The most common eating disorders are anorexia nervosa, where too little food is consumed, and bulimia, where there is self-induced vomiting after eating, typically after a binge. Bulimics may also abuse laxatives.
Worryingly, only around half of those with an eating disorder report ever being cured (Eukaryon, 2006; 2: 47-51).
Most treatments for anorexia and bulimia focus on the psychological aspects of the problem. However, increasing evidence points to a biochemical basis for these disorders. Indeed, many pioneers in the field of nutritional medicine are finding that much of so-called mental illness-the 'sick brain'-is, in fact, a biochemical imbalance that affects the mind as well as the body.
There are now a number of promising alternative treat-ments for sufferers of eating disorders.
Much research has looked at the role of zinc in eating disorders. Symptoms of zinc deficiency, such as weight loss, changed appetite and taste, depression and specific kinds of dermatitis, are also seen in anorexia (Med Hypotheses, 1979; 5: 731-6). Indeed, anorectics often have significantly lower levels of zinc than do healthy controls (J Am Coll Nutr, 1992; 11: 694-700; J Clin Psychiatry, 1989; 50: 456-9). Low zinc levels appear to have adverse effects on neuro-transmitters in the brain (Eat Weight Disord, 2006; 11: e109-11).
Zinc supplementation can improve appetite, taste sensation and mental state in anorectics (J Nutr Med, 1990; 1: 171-7; J Adolesc Health Care, 1987; 8: 400-6). Anorexia sufferers given zinc (14 mg/day for two months) are also reported to increase their BMI (body mass index) twice as fast as those given a placebo (Eat Weight Disord, 2006; 11: e109-11). As zinc supplementation works-and with no side-effects-one review has concluded that it should be routine treatment for anorexia (Eat Weight Disord, 2002; 7: 20-2).
Zinc is also promising in bulimia. In one study, 47 patients given 120 mL of liquid zinc sulphate for an average of 8.3 days showed significant improvement in reduction of "fat anxiety" and "body dissatisfaction" (Altern Med Rev, 2002; 7: 184-202).
Another nutrient that may be useful for eating disorders is niacin (vitamin B3). According to WDDTY panel member Dr Melvyn Werbach, a loss of appetite is one of the first symptoms of pellagra, a niacin deficiency. Indeed, several case reports describe pellagra in patients with anorexia (Altern Med Rev, 2003; 8: 180-5). Supplementing with niacin can improve appetite and mental state (Int Clin Nutr Rev, 1989; 9: 137-43).
Low levels of other B vitamins, including thiamine (B1), riboflavin (B2) folic acid (B9) and pyridoxine (B6), are also associated with anorexia and bulimia. Supplementing with these nutrients may therefore prove helpful (Rev Clin Esp, 1995; 195: 226-32; Postgrad Med J, 1986; 62: 853-4).
The neurotransmitter serotonin-necessary for mood regulation and appetite control-is another important factor in eating disorders. The amino-acid tryptophan is used by the body to make serotonin, and several studies have shown that, following a weight-reducing diet, levels of tryptophan in the body are also reduced (BMJ, 1990; 300: 1499-500).
When 11 young women with bulimia were given tryptophan (3 g/day) with 45 mg/day of vitamin B6, all experienced significantly improved mood, eating habits and views on food after just one month (Altern Med Rev, 2002; 7: 184-202).
Research shows that an upset in blood sugar-insulin levels may cause an eating disorder in the first place. Refined sugar given to animals can affect feeding behaviour and, in people, consuming high levels of carbohydrates, particularly sugar, can play a role in binge-eating (Brain Res Bull, 1985; 14: 673-80).
When 10 bulimic women went on a sugar-free, nutrient-dense diet for six weeks, they all stopped binging. When the
10 matched controls, who had been following a sham diet, switched to the experimental diet, they, too, became binge-free-and all participants remained so two-and-a-half years later (Physiol Behav, 1984; 33: 769-75).
Also, a high-protein diet significantly reduced binge-eating compared with a high-carbohydrate diet in patients with bulimia or binge-eating disorder (Int J Eat Disord, 2004; 36: 402-15).
Gentian root has had a long history of use in Germany and Switzerland for digestive disorders. It stimulates appetite and the flow of bile to help digestion, and can also be effective for even severe anorexia (Hippokrates, 1969; 40: 916-9; Krankenpflege [Frankf], 1975; 29: 99-100).
Other general appetite stimulants include alfalfa, catnip, cinchona and saw palmetto berry.