Forgetting things lately? According to new research, adding a daily fiber supplement may help improve brain function in adults over age 60 in as little as 12 weeks.
The results of a new placebo-controlled, randomized controlled trial published in Nature Communications suggest supplementing prebiotic fiber is an inexpensive and straightforward way to improve vital brain function, whose decline is associated with Alzheimer’s disease.
According to the Alzheimer’s Association, more than 6 million Americans live with Alzheimer’s disease. The number is projected to rise to nearly 13 million Americans by 2050. Almost one in three seniors die from Alzheimer’s or another form of dementia, meaning it takes the lives of more people than breast and prostate cancers combined. At the end of 2023, the disease cost the U.S. economy $345 billion.
In this double-blinded study, researchers from King’s College London in the United Kingdom enrolled 36 pairs of twins over the age of 60. The average age of the participants was 73, and 78 percent were female. One twin received a 7.5-gram prebiotic supplement daily for 12 weeks; the other received a placebo. Prebiotic fiber supplements encourage the growth of good bacteria that naturally exist in the gut. In contrast to probiotics, which are live microorganisms, prebiotics “feed” the good bacteria in the gut. In addition to receiving the supplement or placebo, participants also engaged in resistance exercises and ate a protein supplement to promote muscle functioning.
While the prebiotic supplement did not improve muscle function or strength, it did change the gut microbiome of those who took it. In particular, the amount of beneficial bacteria like Bifidobacterium increased significantly. Scientists believe that Bifidobacteria are among the first to colonize the human gastrointestinal tract. Because of their metabolic abilities, such as reducing oxidative stress, correcting cholesterol metabolism, and boosting immunity, Bifidobacteria are also believed to benefit heart health.
The research team noted there is “a growing body of evidence supporting a gut-brain axis,” in which the composition of the gut can directly influence how well the mind works. In particular, Bifidobacterium has been studied numerous times and has demonstrated encouraging effects on cognition, though more research is needed, the team wrote.
Furthermore, those given the fiber supplement performed better in the Paired Associates Learning Test, a standard medical test that assesses visual memory and new learning and is also used to detect early markers of Alzheimer’s disease.
‘Cheap and Readily Available’ Supplements to the Rescue?
“Our results demonstrate that cheap and readily available gut microbiome interventions hold promise for improving cognitive frailty in our ageing population,” the researchers wrote.
Prebiotic fiber supplements are relatively common varieties of over-the-counter fiber supplements offered in pharmacies, drugstores, and supermarkets.
Eating foods high in fiber could also be an easy and inexpensive way to lower one’s risk of dementia. A 2022 Japanese study involving about 3,700 adults between the ages of 40 and 64 found that rates of dementia were lowest among those who ate the most fiber. Those who ate the least daily fiber—on average, 8 grams a day—had the highest risk of dementia.
U.S. 2020–2025 Dietary Guidelines recommend adult women consume between 22 and 28 grams of fiber per day and adult men consume between 28 and 34 grams per day, depending on age. According to the guidelines, more than 90 percent of women and 97 percent of men do not get the recommended daily fiber. Fiber can be found naturally in avocados, oats, berries, artichokes, beans, lentils, quinoa, popcorn, almonds, chia seeds, pistachios, sunflower seeds, and dark chocolate.