Optimizing Dietary Fiber Intake: Strategies for Human Nutrition and Food Science
This 2026 narrative review evaluated strategies to increase dietary fiber intake and reduce risk of noncommunicable chronic diseases (NCDs), including type 2 diabetes and cardiovascular disease. The authors compared five approaches: whole and minimally processed plant foods, processed whole-plant foods, processed foods with added plant ingredients, fiber-fortified foods, and fiber supplements. Evidence was drawn from human trials, systematic reviews, and mechanistic microbiome research.
The strongest and most consistent benefits were seen with diets rich in whole and minimally processed plant foods. These patterns were associated with reductions in low-density lipoprotein (LDL) cholesterol, blood pressure, systemic inflammation, and improved glycemic control. Whole-grain intake increased stool bulk and improved metabolic markers, while β-glucan from oats and barley lowered LDL cholesterol and inflammatory markers such as interleukin-6. Fiber-fortified foods and supplements showed more targeted and sometimes inconsistent effects. Viscous fibers such as psyllium reduced LDL cholesterol and blood pressure, while fermentable fibers like resistant starch improved insulin sensitivity and inflammatory markers. In contrast, highly purified fibers such as inulin produced mixed results, with some studies reporting increased inflammatory markers at higher doses (15–30 g/day).
The review emphasized that fiber structure and food matrix are critical. Intrinsic fiber within intact plant cell walls slows digestion and supports gradual fermentation across the colon, producing short-chain fatty acids that benefit metabolic and immune health. Isolated fibers often ferment more rapidly and lack the broader bioactive compounds found in whole foods. Microbiome responses were individualized, and compositional changes did not always translate into clinical benefit.
The authors conclude that whole-plant food strategies provide the most reliable protection against chronic disease, though population adherence remains low. Fiber-fortified foods and supplements may help close intake gaps, but their effects depend on fiber type, dose, and processing. Future research should clarify causal microbiome links, evaluate long-term safety of high-dose supplementation, and develop scalable strategies that preserve fiber structure.
Overall, this review reinforces that increasing fiber intake is foundational for chronic disease prevention, but how fiber is delivered strongly shapes its health impact.