Eating disorders are complex conditions involving psychological factors and nutritional deficiencies. The term eating disorders includes anorexia nervosa, bulimia, and binge-eating.
The psychological factors may include an inability to cope with stress, problems with family and other relationships, feelings of deprivation, and experiences of physical, sexual, or emotional abuse. Psychotherapy is an essential part of the treatment for eating disorders, along with nutrition counseling and medical care as needed.1
A person with anorexia does not eat enough to maintain a healthy weight; she views herself as overweight and is anxious about gaining weight. Anorexia typically begins in early adolescence, mainly among girls, though the numbers of boys developing this condition is increasing. People with anorexia weigh less than 85% of the normal weight for their age and height. Excessive exercise, vomiting, and abuse of laxatives and/or diuretics may also occur. Severe anorexia can be life threatening.
Bulimia, also known as bingeing and purging, is more common than anorexia, and usually affects teenage girls and women in their twenties. It involves a recurring, emotionally driven cycle of compulsive consumption of large quantities of high-calorie food in a short period of time, followed by induced vomiting. Some individuals also use laxatives, drugs that induce vomiting, diuretics, or excessive exercise in an attempt to purge. About 50% of anorexics also purge, and both bulimia and anorexia can coexist in the same person.2 Unlike those with anorexia, some people affected by bulimia maintain normal or even excessive body weight.
Binge-eating disorder is similar to bulimia but no purging is done. It is more common than either bulimia or anorexia nervosa, and people with binge-eating disorder are usually overweight.3
What are the symptoms of eating disorders?
People with eating disorders may have a preoccupation with weight and food, anxiety about their body image, and/or a feeling that they lose control over how much they eat. They may also exercise compulsively and, in women, experience missed menstrual periods. They may also frequently use laxatives, diet pills, and medicines designed to induce vomiting or reduce fluid retention.
Dietary changes that may be helpful for eating disorders
The most important dietary change for people with eating disorders is to eat a sufficient amount of calories without purging. To accomplish this, most will need psychological as well as nutrition counseling.
Individuals with both bulimia and anorexia are likely to report a craving for sugar; people with bulimia eat more sweets and carbohydrates, particularly during binges, than do healthy individuals.4 5 6 7 In a double-blind study, bulimic subjects were reported to have significantly more mood changes after receiving glucose (corn sugar) injections compared to placebo injections.8 Preliminary evidence suggests that purging results in low blood sugar, which might increase the incidence of repeated bingeing and purging by stimulating appetite or altering mood.9
In a preliminary trial, researchers fed ten bulimic women a diet free of all alcohol, caffeine, refined sugar, and foods containing white flour, added salt, monosodium glutamate, and flavor enhancers. They were also given 1 gram of vitamin C, 50 mg of a vitamin B-complex, and a multiple vitamin and mineral supplement.10 Cigarette smoking was not allowed during the trial. After three weeks, all women on this diet plan stopped bingeing whereas another ten bulimic women consuming a normal diet continued to binge. When the women who had been eating a normal diet were also placed on the more healthful diet plan, they too stopped bingeing. All 20 women remained binge-free for more than two and a half years.
Lifestyle changes that may be helpful for eating disorders
Although regular, moderate exercise offers important health benefits, for many people excessive exercise is a common component of eating disorders, especially anorexia nervosa.11 In one controlled trial, a majority of the people with eating disorders reported that participation in competitive sports and exercise performed as part of a weight loss plan contributed to their condition.12 For people with eating disorders, it is important to establish and maintain healthy exercise habits; these individuals should consult with a healthcare professional skilled in eating disorders.
Nutritional supplements that may be helpful for eating disorders
People with eating disorders who restrict their food intake are at risk for multiple nutrient deficiencies, including protein, calcium, iron, riboflavin, niacin,13 folic acid,14 vitamin A, vitamin C,15 and vitamin B6,16 and essential fatty acids.17 A general multivitamin-mineral formula can reduce the detrimental health effects of these deficiencies.
In a preliminary study of women with anorexia nervosa, those who supplemented with 45 mg of vitamin K2 per day for approximately one year experienced significantly less bone loss, compared with women who did not take the supplement.18 This study suggests that supplementing with vitamin K2 may help prevent osteoporosis, which is a common complication of anorexia nervosa. The amount of vitamin K2 used in this study was much larger than the amount of vitamin K found in food and most supplements. Moreover, vitamin K2 is not yet generally available as a supplement, although it can be obtained through some nutritionally oriented doctors. Individuals interested in using this treatment should be monitored by a doctor.
Zinc deficiency has also been detected in people with anorexia or bulimia in most,19 20 though not all,21 studies. In addition, some of the manifestations of zinc deficiency, such as reduced appetite, taste, and smell, are similar to symptoms observed in some cases of anorexia or bulimia.22
In an uncontrolled trial, supplementation with 45–90 mg per day of zinc resulted in weight gain in 17 out of 20 anorexics after 8–56 months.23 In a double-blind study, 35 women hospitalized with anorexia, given 14 mg of zinc per day, achieved a 10% increase in weight twice as fast as the group that received a placebo.24 In another report, a group of adolescent girls with anorexia, some of whom were hospitalized, was found to be consuming 7.7 mg of zinc per day in their diet—only half the recommended amount.25 Providing these girls with 50 mg of zinc per day in a double-blind trial helped diminish their depression and anxiety levels, but had no significant effect on weight gain. Anyone taking zinc supplements for more than a few weeks should also supplement with 1 to 3 mg per day of copper to prevent a zinc-induced copper deficiency.
Serotonin, a hormone that helps regulate food intake and appetite, is synthesized in the brain from the amino acid L-tryptophan. Preliminary data suggest that some people with bulimia have low serotonin levels.26 Researchers have reported that bulimic women with experimentally induced tryptophan deficiency tend to eat more and become more irritable compared to healthy women fed the same diet,27 28 though not all studies have demonstrated these effects.29
Weight-loss diets result in lower L-tryptophan and serotonin levels in women,30 which could theoretically trigger bingeing and purging in susceptible people. However, the benefits of L-tryptophan supplementation are unclear. One small, double-blind trial reported significant improvement in eating behavior, feelings about eating, and mood among women with bulimia who were given 1 gram of L-tryptophan and 45 mg of vitamin B6 three times per day.31 Other double-blind studies using only L-tryptophan have failed to confirm these findings.32 33 L-tryptophan is available by prescription only; most drug stores do not carry it, but “compounding” pharmacies do. Most cities have at least one compounding pharmacy, which prepares customized prescription medications to meet individual patient’s needs.
Another serotonin precursor, 5-hydroxytryptophan (5-HTP), has been shown to reduce appetite in weight-control and diabetes trials.34 35 36 However, what effect 5-HTP has, if any, on people with binge eating disorder, bulimia, or anorexia is unknown. Unlike L-tryptophan, 5-HTP is available from health food stores and some pharmacies without prescription.
Are there any side effects or interactions with eating disorders?
Refer to the individual supplement for information about any side effects or interactions.
Holistic approaches that may be helpful for eating disorders
Psychological counseling, for both the individual and her family, and behavior modification training are also commonly used for people with eating disorders, often as part of a team approach that also includes nutrition counseling and medical care. Numerous preliminary and controlled studies have shown that the psychotherapy technique known as cognitive-behavioral therapy is effective in reducing the symptoms of bulimia.37 38 For example, one study found 69% of a group receiving cognitive-behavioral therapy were abstaining from binge-eating and purging six months later compared to only 15% of a group keeping a diary of their behavior.39 Preliminary studies40 and one controlled trial41 suggest another technique, interpersonal psychotherapy, is equally effective for people with bulimia. Cognitive behavioral therapy and interpersonal psychotherapy have also been effective for people with binge-eating disorder in controlled trials,42 43 resulting in cessation of binge-eating in almost half of the subjects in one report.44
The effectiveness of psychotherapy for anorexia nervosa is less clear.45 46 One controlled trial found that psychotherapy (type unspecified) significantly improved weight gain compared to no treatment, and complete or nearly complete recovery occurred in 60% of the patients.47 Two other studies comparing different types of psychotherapy for anorexia nervosa found comparable improvement from all types;48 49 one of these studies reported moderate improvement in 63% of cases.50 Long-term effectiveness of psychotherapy for eating disorders has not been studied.