Wheat alkylresorcinol increases fecal lipid excretion and suppresses feed efficiency in mice depending on time of supplementation.

OBJECTIVE: The regular consumption of whole grains is linked to a lower likelihood of developing metabolic disorders. We previously found that chronic supplementation with wheat alkylresorcinols (ARs) prevents obesity and its associated metabolic symptoms induced by a high-fat high-sucrose diet (HFHSD) in mice. The aim of this study was to examine the time-of-day-dependence of these effects in mice. METHODS: Eight-wk-old male C57 BL/6 J mice were individually housed under a 12-h light/dark cycle (Zeitgeber time; ZT0, lights on; ZT12, lights off) and given access to a HFHSD from ZT12-16 (activity onset) and ZT20-24 (activity offset) to respectively represent breakfast and dinner times for 3 wk. Thereafter, the HFHSD was replaced with the same diet containing 0.4% ARs at either ZT12-16 or ZT20-24 for 8 wk. Control mice received the HFHSD without ARs at both feeding times. RESULTS: Supplementation with ARs significantly suppressed feed efficiency when given at breakfast, but not at dinner. ARs consumed at breakfast increased fecal lipid content and decreased the expression of Fat/Cd36 in enterocytes that enhances lipid uptake, but did not affect hepatic and blood lipid levels. The consumption of ARs at breakfast also upregulated the expression of Irs1, a key gene for insulin signaling in white adipose tissue and attenuated elevated blood leptin levels induced by the diet. This led to high scores for the homeostasis model assessment of insulin sensitivity, and the adiponectin/leptin ratio, a negative index of adipose tissue dysfunction. CONCLUSIONS: These findings suggested that ARs ameliorate feed efficiency by decreasing dietary lipid absorption more effectively at the time of activity onset than offset. Further studies are needed to elucidate the molecular mechanism of the time-of-day-dependent effects of ARs on diet-induced metabolic disorders.

Wheat-ghretropins: novel ghrelin-releasing peptides derived from wheat protein.

Ghrelin is an endogenous orexigenic hormone mainly produced by stomach cells and is reported to influence appetite, gastrointestinal motility and growth hormone secretion. We observed that enzymatic digest of wheat gluten stimulated ghrelin secretion from mouse ghrelinoma 3-1, a ghrelin-releasing cell line. Further on, we characterized the ghrelin-releasing peptides present in the digest by comprehensive peptide analysis using liquid chromatography-mass spectrometry and structure-activity relationship. Among the candidate peptides, we found that SQQQQPVLPQQPSF, LSVTSPQQVSY and YPTSL stimulated ghrelin release. We then named them wheat-ghretropin A, B and C, respectively. In addition, we observed that wheat-ghretropin A increased plasma ghrelin concentration and food intake in mice after oral administration. Thus, we demonstrated that wheat-ghretropin stimulates ghrelin release both in vitro and in vivo. To the best of our knowledge, this is the first report of a wheat-derived exogenous bioactive peptide that stimulates ghrelin secretion.

Effects of onion extract containing concentrated cysteine sulfoxides on sleep quality: a randomized, double-blind, placebo-controlled, crossover study.

The objective of this randomized, double-blind, placebo-controlled, crossover study was to examine the effects of onion extract containing concentrated cysteine sulfoxides on improving sleep quality. In total, 30 healthy men and women who were dissatisfied with their sleep consumed the test food sample (onion extract tablets) for 5 days. The delta power during non-rapid eye movement sleep and the delta power per minute in the first sleep cycle increased significantly with the intake of onion extract containing concentrated cysteine sulfoxides compared with the intake of placebo. A significant decline in sleep latency was also observed. Salivary α-amylase level, a stress indicator, decreased significantly with the intake of onion extract containing concentrated cysteine sulfoxides compared with the intake of placebo. These findings indicate that onion extract containing concentrated cysteine sulfoxides alleviates stress, improves the quality of sleep and promotes smooth transition into sleep.

Effects of Whole Grain Wheat Bread on Visceral Fat Obesity in Japanese Subjects: A Randomized Double-Blind Study.

Metabolic syndrome is a risk factor for cardiovascular diseases and has become increasingly common in Japan. Epidemiological studies show inverse associations between intake of whole wheat grains and metabolic syndrome, but few dietary intervention trials have investigated the effect of whole wheat grain consumption. It was investigated whether a diet in which refined wheat bread (RW diet) was substituted by whole grain wheat bread (WW diet) would reduce visceral fat obesity in Japanese subjects. A randomized double-blind placebo-controlled intervention study was conducted in 50 Japanese subjects with body mass index (BMI) ≥ 23 kg/m2. Subjects were randomly assigned WW (WW group) or RW diets (RW group) for 12 weeks. Blood samples and computed tomography scans were obtained every 6th week. The WW group showed decrease (-4 cm2) in visceral fat area (VFA) (p < 0.05), whereas the RW group showed no significant changes. These time-dependent changes were significantly different between the groups. WW diet led to significant and safe reductions in VFA in subjects with BMI ≥ 23 kg/m2. WW diet may contribute to preventing visceral fat obesity.

Wheat alkylresorcinols reduce micellar solubility of cholesterol in vitro and increase cholesterol excretion in mice.

Epidemiological studies have shown that the consumption of whole grains can reduce risk for metabolic disorders. We recently showed that chronic supplementation with wheat alkylresorcinols (ARs) prevents glucose intolerance and insulin resistance with hepatic lipid accumulation induced in mice by a high-fat high-sucrose diet (HFHSD). This study examines the effects of ARs on the micellar solubility of cholesterol in vitro, as well as the effects of transient AR supplementation on faecal lipid excretion and plasma lipid levels in mice. We found that ARs formed bile micelles with taurocholate independently of phospholipids, and dose-dependently decreased the micellar solubility of cholesterol in a biliary micelle model. Transient AR supplementation with HFHSD increased faecal cholesterol and triglyceride contents and decreased plasma cholesterol concentrations. These suggest that one underlying mechanism through which ARs suppress diet-induced obesity is by interfering with the micellar cholesterol solubilisation in the digestive tract, which subsequently decreases cholesterol absorption.

Protective effect of red-stemmed type of Ipomoea aquatica Forsk against CCl4-induced oxidative damage in mice.

Water spinach (Ipomoea aquatica Forsk; I. aquatica) of the green-stemmed type (green type) is widely consumed, but there also exists a red-stemmed variety (red type). In the present study, the antioxidant capacity of the red type was compared to that of the green type in carbon tetrachloride (CCl(4))-treated mice. CCl(4)-induced thiobarbituric acid reactive substrate (TBARS) formation in the liver was significantly suppressed in mice fed 5% red-type I. aquatica, while the green type showed no effect. Hydrophobic oxygen radical absorbance capacity (H-ORAC(FL)) in the red type showed a lower level than that in the green type; however, lipophilic ORAC (L-ORAC(FL)) and total-ORAC(FL) levels were significantly higher in the red type than in the green type. α-Tocopherol, anthocyanidin/proanthocyanidin, and ß-carotene contents were all significantly higher in the red type than in the green type. These results suggest that the wild red-type I. aquatica contains certain lipophilic components that exert antioxidant capacities not only in vitro but also in vivo. Such effective components in the red type would be beneficial phytochemicals for suppressing several diseases related to oxidative stress.