Although compelling evidence from observational studies supports a positive association between consumption of cereal fiber and cardiovascular disease (CVD) risk reduction, randomized clinical trials (RCT)s often target viscous fiber type as the prospective contributor to lipid lowering to reduce CVD risk. The objective of our study is to compare the lipids lowering effects of viscous dietary fiber to non-viscous, cereal-type fiber in clinical studies. RCTs that evaluated the effect of viscous dietary fiber compared to non-viscous, cereal fiber on LDL cholesterol and alternative lipid markers, with duration of ≥ 3 weeks, in adults with or without hypercholesterolemia were included. Medline, EMBASE, CINAHL, and the Cochrane Central Register were searched through October 19, 2021. Data was extracted and assessed by 2 independent reviewers. The generic inverse variance method with random effects model was utilized to pool the data which were expressed as mean differences (MD)s with 95% confidence intervals (CI). Eighty-nine trials met eligibility criteria (n = 4755). Mean differences for the effect of viscous dietary fiber compared to non-viscous cereal fiber were: LDL cholesterol (MD = –0.26 mmol/L; 95% CI: –0.30, -0.22 mmol/L; P < 0.01), non-HDL cholesterol (MD = –0.33 mmol/L; 95% CI: –0.39, -0.28 mmol/L; P < 0.01), and Apo-B (MD = –0.04 g/L; 95% CI: –0.06, -0.03 g/L; P < 0.01). Viscous dietary fiber reduces LDL cholesterol and alternative lipid markers relative to the fiber from cereal sources, hence may be a preferred type of fiber-based dietary intervention targeting cardiovascular disease risk reduction.

Compressible mixing layer instabilities are of importance to a wide range of environmental and industrial applications. Past studies have focused on either ideal-gas or real-fluid thermodynamic regimes of single-species mixing layers. However, mixing layers of binary mixtures at supercritical conditions, commonly encountered in fuel injection systems, introduce additional complexities due to the added compositional degree-of-freedom. Moreover, the effect of strong variations in thermodynamic response functions across the Widom line on the binary mixing layer stability remains poorly understood. Thus, the objective of this study is to examine the coupling between the hydrodynamic instability and the real-fluid thermodynamics across the Widom line and its effects on the overall binary mixing layer dynamics. To this end, we develop a linear stability analysis of the full binary-species compressible transport equations coupled with the PC-SAFT equation of state. Analysis shows the existence of a novel instability mechanism that arises from juxtapositioning of the Widom-line transition and the hydrodynamic inflection point. This novel thermodynamically induced instability mechanism has the net effect of destabilizing the binary mixing layer at lowering supercritical conditions towards the critical pressure point. This is in contrast to previous stability analyses of supercritical single-species mixing layers, where increasing pressure destabilizes the flow due to its effect on reducing the density stratification. The discovered thermodynamically induced instability mechanism of binary mixing flows highlights the need for an extension of classical instability criteria to incorporate the effect of strong variations in the thermodynamic response functions across the Widom line on mixing layer instability.