger points, respectively) were able to follow the diet regimen; only 20% in the placebo group were able to follow the diet. Among subjects unable to follow the diet, weight did not change. Those that followed the diet lost weight (range: 1-4 kg). The amount of weight loss did not differ for those who were able to follow the diet. The authors concluded that the effect of acupuncture on body weight reduction was secondary to motivating the subject to stay on a diet.
Another randomized, placebo-controlled trial included 120 subjects for six weeks.14 Subjects were asked not to diet, and if the auricular acupuncture point was not effective after two weeks, it was changed. Of those who failed treatment with the stomach, lung, or placebo points, 70% had abatement of hunger and weight loss when treated with the hunger point. The lack of a true control group, as the control group was changed prior to the end of the study, and the use of a subjective main outcome variable limit the usefulness of this study.
Recently, a pilot study evaluating the effects of minimal acupuncture versus moxibustion and acupuncture was conducted.15 Forty obese subjects were randomized to one of two weekly acupuncture sessions. A very high dropout rate existed; 30% of patients in the treatment group and 60% of those in the placebo group dropped out. No differences existed between groups for weight loss, but anxiety and depression improved in the treatment group compared to the placebo group. The high dropout rates limit the usefulness of this study.
The main risks of auricular acupuncture include tenderness, infection, and chondritis. Long-term application of needles can result in a "cauliflower ear." As with acupuncture elsewhere on the body, some patients become drowsy after auricular acupuncture.
No firm evidence exists to suggest that acupuncture improves weight-loss efforts; the clinical trials that do exist have methodological issues. If weight loss were as simple as not eating when one was not hungry, then obesity would not be the problem it is today. Thus, even if it is possible to affect the satiety center via acupuncture, weight management must address much more than just the sensation of satiety.
The current state of knowledge neither supports nor refutes the possibility that acupuncture is beneficial for weight loss. The goal of weight loss efforts should be to lower energy intake below that of energy expenditure. Means of achieving this should be long-lasting and multifaceted. Acupuncture cannot reliably be continued daily or weekly for long periods of time and hence it is not likely to be of long-term benefit.
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