What studies imply about bulimia and thyroid cancer
In 1991, researchers at the National Institutes of Mental Health (NIMH) in Bethesda, Maryland published their study on what happened to thyroid hormone levels in those with bulimia nervosa. They had tested eight bulimic women during a cycle of one week of binge eating and vomiting and seven weeks of abstinence. (1)
The research team found that the T3, T4 levels fell significantly during the time when the women did not binge. The scientists concluded that binge eating and vomiting increases the activity in the thyroid gland.
Two years later, some of the same researchers on that Bethesda, Maryland team ran another study. This time they examined 18 people with bulimia during their binging cycle and after three weeks of abstinence. During admission, their thyroid hormone levels were in the normal range but their T3 levels were slightly lower than 28 control subjects. (2)
After three weeks of no binges, T3 and T4 had decreased significantly and thyrotropin were increased in the patients. The T3 levels correlated with intake of calories, protein, fat, and carbohydrates and were inversely correlated with weight. They hypothesized that binge-purge behavior may temporarily increase thyroid hormones and metabolic rate in those with bulimia nervosa. They also believe that when T3 decreases after abstinence, it may be because of the lower caloric consumption when not binging or it could reflect hypothalamic-pituitary dysregulation in individuals with BN.
In a 1996 study, 18 women with BN were followed during a period of active binging and vomiting and again after seven weeks of abstinence. The control group was 27 healthy women without BN.
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Again, during the binging phase, those with bulimia had lower T3 values than controls. During the no binging phase, they had lower levels of all thyroid hormones than controls. There were significant reductions in T3, T4, FT4 and TBG compared to the binging period. There was a positive correlation between calories consumed and TSH values, suggesting that binging may stimulate thyroid activity. (3)
None of these studies show any connection of bulimia and thyroid cancer. Polish researchers in 2017 commented in their medical journal that it’s possible for those patients with illness that doesn’t include the thyroid gland to have changes in serum thyroid hormone measurements that may indicate there is thyroid dysfunction occurring. The lab indices to be aware of are low T3, high RT4, and normal or inappropriately low T4 and TSH (thyrotropin) levels. How much thyroid function impairment there is correlates with the severity of the disease and low levels of thyroid hormones. Low levels of thyroxine predict a poor prognosis.
To date, there’s a lot of controversy about whether this fall in thyroid hormone levels is an adaptation to what’s happening and simply a way to conserve energy, or whether it is something that requires treatment.
Future studies may tell us more about whether there’s a connection between bulimia and thyroid cancer, but for the present, there is no knowledge of a connection.
If you need support in the treatment, and recovery from bulimia nervosa, please reach out to our team at Within today.