Summary: A new study found a new reason some people eat more sugar. People with a certain mutation lack free fatty acid receptor 4 (FFAR4). Their gut bacteria change. That shifts the gut-brain axis, and it shifts what they choose to eat.
Too much sugar does harm all over the body. Some experts say sugar addiction does more harm than ethanol addiction. Sugar does not bend the mind like alcohol or street drugs. But it does cause the signs of addiction, like strong cravings. It also acts on the brain’s reward pathways.
High sugar intake hits harder when you live with diabetes. It spikes blood glucose and feeds insulin resistance.
For a long time, researchers have tried to explain quieter addictions like sugar addiction. They have offered many theories. Some point to changes in the brain’s reward pathway. Some point to chemical changes in the brain. Certain metabolic changes may also play a role.
In recent years, though, the focus has moved to the gut. Science now knows the gut has more say over the brain than anyone thought. The gut-brain axis may play a big role in addiction to certain foods and sugars. Researchers also now think changes in gut bacteria may feed this addiction.
In one of the recent studies published in Nature Microbiology, researchers found a microbe that may help cut sugar intake.
The study used both mice with diabetes and 60 diabetes patients. Researchers tested their blood. Both the mice and the patients were low in free fatty acid receptor 4 (FFAR4). This was mainly due to an FFAR4 mutation.
People with the FFAR4 mutation craved more sugar. Low levels of this receptor also significantly cut the gut population of Bacteroides vulgatus and its key metabolite (the chemical it makes), pantothenic acid. Pantothenic acid turns on the GLP-1-FGF21 hormone axis. That axis helps control appetite and has wide effects on metabolism.
So researchers think three things drove the extra sugar cravings: this mutation, low pantothenic acid, and fewer Bacteroides vulgatus.
To test their idea, researchers gave Bacteroides vulgatus and pantothenic acid to the diabetic mice. The mice’s food choices changed. Researchers think they have found a new mechanism behind the taste for sugar.
So researchers propose that probiotics with this strain may help curb sugar addiction. They may also boost metabolic health and bring other benefits.
The gut’s role in the gut-brain axis is complex. Still, more and more studies show gut bacteria have more say in this axis than once thought.
Gut bacteria can change for many reasons. Genes, medications and food choices all play a part.
There are many ways to change gut bacteria, too. Probiotics are just one way. Lifestyle and diet changes are others.
Finally, many other mechanisms likely play a role in sugar addiction. Future research may find other microbes that affect metabolic health and the taste for sugar.
Frequently asked questions
Can gut bacteria cause sugar cravings?
Yes. In a Nature Microbiology study of diabetic mice and 60 people with diabetes, those low in the free fatty acid receptor FFAR4 craved more sugar. The shortfall shrank the gut population of Bacteroides vulgatus and its metabolite pantothenic acid. When researchers gave the mice that bacterium and pantothenic acid back, their food choices changed.
How does the gut tell the brain what to eat?
Through the gut-brain axis. Pantothenic acid made by Bacteroides vulgatus turns on the GLP-1–FGF21 hormone axis. That axis helps control appetite and has wide effects on metabolism. When the bacterium and its metabolite drop, the signal weakens and the taste for sugar rises. The gut has a bigger say over the brain than science once thought.
Will probiotics help with sugar cravings?
Researchers propose that probiotics with this strain may help rein in sugar addiction and boost metabolic health. Probiotics are only one lever. Gut bacteria also shift with genes, drugs and food choices. So lifestyle and diet changes are the other ways to reshape the gut bacteria behind the cravings.
Is sugar addictive?
Sugar does not bend the mind the way alcohol or street drugs do. But it produces the marks of addiction, including strong cravings. It also acts on the brain’s reward pathways. Some experts think sugar addiction does more harm than alcohol addiction. In diabetes the damage stacks up, because sugar drives glucose spikes and insulin resistance.
Source:
Zhang, T., Wang, W., Li, J., Ye, X., Wang, Z., Cui, S., Shen, S., Liang, X., Chen, Y. Q., & Zhu, S. (2025). Free fatty acid receptor 4 modulates dietary sugar preference via the gut microbiota. Nature Microbiology, 1–14. https://doi.org/10.1038/s41564-024-01902-8
Dr. Gurpreet Singh Padda, MD, MBA, MHP
