Many people looking to reduce their calorie intake are required to consume sugar-free beverages and foods. A new research suggests that the gut is much harder to fool than our taste buds.
The study based on previous findings, demonstrating that mice who lack the ability to taste, can still disclose calorific sugar solutions apart from sweetener or water, and still show preference for sugar.
These findings suggest that the mammalian gastrointestinal tract has a method of identifying sugar that exists south of the mouth. Researchers previously stated that when the small intestine is bypassed, this preference for sugar disappears, further narrowing the search. The latest study, published by a Duke University researcher, claims to have discovered the cells responsible for our guts sweet tooth.
The sugar-sensing cells
A specific type of cell in the gut called neuropod cells senses both sugar and non-caloric sweetener. According to Dr. Laura Rupprecht, a postdoctoral fellow in the Laboratory of Gut Brain Neurobiology at Duke Medicine, the neuropod cell synapses with nerves to direct an individual to select sugar instead of nutritive sweetener.
These neuropod cells were discovered by Rupprechts colleagues in 2018. They sit at a critical interface between the cells in our gut and our parasympathetic nervous system (PNS). The PNS is responsible for gathering information about a variety of bodily processes that can be roughly grouped into rest-and-digest behaviors. The vagus nerve, which connects our brain to our internal organs, is the most important part of the PNS.
According to Rupprecht, the neurons are positioned to drive these particular behaviors. Working as a team with material scientists at MIT, we developed a flexible fiber tool to control the neuropod cells using light.
Bringing light to the gut
The team bred mice who had a genetic alteration to their neuropod cells in the presence of a certain wavelength of light. Consequently, the optogenetic lights changed, indicating that the neuropod cells had the sugar signal.
The teams'' next objective was to determine whether sugar would be distinguished from sweetener. The research found that three populations of neuropods were found that they were activated as a result of sugar, some to sweetener, and others that expressed interest in these individuals. The authors found that these cells taste receptor cells in the tongue or retinal cone cells that assist the eye discern color.
Optogenetics is a technique, commonly used in neuromodulation, that gives researchers control over the activity of neurons or other cells or groups of cells. Animals are genetically modified so that some of their neurons express light-sensitive ion channels, which allows cell function to be switched on or off in response to light exposure.
While sugar stimulated the cells to release the neurotransmitter glutamate, the artificial sweetener sucralose did not prompt a release. The team studied both mouse and human gut cells and discovered that this glutamate response was similar in both, suggesting that the mouse mechanism is likely to be conserved in humans.
The researchers performed behavioral experiments in a small sample of mice. These showed that when their-light sensitive neuropods were turned off, the animals'' sugar preference was eliminated. However, after the laser light stimulation ended, their sugar affinity returned. In their paper discussions, they said that these animals did not lose their sucrose preference, rather their ability to discern the preferred sugar from the sweetener.
The big business of artificial sweeteners
These findings do not contain sole implications for sugar-loving mice. Artificial sweeteners are a big undertaking. In 2018, the carbonated beverage market in the United States had an estimated $8 billion, and Diet Coke alone had an estimated eight percent slice of that pie. It''s clear that the gut can see through the trick while bypassing the calories. However, Rupprechts finds that these findings may have implications for these beverages'' effectiveness in keeping us away from the calories.
In many situations, artificial sweeteners can help people lose weight and curb cravings, but in other situations, they have no impact on eating, according to Rupprecht. We can prove that artificial sweeteners signal to the brain, but do not direct behavior in the same way as caloric sugars. In short, artificial sweeteners might fool our taste neurons, but the cells that work out the hard math of the energy we consume are unconvinced by the illusion.
This is the latest edition of a series of studies that highlight excessive sugar and calories consumption. Current medications to help obese people who struggle with sugar intake may be a relatively inexpensive approach.