Dietary Fiber's Hidden Benefits: Experts Reveal How It Stabilizes Sugar and Lowers Cholesterol

Dietary fiber is often associated primarily with aiding bowel movements, but its functions extend far beyond that, according to nutritionist Yang Ssu-han. She explains that fiber broadly divides into two types: soluble and insoluble, each playing a crucial role in maintaining bodily functions.

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When you mention dietary fiber, many people's first thought is helping with bowel movements, but dietary fiber is not just one type.

Soluble fiber, which dissolves in water, offers a range of health advantages. It absorbs water to swell, not only facilitating easier bowel movements but also significantly contributing to stabilizing blood sugar levels, enhancing feelings of fullness, and reducing cholesterol. This type of fiber forms a gel-like substance in the digestive tract, which can slow down the emptying of the stomach and the absorption of carbohydrates, thereby mitigating rapid post-meal blood sugar spikes. This makes it a valuable dietary adjustment for individuals managing diabetes or seeking better blood sugar control.

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Soluble fiber absorbs water and increases in volume, helping to prolong satiety and reduce hunger between meals.

Common sources of soluble fiber include beta-glucans found in oats and barley, pectin in fruits, inulin in onions and burdock root, and mucilage in chia seeds, flax seeds, and psyllium. Yang emphasizes that incorporating whole grains, legumes, vegetables, fruits, and nuts into one's diet can easily increase soluble fiber intake. For instance, starting the day with unsweetened oatmeal mixed with yogurt, chia seeds, and fruit can provide a more sustained sense of fullness compared to refined carbohydrate options like white toast.

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It can increase the viscosity of food in the gastrointestinal tract, delaying gastric emptying and the speed of carbohydrate digestion and absorption.

Beyond blood sugar management and satiety, soluble fiber plays a role in lowering cholesterol. Specifically, beta-glucans in oats and barley have been extensively studied for their ability to bind to bile acids in the intestine, prompting the liver to use more cholesterol to produce new bile acids. This process helps reduce levels of LDL, or "bad" cholesterol. Furthermore, some soluble fibers act as prebiotics, feeding beneficial gut bacteria. These bacteria ferment the fiber, producing short-chain fatty acids that support the health of the intestinal lining. While beneficial, individuals new to high-fiber diets should increase intake gradually to avoid potential bloating or gas.

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It can bind to bile acids in the intestine, prompting the liver to use more cholesterol to produce new bile acids, thereby helping to lower low-density lipoprotein cholesterol, commonly known as bad cholesterol.