Bitter polyphenols in plant-based foods may help lower obesity and diabetes risk

ISLAMABAD, August 31 (Online): Polyphenols are a type of chemical naturally occurring in plant-based foods that are antioxidants.
Because polyphenols taste bitter, they interact with the bitter taste receptors on the tongue, known as the Type 2 taste receptors (TR2).
Past studies show that TR2 taste receptors are not only on the tongue, but can also be found in other body organs, including those that make up the gastrointestinal system.
Researchers from Shibaura Institute of Technology in Japan have found that polyphenol-caused activation of T2R in the GI tract causes the secretion of hormones that may help lower a person’s risk of developing type 2 diabetes and obesity.
Polyphenols are a type of chemical naturally occurring in plant-based foods like fruits, vegetables, whole grains, and nuts and seeds.

There are more than 8,000 types of polyphenols, all of which are antioxidants that have the potential to protect the body’s cells from aging and damage from outside factors like injuries, environmental pollution, smoking, and eating processed foods.

Because polyphenols are generally considered to taste bitterTrusted Source, they interact with the bitter taste receptors on the tongue, known as the Type 2 taste receptors (TR2)Trusted Source.

Past studies show that TR2 taste receptors are not only on the tongue, but can also be found in other organs and tissues of the body, including those that make up the gastrointestinal system.Trusted Source

“Recently, it has been reported that bitter taste receptors are widely expressed in the digestive tract and are involved in the secretion of incretinTrusted Source, a digestive hormone, and appetite suppression,” Naomi Osakabe, Ph.D., professor in the Department of Bioscience and Engineering at the Shibaura Institute of Technology in Japan told Medical News Today.

To help clarify how this works, Osakabe took the lead on a new study focused on the relationship between the bitterness of polyphenols and glucose tolerance.

Researchers found that polyphenol-caused activation of T2R in the gastrointestinal tract causes the secretion of hormones that help regulate appetite and blood sugar, including glucagon-like peptide-1 (GLP-1)Trusted Source.

Together, scientists believe the gastrointestinal hormones triggered by polyphenols could help reduce a person’s risk for both obesity and type 2 diabetes.

Polyphenols and diabetes risk
Through their study, Osakabe and her team wished to better understand the connection between polyphenols, T2R in the gastrointestinal tract, and potential health benefits.

Previous studies show that polyphenols may help lower a person’s risk for type 2 diabetesTrusted Source and obesity,Trusted Source as well as other health conditions including high cholesterolTrusted Source, high blood pressureTrusted Source, osteoporosisTrusted Source, Alzheimer’s diseaseTrusted Source, and certain cancersTrusted Source such as colorectal cancerTrusted Source.

“Despite their poor absorption, there are reports that polyphenols improve glucose tolerance,” Osakabe said in a press release. “We are investigating the relationship between polyphenol intake and the risk of type 2 diabetes, as the mechanism of this beneficial effect is still unknown.”

Through their research, the scientists discovered that polyphenol-caused activation of T2R in the gastrointestinal tract causes the secretion of gastrointestinal hormones including cholecystokinin (CCK)Trusted Source and incretins like GLP-1.

Both CCK and GLP-1 are known to help decrease appetite and regulate blood sugar levels.

Potential to replace current GLP-1 drugs
Osakabe said that it is important for researchers to continue to find new ways to regulate blood sugar levels and appetite to help combat conditions like type 2 diabetes and obesity because medications currently used to treat diabetes many times have side effects, and there are no drugs that can be used preventively by the general population.

“Type 2 diabetes results in impaired glucose tolerance, but the receptor agonists for the gastrointestinal hormone GLP-1, currently used in clinical practice, markedly improve this,” she explained.

“They are also abused because of their effect in preventing obesity by suppressing appetite. These drugs always have side effectsTrusted Source and are, therefore, a risky choice for use by the general population for the prevention of obesity and diabetes,” she continued.

“GLP-1 receptor agonists are absorbed and act on GLP-1 receptors in target organs and cause unintended gastrointestinal disturbances and adverse effects on blood glucose. Similarly, an essential characteristic of polyphenols that stimulate GLP-1 secretion is that they are virtually absent in the blood and have been shown to cause few side effects. We believe that the intake of polyphenols, which are safer and show similar effects, is preferable. Given the above, there is potential to replace current GLP-1-targeted drugs.”
— Naomi Osakabe, Ph.D.

More potential for body regulation through food than we realize
After reviewing this study, Mir Ali, MD, a board certified bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, told MNT he found the research to be very interesting.

“There’s a lot more potential to help regulate our bodies from food than we realize, so this study is demonstrating that if we perhaps add certain foods and things to our diet, we can improve our health,” Ali explained.

“Both diabetes and obesity are on the rise, so anything we can do to find ways to combat this is going to be helpful. There [are] medications and surgeries and things out now, but anything we can to improve upon that is going to be beneficial,” he said.

“I’d like to some kind of quantification, like how much of these type of foods need to be eaten to make a noticeable difference in diabetes and weight regulation, and is it possible to maybe get these type of naturally-found chemicals in a concentrated form so that it may be a supplement people can pay to help them,” he added.