Possible Appetite Suppressant Found in the Brain

All of us at sometime have gotten up from a table and either said or thought, “I can’t believe I ate the whole thing.” Generally before we overstuff our appetite is appeased and we quit eating. Looking at the statistics of obesity in this country makes it very clear that appetite control is not the same for everyone. People who are generally thin attribute obesity to lack of control among the overweight. This may be true for some but a study released in the November issue of the journal Cell suggests that the reasons for obesity may be more complex than just lack of control.

Researchers have looked for the mechanism that tells the body when it has had enough fatty food. The research has frustrated the searchers because levels of fatty acids—the building blocks of junk food—fall when people gorge on greasy foods. They increase as hunger increases. This prompted Gerald Shulman, a molecular biologist at Yale University and his team to scour blood for compounds that shot up after a fatty meal.

The scientists identified a chemical produced naturally in the digestive system that signals the brain when its time to stop eating. Researchers know that mice and rats, and presumably other species, produce the chemical after eating a fatty meal. The substance NAPE (N-acylphosphatidylethanolamine) is produced in the digestive system before heading to the blood stream. The chemical races to the brains appetite center and shuts down the hunger signals.

When the researchers gave the rodents an extra dose of NAPE over five days they ate less and shed weight without any apparent side affects. Mice and rats injected with normal levels of NAPE acted like they had gorged and showed little interest in eating. After five days on NAPE, rats ate 30 percent less food and lost a quarter of their weight. Rodents without NAPE gained a little weight.

The NAPE levels rose drastically after a fatty meal, but not when protein or carbohydrates were consumed. The effect may be the same in humans.

As people of the world eat diets higher in fat and get less exercise, scientists are searching for new ways to combat the increase in obesity. The findings of the recent study could give the direction for better drugs to suppress appetite and reduce obesity.
“We’re now doing the fat-feeding studies in humans to see if we get a similar increase in plasma (blood) NAPE concentrations following a fatty meal,” Shulman said. This could lead to a greater understanding of how the brain controls food intakes. Leptin, a hormone that helps to regulate this system, has had disappointing results as far as weight loss treatments for humans.

David Earnest, professor of neuroscience and experimental therapeutics at Texas A&M, Health Sciences Center College of Medicine said “The NAPEs work to suppress appetite or decrease food intake, but feeding is a complex behavior. A lot of factors figure into eating disorders. The findings are interesting and exciting basically because the NAPEs which are created in the gut and presumably can be used in supplementary fashion to treat obesity in humans. Unfortunately, things don’t always work out according to plan. Not to say that NAPEs don’t offer hope. These are some encouraging observations.”