Coming: drug therapy for chocoholics?

Few foods top chocolate's popularity. The 2.86 billion pounds of this candy shipped annually in the United States contribute to an average per capita consumption of more than 11 pounds.

New data now suggest that in especially vulnerable people, the ready availability of this and other sweet, fatty foods can fuel a binge-eating addiction. But drugs that block naturally produced opiates--heroinlike chemicals in the brain--can help binge eaters break their periodic compulsion

to overeat, a pair of new studies indicates.

Nutritionist Adam Drewnowski of the University of Michigan School of Public Health in Ann Arbor and his coworkers studied 16 obese women and 25 women of normal weight. Ten women in each group met the criteria for either bulimia or a "binge-eating disorder" listed in the latest Diagnostic and Statistical Manual of Mental Disorders.

On three occasions, the women rated their preference for foods in four categories: those low in fat and sugar (including popcorn and pretzels), low in fat but high in sugar (including jelly beans), high in fat but low in sugar (such as potato chips and cream cheese), and high in both fat and sugar (chocolate in candy and cookie form).

Each woman then received at random a 2.5-hour-long infusion of naloxone (which blocks the action of the brain's natural opiates), salt water, or butorphanol (a drug that can both potentiate and block opiates). An hour into

the treatment, researchers again assessed food preferences, then gave each woman a tray containing personally identified favorites from each category, with instructions to eat all they wanted.

Though naloxone diminished each woman's preference for sweet and, especially, fatty foods, it did not affect perceptions of sweetness or fattiness. However, in women diagnosed as binge eaters--whether obese or lean--that change in preference also translated into a change in eating choices, the Michigan researchers report in the June American Journal of Clinical Nutrition.

Obese binge eaters ate fewer calories during the naloxone treatment, and all binge eaters reduced their consumption of sweet, fatty fare, compared to the two other treatments. Lean and obese nonbinge eaters, by contrast, ate the same type and amount of food in all three sittings.

"Our study is the first psychobiological validation that there is something special about binge eaters, whether lean or obese," Drewnowski told Science News. Only the binge eaters changed eating patterns in response to opiate blocking. Because all of the study's sweet, fatty foods contained chocolate, he notes, one can't tell whether chocolate is unusually addictive. But, he adds, it is the food most craved by women.

Pharmacologist Mary Ann Marrazzi says this study confirms what her team at Wayne State University in Detroit saw in a 6-week trial with 19 bulimic and anorexic binge eaters. In the next International Clinical Psychopharmacology,

her team will report that daily treatment with another brain-opiate blocker reduced the number and intensity of binges in all but one person.

"It interrupts their addictive cycle," Marrazzi says, "so that psychotherapy can be more effective."