Indigestible facts: How dietary fiber can prevent dementia
A new long-term study from Japan provides promising evidence that a high-fiber diet can reduce the risk of dementia. Soluble fiber in particular appears to have a protective effect, as the study published in Nutritional Neuroscience suggests.
To investigate this connection, researchers from the University of Tsukuba and other Japanese institutes analyzed the eating habits of almost 4,000 Japanese aged between 40 and 64 over a period of 19 years. The focus was on the intake of dietary fiber, which was determined with the help of 24-hour dietary protocols. These logs record all food and drink consumed over the last 24 hours, the nutrient composition of which is then analyzed in detail using a special program. In this study, the focus was particularly on high-fiber foods such as potatoes, vegetables and fruit [1].
Study results
During the observation period, 670 participants developed severe dementia that required extensive care for several or all daily activities.
To investigate the influence of fiber intake, the researchers divided the participants into four groups, from the lowest to the highest fiber intake. The people with the lowest intake consumed an average of 8.9 g of fiber per day, the second highest group 12.3 g. In the third group, the daily intake was 15.6 g, and the people with the highest intake averaged 21.4 g of fiber per day. The analysis of the data showed that people with the highest fiber intake (21.4 g per day) had a 26 percent lower risk of developing dementia than people in the group with the lowest fiber intake. This protective effect was particularly pronounced with soluble fiber. It should be noted that even the group with the highest fiber intake did not reach the actual recommendations of more than 30 g/day.
An interesting aspect of the study was that the consumption of potatoes, which are also rich in fiber, was associated with a lower risk of dementia. Other high-fiber foods such as vegetables and fruit did not show this effect. The researchers suspect that this could be due to the different composition of starch in potatoes compared to vegetables and fruit [1].
Mechanism of the effect of dietary fiber in the prevention of dementia
The positive effects of dietary fiber on the risk of dementia suggest that soluble fiber in particular could play a decisive role in prevention. One possible explanation for this lies in their positive influence on the intestinal flora: soluble fiber promotes the growth of certain types of bacteria that produce short-chain fatty acids such as butyrate. These fatty acids have anti-inflammatory properties and could have a neuroprotective effect by protecting the brain from harmful processes [1].
Conclusion:
Although more research is needed to understand the exact mechanisms, the findings suggest that a diet high in fiber, particularly soluble fiber, could be a simple and effective way to reduce the risk of dementia. Including foods such as oatmeal, pulses, apples, pears and potatoes in your daily diet could not only aid digestion, but also protect your brain [1].
References
- Yamagishi, K., Maruyama, K., Ikeda, A., Nagao, M., Noda, H., Umesawa, M., Hayama-Terada, M., Muraki, I., Okada, C., Tanaka, M., Kishida, R., Kihara, T., Ohira, T., Imano, H., Brunner, E. J., Sankai, T., Okada, T., Tanigawa, T., Kitamura, A., … Iso, H. (2023). Dietary fiber intake and risk of incident disabling dementia: The Circulatory Risk in Communities Study. Nutritional Neuroscience, 26(2), 148-155. https://doi.org/10.1080/1028415X.2022.2027592
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