People often say that “we are what we eat.” In recent years, this phrase has taken on a broader meaning thanks to studies on the relationship between the gut and the brain.


This connection does not depend solely on the foods you eat. It also involves the complex community of microorganisms that lives in your gut, known as the gut microbiota. Its composition may influence different processes in the body, although many questions still remain unanswered.


Prebiotics and memory during aging


A recent study found that certain prebiotic supplements may have a positive influence on the memory of older adults. The researchers highlighted two substances: inulin and fructooligosaccharides (FOS). Both are relatively affordable and easy to find.


These compounds are types of dietary fiber. Our bodies cannot digest them completely, so they reach the gut and serve as food for certain beneficial bacteria. For this reason, they are considered prebiotics.


You should not confuse them with probiotics. Probiotics contain live microorganisms, whereas prebiotics are substances that support the growth or activity of certain gut bacteria.


You can also find fiber in many foods. A less common example is quince, a high-fiber fruit that is not widely eaten. Even so, a whole food and a concentrated supplement are not equivalent, nor do they necessarily produce the same effects.


How the study involving twins over 60 was conducted


The research included 72 people, organized into 36 pairs of twins. Most were women, and all were over the age of 60.


The researchers randomly assigned each member of a twin pair to one of two groups. One twin received a daily powdered supplement containing prebiotic fibers and protein. The other received a placebo containing protein only.


Using twins made it possible to compare people with similar genetic backgrounds and early-life experiences. This helps control for some individual differences, although it does not eliminate every factor that may affect the results.


After 12 weeks, participants completed a memory assessment similar to tests used to detect early signs of Alzheimer’s disease.


What improvements were observed in memory


The twins who took the inulin or FOS supplement achieved better scores on the memory test than those who received the placebo. The finding drew interest because it suggests a potentially accessible way to support cognitive function during aging.


The team also investigated whether the supplement led to changes in strength or muscle mass. In this regard, it found no significant differences between the groups.


The findings were published in the scientific journal Nature Communications. However, this does not mean that inulin or FOS prevent Alzheimer’s disease, cure memory problems, or work in the same way for everyone.


This was a small, short-term study. Research involving more participants, more diverse groups, and longer follow-up periods will be needed to confirm the effect and understand its significance in everyday life.


How the gut microbiome and the brain are connected


The possible association between fiber supplements and cognitive function may be linked to their prebiotic action. During the study, changes were detected in the gut microbiota, including an increase in bacteria from the Bifidobacterium genus, which are considered beneficial in certain contexts.


These bacteria metabolize some types of fiber and produce compounds that may take part in metabolic, immune, and nervous system processes. This communication between the digestive system and the nervous system is commonly called the gut-brain axis.


The idea that the microbiome may influence different aspects of health is not new. Earlier research has also linked dietary changes or fasting methods with changes in the microbiota and in certain patterns of brain activity.


Even so, an association alone does not prove a direct cause-and-effect relationship. Scientists are still trying to understand which microorganisms are involved, which substances they produce, and how those signals might ultimately influence memory.


Is it advisable to take inulin or FOS supplements?


These results are promising, but they do not justify starting a supplement without considering your personal circumstances. Inulin and FOS can cause gas, bloating, or digestive discomfort, especially when consumed in high amounts or introduced suddenly.


If you have a digestive condition, take medication, or notice persistent changes in your memory, consult a healthcare professional. A proper assessment can help rule out sleep problems, stress, nutritional deficiencies, medication effects, or other causes that may also affect your ability to remember.


While science continues to investigate, you can care for your brain through habits that already have stronger evidence behind them: eating a varied diet, staying physically active, getting enough sleep, maintaining social connections, and stimulating your mind with activities you enjoy.


The microbiota opens up a fascinating path toward understanding aging. It does not offer magical solutions, but it does remind us of something valuable: brain health is also built through small everyday habits. 🧠