Eating a high-fiber diet may help lower dementia risk, study finds

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Scientists from the University of Tsukuba have discovered that consuming a high-fiber diet may be associated with a reduced risk of developing dementia.

Dietary fiber, found in plant foods, has numerous health benefits, including aiding in digestion and lowering the risk of certain diseases.

Understanding Dietary Fiber

Dietary fiber, also known as roughage, is the indigestible part of plant foods. There are two types of fiber: soluble and insoluble.

Soluble fiber absorbs water and helps slow down digestion, while insoluble fiber adds bulk to stool and aids in its passage through the digestive system.

Both types of fiber are important and can be found in various plant-based foods.

Exploring the Link Between Fiber and Dementia Risk

Previous studies have suggested that dietary fiber might play a role in preventing dementia, but limited scientific evidence exists.

In this study, researchers aimed to investigate whether a high-fiber diet is associated with a lower risk of dementia.

Study Details

The study involved 3,739 Japanese participants aged 40 to 64 years. The researchers estimated their dietary fiber intake using a 24-hour dietary recall method.

The participants were followed up from 1999 to 2020 to track dementia incidence. Dementia cases were further categorized into those with or without a history of stroke.

Findings and Results

Over the 20-year follow-up period, a total of 670 cases of dementia were identified. Importantly, the study found that higher dietary fiber intake was linked to a lower risk of dementia.

The effect was more pronounced for soluble fiber intake and was specifically observed in cases of dementia without a history of stroke.

The researchers also noted a similar association with fiber-containing foods, particularly potatoes, but not with vegetables or fruits.

Possible Mechanisms

The study authors suggest that soluble fiber may influence the composition of gut bacteria, which in turn could affect neuroinflammation—a factor in the onset of dementia.

Additionally, dietary fiber may help reduce other risk factors for dementia, including body weight, blood pressure, lipid levels, and glucose levels.


Consuming a high-fiber diet, especially one rich in soluble fiber, appears to be associated with a lower risk of developing dementia, according to this study.

Incorporating fiber-rich foods into one’s daily diet, such as potatoes, may have potential benefits for brain health.

However, further research is needed to better understand the precise mechanisms behind this association and to explore its applicability to other populations.

The research, conducted by Kazumasa Yamagishi et al., was published in the journal Nutritional Neuroscience.

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