Increased Lifespan

Studies have shown a correlation between high fiber intake and a lower risk of all-cause mortality. One study found that people who consumed the most fiber were 19% less likely to die during the study period compared to those who consumed the least [2]. Another study found that for every 10 grams of fiber consumed, the risk of mortality was reduced by 10% 3. A large-scale study with over 3.5 million participants showed that those with the highest fiber intake had a 23% lower risk of death 4. These findings suggest that a fiber-rich diet can contribute to a longer and healthier life.

It is important to note that the source of fiber can influence its effect on mortality risk. Higher intakes of fiber from cereals, vegetables, or legumes were associated with an 8–16% lower risk of all-cause mortality 4. This highlights the importance of consuming a variety of fiber-rich foods for maximum benefit.

Furthermore, two recent studies have shown that while eating more dietary fiber improves life expectancy, food processing may remove these benefits 5.

Improved Gut Microbiome Diversity

The gut microbiome plays a crucial role in overall health, and a diverse fiber diet can significantly impact its composition. Fiber acts as a prebiotic, providing nourishment for beneficial gut bacteria 6. A plant-based diet high in fiber has been shown to increase the diversity of the gut microbiome 7. Studies have shown that increasing fiber intake can alter the gut microbiome, leading to an increase in fiber-degrading microbes like Bifidobacterium and Lactobacillus 8. A diverse gut microbiome is associated with better digestion, improved immune function, and a reduced risk of chronic diseases.

The lack of fiber intake in industrialized societies may have significant health consequences, including an increased risk of colorectal cancer, autoimmune diseases, and reduced vaccine efficacy 9. This highlights the urgency of increasing fiber consumption.

The influences of dietary fiber on different gut microbes are specific to the type of fiber consumed. For example, many long-chain types of fiber have been shown to enhance the abundance of Faecalibacterium, while resistant starch type 2 (RS2) has a specific effect on the proliferation of Ruminococcus 10.

Reduced Risk of Chronic Diseases

A diverse fiber diet has been linked to a lower risk of various chronic diseases, including:

• Cardiovascular Disease: Soluble fiber can help lower LDL cholesterol levels, reducing the risk of heart disease 6. Studies have shown that high fiber intake is associated with a lower risk of cardiovascular disease and related mortality 11. Fiber may also have other heart-health benefits, such as lowering blood pressure and reducing inflammation 13. In patients with hypertension and type 2 diabetes, a high-fiber diet combined with medical treatment can improve various cardiovascular risk factors 14. This emphasizes the importance of fiber in conjunction with medical care.
• Type 2 Diabetes: Fiber helps regulate blood sugar levels by slowing down the absorption of glucose 6. Studies have shown that a high-fiber diet can improve glycemic control and reduce the risk of developing type 2 diabetes 15. Recent research in Hispanic adults suggests that eating more dietary fiber may help prevent type 2 diabetes by promoting beneficial gut bacteria and substances produced during metabolism 16. This highlights the importance of considering ethnicity in fiber research.
• Colon Cancer: A high-fiber diet is generally linked with a lower risk of colorectal cancer 17. However, studies have been inconsistent in their findings regarding the protective effect of fiber against colon cancer 18. Fiber promotes bowel regularity and adds bulk to the stool, reducing the time that waste products spend in the colon 17. This can help protect against colon cancer. A minimum of 50 grams of fiber a day is needed to minimize colon cancer risk 19. Studies suggest that fiber may have protective effects at various stages of colon cancer development, starting early in the process 20.

Fiber and Overall Health

Beyond the specific benefits mentioned above, fiber plays a crucial role in overall health and well-being. It aids in digestion by adding bulk to the stool and promoting regular bowel movements. This can help prevent constipation and other digestive issues 17. Fiber also helps regulate blood sugar levels by slowing down the absorption of glucose into the bloodstream. This can be beneficial for people with diabetes or those at risk of developing the condition 17.

Finaly, fiber can help lower cholesterol levels by interfering with the absorption of cholesterol in the gut. This can contribute to a healthier cardiovascular system and reduce the risk of heart disease 21. Fiber also promotes gut health by nourishing beneficial bacteria in the gut. These bacteria play a vital role in digestion, immunity, and overall health 22.