Recent data suggests that imbalances in serotonin the hormone involved in the regulation of feeding and mood remain altered in anorexia patients, even after weight restoration (Arch Gen Psychi, 1991; 48: 556-62).
Few studies have explored potential links between multiple chemical sensitivity and anorexia. Women use more highly perfumed products (toiletries and household cleaners) than men, and it is possible that an assault on the olfactory nerves from petrochemicals, which cross the blood brain barrier, can create chronic problems physical and psychological (Toxicol Ind Health 1992; 8: 181-202), in much the same way as glue sniffing. These things may be causes in their own right, or they may simply be the things which increase an individual's vulnerability.
Although many of the symptoms of anorexia mimic those of mercury poisoning, there is little information other than anecdotal on any possible links with sources of mercury toxicity, such as from dental amalgam and vulnerability to slimming disorders. WDDTY panellist Jack Levinson has commented that he has seen young girls diagnosed with eating disorders recover once their amalgam fillings were removed. Excess mercury, he says, blocks the body's absorption of zinc, and there are many studies which confirm that zinc deficiency could be a biological cause of anorexia.
Zinc deficiency and anorexia are similar conditions. Both tend to affect females between ages 12 and 25, and both are characterized by weight loss, changes in appetite and taste, yellowish skin pigmentation, depression and loss or irregularity of menstruation.
When Dr Rita Bakan and her colleagues at the British Columbia Institute of Technology conducted a clinical trial that used zinc supplementation to treat anorexia, they found that patients who received the supplement gained weight "significantly faster" than those who received a placebo (Townsend Letter for Docs, Nov 1993: 1154). In another study, those taking supplements also showed weight gain (Acta Psychi Scand, 1990; 361 (Suppl): 14-17).
Other practitioners have also assessed the zinc link (see Schauss, AG et al, Nutrients and Brain Function: 1987: 151-62; Ann Nutri Metab, 1992; 36: 197-202; J Clin Psychi, 1993; 54: 63-6) and found it a relevant factor in anorexia. One study concluded that anorexics have a lower intestinal uptake of zinc than normal subjects (Lancet, 1985; 1: 1041-42). Other studies have shown that anorexics and bulimics are deficient in zinc due to a variety of reasons lower dietary intake, impaired absorption, vomiting, diarrhea or binging on low zinc foods. Since zinc deficiency results in decreased food intake, it can be concluded that the acquired zinc deficiency of bulimics and anorexics could exacerbate their altered eating behaviour (J Clin Psychi, 1989;50: 456-9; see also J Am Coll Nutri, 1992; 11: 694-700).
Many bulimics perceive themselves as being uncomfortably full thus the rationale behind induced vomiting or abusing laxatives. In one study, normal weight female bulimics who had abstained from binge eating and purging for at least a month were studied. What the researchers found was that they had irregularities in the hormonal process that regulates fluid volume in the body a fact which may be relevant to their behaviour (J Clin Endocrinol and Metab, 1992; 74: 1277-83).
Pre existing hormonal imbalances are also common in anorexics. Indeed, amenorrhea develops in many patients before the onset of substantial weight loss has occurred, and age inappropriate gonadotrophin secretion patterns are present in some patients who are weight recovered (see Pirke, KM et al, The Psychobiology of Anorexia Nervosa, New York: Springer-Verlag, 1984; 46-57).