If there were a simple, daily habit that could help keep your brain sharp as you age, would you do it?

According to a new study from researchers at King’s College London, adding one specific supplement to your daily routine could significantly improve memory and brain function—especially in older adults. And the best part? It’s not a pricey prescription drug or a high-tech device. It’s prebiotic fiber.

Yes, you read that right — fiber. But not just the kind you find in whole grains and veggies (although those are great too). This study focused on a prebiotic supplement, which feeds the beneficial bacteria in your gut. It turns out that your gut health may have much more to do with your brain health than we previously realized.

The Study That’s Turning Heads

In the 12-week study, 72 healthy adults between the ages of 60 and 85 were given either a placebo or a daily prebiotic supplement made from inulin and FOS (fructooligosaccharides)—two natural plant fibers that act as food for gut bacteria. Researchers then measured their cognitive performance using memory and brain function tests.

The results? Participants who took the daily fiber supplement showed significant improvements in memory, particularly in recall and learning speed, compared to those on the placebo. Some even performed better than people 20 years younger.

“We saw real, measurable changes in the participants’ ability to learn and remember,” said Dr. Mary Ni Lochlainn, the lead researcher on the study. “This kind of improvement is rare, especially from a simple dietary supplement.”

What’s the Gut Got to Do with It?

You might wonder, “What does my gut have to do with my brain?”

It turns out a lot. Your gut and brain are connected by what’s called the gut-brain axis, a communication network that links your digestive system with your central nervous system. When your gut is healthy—meaning it has a good balance of beneficial bacteria—it can help reduce inflammation and support the production of neurotransmitters like serotonin and dopamine.

Prebiotic fiber helps fuel these good bacteria, influencing everything from mood and focus to long-term brain health.

“This is one of the first clinical trials in humans to show that targeting the gut microbiome with prebiotics could improve memory in older adults,” notes the team at King’s College.

Could This Help Prevent Dementia?

While this study didn’t directly measure dementia prevention, experts are optimistic. Memory decline and slower cognitive processing are early signs of conditions like Alzheimer’s. If something as simple as a fiber supplement can improve memory in just 12 weeks, it opens the door for more research into how gut health might help delay or reduce dementia risk.

And the best part? Prebiotic supplements are generally safe, inexpensive, and widely available — meaning they could become a practical tool for supporting brain health as we age.

How to Try It for Yourself

If you’re curious about trying prebiotic supplements, look for ones that contain inulin and FOS, the same fibers used in the study. You can also increase your intake naturally through foods like onions, garlic, leeks, bananas, and asparagus. However, it may be tough to get the same dose shown in the study just through food.

The Takeaway

his study adds to a growing body of research showing that gut health is more than just digestion—it could be key to healthy aging and sharper memory. As Dr. Ni Lochlainn puts it, “Improving your gut microbiome might just be one of the easiest ways to support your brain.”

So next time you're shopping for supplements, you might think twice about skipping the fiber aisle—your future brain will thank you.

Want to give your gut (and brain) a boost? Zenwise offers several gut health formulas, including prebiotics to help feed your microbiome and support digestive wellness—like our best-selling Digestive Enzymes with Prebiotics + Probiotics.an easy, tasty way to support your gut-brain connection—without overthinking it.

Curious about what other Zenwise products feature prebiotics? Contact us seven days a week at support@zenwise.com or (800) 940-2972, M-F, from 9 a.m. to 5 p.m.