Dr. Chang Chia-ming, director of the Department of Genetics and Eugenics at Taipei Veterans General Hospital, Taiwan (China), states that many everyday foods have a characteristic moist, sticky, and slippery texture. These foods provide the gut with an essential nutrient: soluble fiber. This is a primary energy source for gut microbiota and activates the body's self-healing mechanisms.

According to the expert, soluble fiber is the core key to gut health. Ingredients such as okra, yam, wood ear mushrooms, kelp, and seaweed offer a soft, succulent, and slippery sensation when consumed, thanks to their rich soluble fiber content.

Dr. Chang Chia-ming explains that soluble fiber is primarily composed of pectin, plant gums, mucopolysaccharides, beta-glucans, and resistant oligosaccharides. These molecules strongly absorb water to form a gel-like structure, moving slowly and remaining in the intestines for an extended period, thus becoming a vital nutrient source for gut microbiota.

The human body cannot digest soluble fiber on its own, but beneficial gut bacteria can convert it into short-chain fatty acids, a group of signaling molecules that directly impact overall health. Among these, acetic, propionic, and butyric acids are the most important active compounds.

Illustration: Cleveland Clinic

Butyric acid, in particular, is not only the main nutrient for colon cells but also has the ability to intervene and "turn off" inflammation-causing gene that have been activated for a long time. By blocking harmful enzymes and promoting immune cells to function correctly, this active compound helps relieve pressure on the immune system and enables the body to heal itself from within.

After consuming foods rich in soluble fiber, appetite significantly decreases. This change is not due to willpower to suppress hunger but because the gut begins to send normal signals.

Specifically, short-chain fatty acids activate G protein-coupled receptors (GPCRs), prompting the gut to secrete natural satiety hormones like GLP-1 and peptide YY. These are core signals the body uses to regulate appetite, stabilize blood sugar, and control the rate of gastric emptying. Through this mechanism, gastric digestion slows down, helping blood sugar levels remain balanced and promoting a more natural feeling of fullness.

Conversely, if the body lacks soluble fiber for an extended period, gut bacteria are forced to consume protein and the intestinal mucous layer. This process produces toxins such as ammonia, amines, branched-chain fatty acids, and excessive secondary bile acids. Over time, the intestinal protective barrier thins, causing inflammatory signals to spread uncontrollably. This negative chain reaction is the root cause of insulin resistance, fatty liver disease, irritable bowel syndrome, and even colorectal cancer.

Dr. Chang advises people to gradually increase their daily soluble fiber intake to allow gut bacteria sufficient time to adapt, avoiding sudden changes that can cause bloating. Additionally, daily meals should vary continuously by rotating fiber sources from green vegetables, legumes, various mushrooms, and seaweed, rather than sticking to one type. Particularly, prioritize consuming whole, unprocessed foods instead of over-relying on refined, packaged fiber powders in the long term.

Binh Minh (According to TVBS)