Background: Several studies report reduced serotonin (5HT) in alcohol-dependent subjects. Furthermore, alcohol increases 5HT in animals. Thus, alcohol dependence may be an attempt to self-medicate reduced 5HT. Relevant to this, reducing 5HT increases carbohydrate intake, and several studies report increased carbohydrate intake in alcohol-dependent subjects. Like alcohol, carbohydrate increases 5HT. We hypothesized that a subgroup of the alcohol-dependent population self-medicates reduced 5HT with alcohol and alternatively with carbohydrate when not drinking.
Methods: Three groups were recruited: a high carbohydrate craving alcohol-dependent group (n = 10), a low carbohydrate craving alcohol-dependent group (n = 11), and a nonaddicted control group (n = 12). All groups were placed on a high-carbohydrate, low-protein diet for 2 days and then a high-protein, low-carbohydrate diet for 2 days. The effects of diet on mood, alcohol craving, stress, and 5HT were measured.
Results: Although both alcohol-dependent groups had similar alcohol cravings at baseline, only the carbohydrate-craving alcohol-dependent group craved alcohol significantly more when under the stress of the research protocol. The carbohydrate-craving alcohol-dependent subjects presented with distinct personality disorders and were uniquely sensitive to the adverse effects of carbohydrate on mood. Diet had a unique effect on 5HT in the high carbohydrate craving alcohol-dependent group. The results of platelet 5HT uptake demonstrated that the high-protein, low-carbohydrate diet significantly increased Km values of high carbohydrate craving alcohol-dependent subjects, whereas it reduced the Km values of both non-carbohydrate-craving alcohol-dependent subjects and nonaddicted controls.
Conclusion: Carbohydrate-craving alcohol-dependent subjects are a distinct subgroup of the alcohol-dependent population.