ADHD drug cuts adults' calorie, fat intake

NEW YORK (Reuters Health) - A single dose of Ritalin appears to dampen adults’ taste for calories and fat -- suggesting, researchers say, that the ADHD drug should be studied as a weight-loss medication.

Weight loss is known to be a potential side effect of methylphenidate, best known by the brand-name Ritalin. Whether the drug stands as a potential weapon in the battle of the bulge has been little studied, however.

Theoretically, Ritalin could help overweight people control their appetite because the drug increases brain levels of the chemical dopamine, which is involved in feelings of pleasure and “reward.”

Dopamine levels increase in response to food, and some research has suggested that people with normally low dopamine levels may be more vulnerable to becoming overweight because of the reward value they get from food.

“This is the theoretical basis for using Ritalin or other drugs that boost brain dopamine,” explained Dr. Gary S. Goldfield, the lead author of the new study. “We hope it will reduce appetite, possibly by reducing craving, wanting and/or the reinforcing value of food.”

To put that theory to the test, Goldfield and his colleagues at the University of Ottawa in Canada had 14 adults take either a dose of methylphenidate or a placebo shortly before offering the volunteers a buffet lunch.

They found that although the volunteers’ pre-lunch hunger ratings were no different whether they took methylphenidate or the placebo, the drug did cause them to eat less. On average, they downed 11 percent fewer calories, and 17 percent less fat, Goldfield and his colleagues report in the American Journal of Clinical Nutrition.

Since methylphendiate did not affect hunger, this suggests it might have dampened the rewarding effects of the food, according to the researchers.

“I would say that since methylphenidate ... reduced food intake and fat intake in only one administration, it should definitely be studied further as a potential weight-loss medication,” Goldfield told Reuters Health.

He cautioned, however, that it’s too soon for people to ask their doctors for a Ritalin prescription.

He said he and his colleagues are conducting a longer-term clinical trial to see whether the drug does in fact spur weight loss, and whether its effects on dopamine explain the benefit.

SOURCE: American Journal of Clinical Nutrition, August 2007.