When it comes to brain health, most people expect expensive pills or complex routines, but a recent study suggests that a simple and affordable supplement could offer noticeable benefits, especially for older adults. Researchers are now exploring how certain dietary fibers, long known for gut support, may also improve memory and thinking.

A twin study from King’s College London found that pairing protein powder with a simple prebiotic led to better memory scores in older adults. Let’s review the findings in more detail.

What the study found on prebiotics and brain health

In the study, 36 pairs of adults over age 60 were part of a randomized, double-blind trial. One twin in each pair took protein plus the prebiotic, while the other took protein with a placebo. After 12 weeks, those taking inulin or FOS performed better on memory and processing-speed tests often used to detect early cognitive decline.

The prebiotics also increased levels of beneficial gut bacteria like Bifidobacterium, reinforcing the link between gut health and brain health. Research suggests this group of bacteria supports cognitive health through the gut-brain axis. Meanwhile, there was no difference between groups in muscle strength or other physical benefits.

Experts say this is a promising and inexpensive way to support memory and thinking in older adults. The fact that benefits showed up in just 12 weeks and through a supplement your local pharmacy likely stocks is worth noting. That said, researchers caution that longer and broader trials are needed to confirm the specific effects across more people.

Tips and precautions for considering prebiotics

Adding inulin or FOS supplements to a routine may be worth it, but take into account the following tips to approach them wisely:

Talk to your doctor: If you have digestive issues, kidney disease, or take multiple medications, check with your provider before starting supplements. In any case, it’s good to consult an expert before taking any new supplements.
Choose a standard dose: Don’t exceed recommended amounts unless advised by a physician.
Start low and go slow: If you’re new to prebiotics, begin with a small dose and increase gradually. This helps your gut adjust and may reduce gas or bloating.
Prioritize food first: Whole foods like onions, leeks, wheat, legumes, and chicory root naturally contain prebiotics and fiber. Supplements are not meant to replace healthy eating.
Think long term: Effects were measured after three months, and only for cognition. There’s no guarantee the memory boost persists without continued use or with other health changes.

The results are encouraging: combining protein and a basic prebiotic, like inulin or FOS, may help sharpen memory and slow cognitive decline in people over 60. These plant fibers are low-cost, widely available, and generally well tolerated. Still, supplements are most effective when they fit into a balanced diet and healthy routine.

It’s not a cure-all—and it didn’t improve muscle strength—but it supports emerging science linking gut health to brain health. For many seniors, it’s a practice worth exploring, especially when paired with nutritious meals and lifestyle habits that support longevity and mental clarity.