Whole Wheat and Triticale Flours with Differing Viscosities Stimulate Cecal Fermentations and Lower Plasma and Hepatic Lipids in Rats

Abstract

Whole flours from oat, rye or barley effectively modify digestive fermentation and lipid metabolism, whereas the effectiveness of whole wheat flour has not been established. To address this question, cecal digestion, short-chain fatty acid (SCFA) metabolism and cholesterol metabolism were investigated in four groups of rats fed the following semipurified diets differing in their carbohydrate source: a control diet (purified wheat starch) and three whole cereal flour diets [Valoris wheat (Wv), Soissons wheat (Ws), or Carnac triticale (Tc)]. Wv is particularly viscous and rich in arabinoxylans, and Tc is richer in hemicellulose than wheat. Compared with controls, rats fed the whole-flour diets had enlarged ceca and a moderate acidification of the bulk pH ( approximately 6.4). In these rats, the cecal SCFA pool size was enhanced (P < 0.05), and the SCFA molar ratio reflected propionic/butyric acid-rich fermentations, especially in those fed TC: The portal SCFA concentrations reflected the rise of the acetic and propionic acid pools in the cecum, whereas portal butyric acid remained relatively low, probably reflecting extensive metabolism by the cecal wall. The fecal excretion of total steroids (bile acids + sterols) was markedly enhanced by all of the whole-flour diets, with Wv (+78%) > Tc (+64%) > Ws (+47%). In parallel, there was a significant plasma cholesterol-lowering effect for rats fed Wv (-27%) and Tc (-32%) and a plasma triglyceride-lowering effect (approximately -40%) in all rats fed whole-flour diets (P < 0.05). This effect was observed mainly for triglyceride-rich lipoprotein-cholesterol, whereas HDL cholesterol was unaffected. These results indicate that whole wheat flours can strikingly affect cecal SCFA, especially butyrate, and are effective plasma cholesterol-lowering agents.

Tartary Buckwheat Sprout Powder Lowers Plasma Cholesterol Level in Rats

“…Although little information on the hypocholesterolemic effects of vegetable sprouts is available, Taniguchi et al (12) recently reported that the radish sprout had a hypocholesterolemic effect in rats. They suggested that the effect might be due to the dietary fiber content in sprout powder (12), since dietary fiber is well known to decrease blood cholesterol in rats (27,28). The hypocholesterolemic effect of dietary fiber is mainly explained by the greater fecal steroid excretion (26,28,29).…”

Ingestion of Gelatinized Potato Starch Containing a High Level of Phosphorus Decreases Serum and Liver Lipids in Rats

“…It has been reported that propionate may be involved in lowering plasma cholesterol concentration in cholesterol-fed rats 25) . Furthermore, elevation of cecal SCFA level by dietary fiber is closely correlated with the decrease in plasma cholesterol level in rats fed a cholesterol-free or cholesterol-added diet [26][27][28] . In the present study, we expected that oligosaccharides produced from the potato starch by enzymatic degradation would reach the cecum and induce cecal fermentation.…”

Polydextrose in Lipid Metabolism

“…While acetate is a substrate for sterol and fatty acid synthesis, propionate counteracts this by inhibiting acetate incorporation to serum lipids [41]. Propionate has been shown to to reduce the rate of cholesterol synthesis [87,90], to inhibit fatty acid synthesis [91], to decrease liver lipogenesis [92], and to decrease hepatic and plasma and serum cholesterol levels [93,94]. Propionate supplementation has been shown increase serum HDL cholesterol and triglyceride levels without effect on total cholesterol [92,95].…”