برچسب: fibers

Not all fibers have the same efficacy and structural characteristics. There are short-chain (oligofructose) and long-chain (polyfructose, such as inulin) fructans typically present in the plant roots where they are used as energy pools.

Among the plant-derived beneficial fibers, glucomannan (KJM), extracted traditionally from the tuber root of Amorphophallus konjac, has been used for centuries in Asia as a food source and beneficial healthy remedy.

Several metanalyses of large clinical trials  confirmed that KJM can safely and effectively be used for cardiovascular diseases (CVD) risk reduction, reduction of LDL cholesterol (about 20% total reduction) and non-HDL cholesterol (almost 20-30% reduction) both in adults and children at all doses of KJM used (2.0-15.1 g/d). Several early and more recent investigations have also shown that supplements containing glucomannan, as stated claim promoted weight loss and reduction of postprandial glycemia.

Another oligosaccharide with interesting activity and sufficient body of good quality literature is inulin. Even if inulin has not obtained an official claim for weight-loss management, recent meta-analyses of randomized clinical trials that tested the effect of inulin-type fructans on serum triacylglycerols and other dysmetabolic parameters showed that the intake of inulin or oligofructose was associated with a significant decrease (about 20 mmol/L) in serum triacylglycerol concentrations in the vast majority of clinical trials (>80% of trials).

Moreover, because inulin fibers are not absorbed in the small bowel, they have no effect on post- prandial blood glycaemia and, at the same time, their low-glycemic-index minimally stimulates cholesterol synthesis, thus lowering cholesterol blood concentrations.

Of note, short chain fatty acids (SCFA) produced during colon fermentation of inulin or galactomannan fibers that reach the colon almost unaltered, specifically bind a series of orphan G protein-coupled receptors. In particular, the free fatty acid receptor 3 (FFA3/GPR41) that is expressed both in the intestine and sympathetic nervous system, recognize SCFA including propionate and butyrate, that trigger several folds higher receptor activation compared to acetate.

Figure 1. The biological mechanisms by which prebiotics exert their health effects

The biological mechanisms by which prebiotics exert their health effects

• Highly viscous soluble fibers exert their activity in different districts of the gastrointestina
• l tract and can affect host physiology and gut barrier function directly or indirectly.
• Delay gastric emptying, thereby affecting nutrient kinetics and satiety.
• Enhance intestinal viscosity, that impairing the uptake of dietary cholesterol and reducing bile acids reabsorption.
• Increase bacterial fermentation in the colon and promote beneficial bacteria replication and metabolic production of SCFA thus increasing the molar ratio of propionate to acetate, that affect gut barrier integrity and cholesterol metabolism.
• Inhibit or down-regulate liver lipogenic pathways through propionic acid production.
• SCFA production reduced translocation of Gram-negative bacteria derived Lipopolysaccharide (LPS) systemic metaflammation both in human and animal models.
• SCFA production affects the secretion of gastrointestinal hormones such as regulation of incretin hormone GLP-1  and other gastrointestinal peptides (the PYY satiety hormone for example).

Reference

Ferrarese R, Ceresola ER, Preti A, Canducci F. Probiotics, prebiotics and synbiotics for weight loss and metabolic syndrome in the microbiome era. Eur Rev Med Pharmacol Sci. 2018 Nov;22(21):7588-7605. doi: 10.26355/eurrev_201811_16301. PMID: 30468509.

gut microbiota