Not Just For Constipation: The Magical Role of Fiber

Why does the gut need fiber？

The body lacks enzymes that can directly process complex carbohydrates. Thus, gut bacteria do the job of metabolizing fibers into short-chain fatty acids (SCFA) through anaerobic fermentation. Fibers become crucial food sources for the microbiome, while SCFAs have health benefits, including the regulation of cytokine secretion that causes gut inflammation or decreasing insulin resistance in obese patients. SCFAs also undergo oxidation to become bicarbonate, which is used to stratify the mucus and control pH levels to form a stable microbial environment.

What are the consequences of not enough fiber?

There’s a more complex argument than simply blaming high fat/sugar Western diets for damaging the digestive system. A 2020 study found that the lack of soluble fiber had a more significant effect in affecting the microbiome diversity and weight of both male & female mice than the food’s fat content. If bacteria do not have enough fiber as an energy source, they will begin feeding off glycoproteins secreted by the mucus, thus eroding it to create inflammation and pathogen infection.

Why not just supplements/a salad every day?

The market is currently saturated with a dizzying array of prebiotics and salads. However, the repetitiveness of eating a green leaf bowl means that a lack of diverse fibers is actually being absorbed. For example, there are 6 different types of widely accepted prebiotics such as inulin, and many more forms of potentially beneficial fibers like seaweed polysaccharides (4). Each might have a specific role in promoting a certain type of bacterial growth, meaning the quality of nutrients should be valued over quantity. To ensure healthy fiber intake, we can use the “ABC Rule.” Instead of considering calories, we should “Always Be Counting” the NUMBER of fruits and vegetables eaten per week, ideally around 20-30 unique types.