Search terms were combined to find studies assessing the effect of potentially prebiotic carbohydrates on gut microbiota composition. Studies referred to in review articles published on the topic were also included in some cases. Only studies supplementing the diet of healthy individuals were included. Second, the microbiota genera that were found to be altered upon carbohydrate supplementation were then further investigated in a second literature search in which the name of the genera was combined with the search terms “correlation,” “health,” “obesity,” “diabetes,” “inflammation,” “cardio(-) metabolic disease,” and “cardio(-)vascular disease.” Again, studies referred to in review articles published on the topic were also included in some cases.
species level reported high levels of opportunistic pathogens like Clostridium hathewayi and Clostridium ramosum to be linked to T2DM (106), whereas high weight loss was associated with a decrease in Clostridium coccoides and histolyticum (121, 122). In addition, Clostridium difficile is well known for its infectious properties, as it is an important cause of diarrhea in hospitalized patients (123). Finally, the presence of Clostridium septicum is suspected to play a role in colorectal carcinogenesis (124).
Here, animal studies were included, in addition to human studies, because they can often be instrumental in explaining the health effects of the genera in the (sometimes scarce) human studies. Besides playing a role in fermentation and immune functioning, the diversity and abundance of gut microbiota also plays a role in regulation of body weight and energy balance (26-28). This notion started with the discovery of Turnbaugh and colleagues in 2006 showing that transplantation of gut microbiota of genetically obese ob/ob mice into the gut of germ-free mice resulted in greater weight gain of the receiving animals than animals that received the microbiota of their lean counterparts (29). Comparable studies have since then been done, all adding to the conclusion that obesity risk, as well as related cardiometabolic and inflammatory derangements may rely, at least in part, on gut microbiota (30-34). Because of the apparent fact that the relative abundance and diversity of gut microbiota is related to the host’s health and/or disease status (20, 35), the possibility to affect the composition of intestinal microbiota by complex indigestible carbohydrates-so-called “prebiotics”-and subsequently improve the health of the host (36) has gained a lot of interest over the past few years.
Propionate is a major glucose precursor in ruminant animals such as the cow and sheep, but this is not an important pathway in humans. Butyrate is metabolized primarily by colonocytes and has been shown to regulate cell growth, and to induce differentiation and apoptosis (66). -glucan, guar gum and those from psyllium have been repeatedly shown to lower serum cholesterol levels in those with elevated levels, with little change if serum levels are normal (63,64).
The term was coined largely to distinguish sugars from other carbohydrates and in the report denotes “fruit, vegetables and whole-grains”. The term has since come to be used to describe either starch alone, or the combination of all polysaccharides. It was used to encourage consumption of what were considered to be healthy foods such as whole-grain cereals, etc., but becomes meaningless when used to describe fruit and vegetables which are low in starch.
This paper examines the use of the defatted rice bran hemicellulose B (RBHB), and insoluble dietary fibre (RBDF), as two functional ingredients added to bakery products. The results show that the RBHB from defatted rice bran had high water-binding and swelling capacity.
The low abundance of Bifidobacteria in overweight adults and children, as well as in women gaining relatively much weight during pregnancy, has been reported in other studies as well (20, 101, 122, 130, 131). The inverse relation between Bifidobacteria abundance and diabetes was also found in a cohort study of 50 Chinese T2D patients compared to 30 healthy Chinese individuals (132).
- While there is general agreement that the non-starch polysaccharides are the principal part of dietary fibre there is currently no consensus as to whether other components should be included in this term.
- No significant alteration in pasta structure on CMC incorporation was observed by microscopy.
- Lignin, a noncarbohydrate polymer containing alcohols and acids, is a woody fiber found in wheat bran and the seeds of fruits and vegetables.
- Furthermore, conceptual aspects, such as definition, classification, and properties of dietary fiber and mainly characteristics about the micronization and extrusion processes, are reported.
- Like active transport, facilitated diffusion requires a specific carrier, but instead of needing energy, it relies on the low levels of fructose inside the cell to “pull” the fructose inside.
For example, through their effects on gastric motility and intestinal transit stimulation, SCFAs stimulate serotonin release as reported in an in vitro colonic mucosal system (47). Locally butyrate functions as an important energy source for colonocytes, and this interaction contributes to a reduction in the risk of colorectal cancer (4, 48). Butyrate also affects fuel fluxes and energy balance by stimulating leptin and glucagon-like peptide 1 amide (49). Butyrate has even been reported to elicit antidepressant effects in the mouse (50) and to stimulate social behavior and facilitating long-term memory consolidation and neuroprotection/regeneration (51, 52).
One of the three principal types of carbohydrate, along with starches and cellulose. Sugars can be defined as any of various water-soluble carbohydrates of varying sweetness.
the holding of water by the residual dietary fiber after fermentation. Food polymers may be soluble in and/or plasticized by water. Water is the most important plasticizer, particularly in biological systems thereby changing mechanical properties. The cells of cooked potatoes and legumes are gels filled with gelatinized starch granules.
Despite large differences in molecular structure, no major differences existed between the different types of water-soluble fiber, suggesting a common underlying mechanism. In this respect, it is most likely that water-soluble fibers lower the (re)absorption of in particular bile acids.
But if the carbohydrates are not quickly burned off, they eventually will be stored as fat. This is the case even with healthy carbohydrates, but the situation is much worse with junk-food carbohydrates, which offer only empty calories stripped of vitamin and mineral content. One example is a particular brand of candy bar that, over the years, has been promoted in commercials as a means of obtaining a quick burst of energy. In fact, this and all other white-sugar-based candies give only a quick “sugar high,” followed almost immediately by a.
Cellulose is a polysaccharide, made from units of glucose, that constitutes the principal part of the cell walls of plants and is found naturally in fibrous materials, such as cotton. Commercially, it is a raw material for such manufactured goods as paper, cellophane, and rayon. Resistant starch consists of the same type of starch molecules that can normally undergo digestion in your gut but instead remain resistant to the action of your digestive enzymes. Foods containing resistant starches include carbohydrate-rich vegetables and grains, such as potatoes or pasta, that have been allowed to cool after cooking. Raw cornstarch, sourdough bread and some unripe fruits also supply resistant starch to your diet.