Does weight loss really have to be the proverbial bitter pill? Researchers in Belgium who’ve studied how receptors in the gut respond to sweet, salty, bitter, sour, and umami taste sensations say the answer may be yes—literally.
In a review article published online today in Trends in Endocrinology and Metabolism, investigators at the Catholic University of Leuven suggest that the gut’s bitter taste receptors could be high-quality targets for potential drugs aimed at preventing or controlling obesity.
The gut’s ability to detect bitter tastes probably plays a role in limiting the absorption of toxins. It may seem counterintuitive, but the investigators said bitter tastes also boost secretion of the appetite-stimulating hormone ghrelin. Eating a meal then slows ghrelin production. Subsequently, the stomach muscle relaxes and the stomach empties more slowly, so a tempting dessert doesn’t seem quite so inviting.
Bitter tastes set in motion a cascade of events that “can result in early satiety and increase the interval between consecutive meals, with an overall reduction in food intake,” the authors wrote.
Additional studies have shown that isohumulones, the bitter compounds from hops used to make beer, improved insulin sensitivity in obese mice as well as in patients with type 2 diabetes, the researchers noted. Isohumulones also were effective in decreasing body fat in Japanese patients with prediabetes. In addition, a study of diabetes in Amish family members showed that malfunctioning bitter taste receptors in the gut impaired the balance of insulin and glucagon in the blood.
Despite the promising findings, researchers who pursue further studies have their work cut out for them, the investigators wrote. Some 25 receptors in the gut are involved in detecting bitter tastes, and each one may have very different effects on the release of hormones.
Nevertheless, they wrote that additional research is warranted “to investigate whether a bitter pill may be a promising tool in weight management.”