Most adults worldwide don’t get enough fiber. Science Focus reports that experts think this shortfall may be contributing to high dementia rates.
Researchers suggest that a lack of fiber accelerates brain aging. This nutritional shortfall may help explain why dementia, particularly its most common form—Alzheimer’s disease—ranks among the leading causes of death in many countries.
This perspective is shared by dietitians Emily Liming and Kimberly Wilson, who presented their theory at a recent science festival in Cheltenham, England.
Insights from the Researchers
Liming and Wilson say fiber deficiency is a risk factor for developing dementia. For optimal health, adults should get at least 30 grams of fiber daily. However, most people manage only about 15 to 19 grams.
Several factors likely explain this gap. A 2023 report from the charity The Food Foundation found that healthy foods, such as fiber-rich fruits and vegetables, cost about twice as much as less healthy, low-fiber options. The report’s authors also found that about 60 percent of modern diets are made up of ultra-processed foods.
How Does Fiber Protect the Brain?
Wilson called fiber “one of the underrated protectors of the brain.” When gut microbes break down fiber, they produce short-chain fatty acids. These acids support the intestinal lining and can enter the bloodstream, reaching the brain. That means they can cross the blood-brain barrier, the structure that controls what gets into the brain.
Short-chain fatty acids help protect the blood-brain barrier, preventing toxic substances from getting into the brain.
How to Overcome Fiber Deficiency?
Liming says fiber is essential for gut health. It helps us feel fuller and more satisfied. Fiber also helps regulate blood sugar levels and blood pressure. The short-chain fatty acids that support brain health help fight inflammation.
Experts Recommend:
- Add fiber-rich foods such as rye bread and beans.
- Snack on a handful of nuts daily or add a mix of nuts and seeds to breakfast.
- Fill half your plate with vegetables.
- Choose 85% dark chocolate when craving something sweet; it contains about 11 grams of fiber per 100 grams.
- Keep the skin on potatoes and root vegetables like carrots and parsnips when cooking and eating.
Increasing your fiber intake is linked to a lower risk of colorectal cancer, type II diabetes, and heart disease. Fiber also helps us feel healthier and more energetic. Liming concluded that it nourishes the gut microbiome, which is crucial for overall health.
