October 25, 2024, 8:49 am | Read time: 5 minutes

Bitter foods could possibly save your life! Researchers from Japan have provided evidence that bitter substances can apparently reduce the risk of type 2 diabetes and obesity. Polyphenols bind to receptors on the tongue and in the gastrointestinal system, where they release the hormone incretin, which is involved in suppressing appetite. Will bitter substances soon replace Ozempic and co.?

Japanese researchers wanted to better understand the connection between polyphenols, bitter taste receptors in the stomach and intestines, and the resulting health benefits. To do this, the researchers analyzed the existing studies on the possible effects of bitter substances. The results of their analysis could have far-reaching consequences for the prevention of the widespread disease diabetes mellitus, which affects 6.7 million people in Germany. An estimated two million are still unaware of their condition.¹

What are bitter substances (polyphenols), and in what are they abundant?

Polyphenols are a type of chemical substance that is found in natural foods but can also be produced artificially. In nature, they provide plants with natural protection against predators. We humans have sensitive taste sensors for bitter substances. This is how our ancestors were able to detect poisonous substances in plants. Bitter substances in pumpkins, zucchinis, or cucumbers, for example, can form bitter-tasting cucurbitacins, which can lead to nausea, vomiting, and diarrhea. However, the majority of the more than 8,000 polyphenols that give plants their bitter taste are extremely healthy.

Natural bitter substances are found in: Artichokes, broccoli, eggplant, Brussels sprouts, asparagus, fennel, celery, spinach, or radishes contain them. The lettuce varieties radicchio, rocket, endive, and chicory are also rich in bitter substances, just like grapefruits, pomelos, and lemons. Classic bitter herbs include mugwort, ginger, cardamom, lavender, dandelion, rosemary, sage, black cumin, cinnamon, and wormwood. Tip: The more naturally a plant has been allowed to grow, the more bitter substances it contains.

Receptors on the tongue, in the stomach, and intestines – how bitter substances work

Bitter substances stimulate the digestive juices in the body. First, they stimulate the bitter taste receptors (called TR2) on the tongue, which increases the flow of saliva and the enzymes it contains to start the pre-digestion process. The polyphenols also dock onto TR2 receptors in the stomach and later in the intestine. The stomach produces more hydrochloric acid, which improves blood flow to the gastric mucosa. The release of digestive juices and enzymes is also stimulated in the liver, gallbladder, pancreas, and intestine. For example, polyphenols can have a positive effect on the course of chronic inflammatory bowel disease in Crohn’s patients.²

Hope for obesity and diabetes – bitter substances can improve glucose tolerance

However, bitter substances have their greatest potential in the prevention of obesity and the associated diseases that affect so many people and lead to excessive mortality (see metabolic syndrome, which is usually based on insulin resistance). Polyphenols can improve glucose tolerance.

Type 2 diabetes develops in one in two men and one in three women over the age of 50 if they are obese.³ In these people, the body cannot use the hormone insulin sufficiently. As a result, the sugar remains in the blood, and the blood sugar level rises: Glucose tolerance is impaired.

Naomi Osakabe, Professor of the Department of Biosciences at the Shibaura Institute of Technology in Japan, launched a comprehensive review to understand the connection between polyphenols, bitter taste receptors in the gastrointestinal system, and glucose tolerance, which has now been presented. She and her team analyzed studies that had already dealt with this very topic and had come to exciting results. The Japanese researchers have now put these together to form a big picture.⁴

How does it work? Polyphenols promote the secretion of GLP-1

The scientists found that the key to the positive impact on glucose tolerance is the secretion of intestinal hormones involved in appetite suppression. They are secreted when the bitter taste receptors in the stomach and intestines are stimulated. More precisely, we are talking about incretins and cholecystokinin. Cholecystokinin is involved in triggering a feeling of satiety. Like the drug semaglutide, incretins inhibit the production of the insulin antagonist glucagon. To achieve this, semaglutide mimics the intestinal hormone glucagon-like peptide-1 (GLP-1 for short). Polyphenols promote the secretion of GLP-1 in a natural way.

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Fewer side effects – will bitter substances replace GLP-1 analogs such as Ozempic in the future?

Osakabe is not happy with the fact that type 2 diabetes and obesity can only be combated with so-called “weight loss injections” or diabetes medication – i.e., active ingredients such as semaglutide, like Ozempic. With her research, she is committed to developing new ways to regulate blood sugar levels and appetite. She points out that these drugs are also misused to prevent obesity by suppressing appetite. “These drugs always have side effects and are therefore a risky choice for use by the general population to prevent obesity and diabetes,” Medical News Today quotes the researcher as saying.

In contrast, polyphenols are “virtually absent” in the blood and “have been shown to cause few side effects,” Okasabe contends, “We believe that taking polyphenols is preferable because they are safer and demonstrate similar effects. Given the above, there is potential to replace current GLP-1-targeted drugs.”