Polysaccharides derived from plant foods are major components of the human diet, with limited contributions of related components from fungal and algal sources. In particular, starch and other storage carbohydrates are the major sources of energy in all diets, while cell wall polysaccharides are the major components of dietary fiber. We review the role of these components in the human diet, including their structure and distribution, their modification during food processing and effects on functional properties, their behavior in the gastrointestinal tract, and their contribution to healthy diets.

Our study suggests that a 5-week high dietary fiber intake of oat bran, rye bran, and sugar beet fiber might reduce the low-grade inflammatory response measured as CRP which could, together with reduced fibrinogen, help to prevent the risk of cardiovascular disease.

The present review examines the evidence regarding the effect of β‐glucan on variables linked to the metabolic syndrome (MetS), including appetite control, glucose control, hypertension, and gut microbiota composition. Appetite control can indirectly influence MetS by inducing a decreased energy intake, and promising results for a β‐glucan intake to decrease appetite have been found using gut hormone responses and subjective appetite indicators. Beta‐glucan also improves the glycemic index of meals and beneficially influences glucose metabolism in patients with type 2 diabetes or MetS, as well as in healthy subjects. Furthermore, a blood‐pressure‐lowering effect of β‐glucan in hypertensive subjects seems fairly well substantiated. The gut microbiota composition might be an interesting target to prevent MetS, and preliminary results indicate the prebiotic potential of β‐glucan. The evidence that β‐glucan influences appetite control and gut microbiota in a positive way is still insufficient or difficult to interpret, and additional studies are needed in this field. Still, much evidence indicates that increased β‐glucan intake could prevent MetS. Such evidence should encourage increased efforts toward the development of β‐glucan‐containing functional foods and promote the intake of β‐glucan‐rich foods, with the aim of reducing healthcare costs and disease prevalence.

The objective was to investigate the alterations of plasma metabolome profiles to identify exposure and effect markers of dietary fiber intake. Subjects (n = 25) aged 58.6 (1.1) years (mean and SD) with a body mass index of 26.6 (0.5) kg/m(2) were given a high fiber (HF) and a low fiber (LF) diet, in a 5-week randomized controlled crossover intervention. The HF diet consisted of oat bran, rye bran, and sugar beet fiber incorporated into test food products, whereas the LF diet was made of equivalent food products to the HF diet, but without adding fibers. Blood plasma samples were collected at the start and end of each intervention period and analyzed by LC-QTOF/MS. In total, 6 features in positive mode and 14 features in negative mode were significantly different between the HF and the LF diet (p < 0.01, q < 0.05). Two markers, 2,6-dihydroxybenzoic acid and 2-aminophenol sulfate, were increased after HF diet, along with a tentatively identified saponin derived from oat avenacosides. The untargeted metabolomics approach enabled the identification of two new markers of dietary fiber intake in human plasma. Further studies will be needed to verify if these markers could serve as compliance markers of fiber intake.

Postprandial glucose, insulin and triglyceride concentrations are influenced by dietary fibre-rich meals, depending on fibre source, dose of soluble and total fibre and possibly gender.