New research from King’s College London has found that taking a cheap, over-the-counter prebiotic supplement may enhance brain function in older adults.
This study— the first of its kind conducted on twins—showed that participants over 60 who took these supplements for just 12 weeks performed better on memory tests.
Even more intriguing? The same cognitive test used in the study is often employed to detect early signs of Alzheimer’s disease.
That means something as unassuming as a fiber supplement could play a significant role in staving off cognitive decline.
How Gut Health Influences the Brain
For years, researchers have been fascinated by the so-called gut-brain axis—the idea that our gut bacteria influence not just digestion but also mood, cognition, and even neurological health.
Prebiotics, the lesser-known relatives of probiotics, act as food for the beneficial bacteria in the gut, potentially improving their ability to support brain function.
The King’s College study focused on two specific prebiotics:
- Inulin – A dietary fiber found in many plants, particularly chicory root.
- Fructooligosaccharide (FOS) – A plant-based carbohydrate often used as a natural low-calorie sweetener.
These supplements are already widely available and cost just a few cents per dose—making them a remarkably accessible solution for brain health.
Twins Put to the Test
To eliminate genetic variables, the study recruited 36 pairs of identical twins over the age of 60.
Each pair was split, with one twin taking a daily dose of prebiotic-infused protein powder and the other consuming a placebo protein powder.
Neither the participants nor the researchers knew which twin received the actual supplement.
After three months, the twins who took the prebiotics scored higher on memory and learning tests compared to their placebo-taking siblings.
Additionally, stool samples indicated a noticeable increase in Bifidobacterium—a type of bacteria previously linked to better cognitive function in both animal and human studies.
A Challenge to Conventional Thinking
Most discussions about brain health center on medications, mental exercises, or lifestyle changes like sleep and exercise.
But this study suggests that the gut microbiome plays an even bigger role in cognition than previously thought.
We often hear that age-related cognitive decline is inevitable. But what if simple dietary changes could slow or even reverse some aspects of this decline?
Some scientists remain skeptical.
After all, correlation is not causation. Just because increased gut bacteria coincide with better memory scores doesn’t necessarily mean one causes the other.
However, previous studies on rodents have shown that manipulating gut bacteria can directly impact cognitive function.
The Unexpected Benefits of Prebiotics
Interestingly, while inulin and FOS boosted brain function, they didn’t have the same effect on muscle strength.
This challenges the notion that gut health interventions automatically improve all aspects of aging.
Still, researchers say the findings are promising.
“These plant fibers, which are cheap and available over the counter, could benefit a wide group of people in these cash-strapped times.
They are safe and acceptable too,” said Dr. Claire Steves, one of the study’s lead researchers.
The next step? Larger, longer-term studies to confirm whether these improvements persist over time and extend to other areas of health.
The Gut-Brain Connection: More Than Just a Theory
The idea that the gut influences the brain is not new.
Some researchers have gone so far as to call the gut our “second brain” due to its dense network of neurons and neurotransmitters.
But understanding exactly how the gut and brain communicate is still a work in progress.
Scientists theorize that gut bacteria influence the production of neurotransmitters like serotonin and dopamine, which play key roles in mood and cognition.
This means that maintaining a healthy gut may not just improve memory but could also help combat mental health issues like anxiety and depression.
Who Stands to Benefit Most?
While the study included both men and women, most participants were female.
This is important because women face a higher risk of developing Alzheimer’s disease than men.
If prebiotics prove to be an effective cognitive booster, they could offer a powerful, affordable intervention for those most at risk.
Additionally, for people already experiencing mild cognitive decline, adding a simple fiber supplement to their daily routine may provide a safe, low-cost way to potentially slow progression.
What This Means for the Future of Brain Health
This study opens the door to a new way of thinking about brain health: instead of relying solely on medications or complex interventions, perhaps the best strategy is to start with the gut.
While prebiotics are not a cure-all, they represent a simple, inexpensive tool that could complement other brain-boosting strategies like exercise, sleep, and cognitive training.
What You Can Do Today
- Consider adding prebiotics to your diet – Inulin and FOS supplements are widely available and inexpensive.
- Eat more fiber-rich foods – Foods like onions, garlic, bananas, and asparagus naturally contain prebiotics.
- Prioritize gut health – A well-balanced gut microbiome supports not just digestion but also brain function.
- Stay informed – As research continues, keep an eye on new findings about the gut-brain connection.
Final Thoughts
For years, brain health has been seen as separate from gut health. But research like this challenges that assumption.
If something as simple as a daily prebiotic supplement can help keep our minds sharp, it might be time to rethink how we approach aging.
The next time you’re in the supplement aisle, that inexpensive fiber supplement may be worth a second look.
