Tsuneyuki Noda

The 10trans, 12cis isomer of conjugated linoleic acid promotes energy metabolism in OLETF rats

OBJECTIVE We investigated the effect of conjugated linoleic acid (CLA) on energy metabolism in Otsuka Long-Evans Tokushima Fatty (OLETF) rats. METHODS In experiment 1, male OLETF rats were fed either control diet, 10% safflower oil or CLA diet, 9% safflower oil plus 1% CLA for 4 wk. In experiment 2, male OLETF rats were fed either 9c,11t-CLA diet, 9% safflower oil plus 1% 9c,11t-CLA-rich oil or 10t,12c-CLA diet, 9% safflower oil plus 1% 10t,12c-CLA-rich oil for 10 d. RESULTS In experiment 1, after 4 wk of feeding, serum and hepatic triacylglycerol concentrations in the CLA group were decreased significantly as compared with the control group. The CLA diet increased oxygen consumption and energy expenditure as compared with the control diet in OLETF rats. In experiment 2, a significant reduction of serum and hepatic triacylglycerol concentrations was seen in the 10t,12c-CLA group as opposed to the 9c,11t-CLA group. Oxygen consumption and energy expenditure were significantly higher in the 10t,12c-CLA group than in the 9c,11t-CLA group. CONCLUSIONS These results demonstrated that the hypolipidemic effect and the enhancement of energy metabolism by CLA can be attributed to the effect of the 10t,12c-CLA isomer.

Effects of a Chitosan Intake on the Fecal Excretion of Dioxins and Fat in Rats

We evaluated the effects of the intake of various dietary fibers on the fecal excretion of dioxins in rats. The rats were fed five types of dietary fiber diets, including a chitosan diet and control diet, for 20 d and then dioxins (120 ng/rat) were orally administered on day 15. The excretion of fecal dioxins was significantly higher in the chitosan group than in the control group, and dioxin excretion was positively correlated with fecal fat excretion. A comparison of the different types of chitosan showed that the efficacy of chitosan for fecal fat excretion was partly related to its viscosity. The chitosan intake promoted fecal dioxin excretion when the rats were exposed to highly toxic dioxins, and this excretion of fecal dioxins was related to the fecal fat excretion, suggesting that chitosan might be useful for reducing the adverse effects caused by lipophilic xenobiotics.

Effects of a soybean nutrition bar on the postprandial blood glucose and lipid levels in patients with diabetes mellitus

We investigated the influence of a soybean nutrition bar made from whole soy powder on the blood glucose, insulin and lipid levels in comparison with a test cookie with the same amount of energy in patients with diabetes mellitus. In the cross-over designed study, meal tolerance tests using the soybean nutrition bar and test cookie were performed. Two kinds of test meals were used: Study 1 80 kcal, Study 2 592 kcal. The blood glucose response was significantly lower in the soybean nutrition bar trial than in the cookie trial (Studies 1 and 2, p < 0.001). The blood insulin response was also significantly lower in the soybean nutrition bar trial than in the cookie trial (Study 2, p < 0.001). The blood triglyceride and non-esterified fatty acid responses were not significantly different between the two trials, nor were the changes in breath H2 enrichment (Study 2). The soybean nutrition bar did not induce postprandial hyperglycaemia in diabetic patients unlike the isoenergetic test cookies.

Effects of Chitosan Intake on Fecal Excretion of Bisphenol A and Di(2-ethyl)phthalate in Rats

We evaluated the effects of chitosan intake on fecal excretion of bisphenol A (BPA) and di(2-ethyl)phthalate (DEHP) in rats. The rats were fed a chitosan diet (CHI group) or a control diet (control group) for 10 d and orally administrated BPA or DEHP (100, 500 mg/kg body weight, respectively) on day 4. Feces were collected and the rates of fecal excretion of BPA and DEHP were calculated. Fecal excretion rates of BPA and DEHP were significantly higher in the CHI group than in the control group. A significant negative correlation was observed between the fecal excretion rates of BPA and DEHP and apparent fat digestibility. Furthermore, the CHI group showed not only increased but also accelerated BPA excretion into the feces. In conclusion, we found that that chitosan intake significantly increased the fecal excretion of BPA, DEHP, and fat, suggesting that it might be useful for reducing adverse effects caused by lipophilic xenobiotics.

Effect of Chitosan Intake on Fecal Excretion of Dioxins and Polychlorinated Biphenyls in Healthy Men

Six healthy male subjects were treated with 0 g, 1 g, 3 g, and 0 g of chitosan for the first, second, third, and fourth of four weeks, respectively. They were administered chitosan before breakfast on the second, third, and fourth days of the week, and fecal specimens were collected corresponding to the prescribed diet consumed for breakfast on the second day to breakfast on the fourth day. Fecal excretion of dioxins and polychlorinated biphenyls (PCBs) was promoted by intake of 3 g of chitosan (p=0.0589 and p<0.05 respectively), and was positively correlated with that of fat (p<0.01 for both). We found that chitosan intake increased the fecal excretion of dioxins and PCBs, as well as that of fat, suggesting that it might be useful for reducing the adverse effects of lipophilic endocrine-disrupting chemicals.

Effect of prehydration on nasal mucociliary clearance in low relative humidity

OBJECTIVE Nasal mucociliary clearance, which plays an important role in defending the respiratory system, tends to decrease under conditions of low relative humidity (RH). The purpose of this randomized cross-over study was to investigate the preventive effect of prehydration on nasal mucociliary clearance under low RH conditions. METHODS Fourteen young healthy subjects were assigned to three interventions: prehydration (6ml/kg body weight) using water (W), prehydration using a carbohydrate-electrolyte beverage (CE), and control conditions (Cont) with no prehydration. For each intervention trial, subjects sat for 4h in an environmental chamber (23°C, 10% RH). Nasal mucociliary clearance was measured by the saccharin transit time (ST). Furthermore, a dry sensation of the mucosa, urine volume, and body weight were measured at the baseline, 2h and 4h after entering the environmental chamber, respectively. RESULTS ST was prolonged under the Cont conditions after entering the environmental chamber. Prehydration with CE led to a significantly lower ST compared to the Cont pretreatment at 2h, whereas the W trial showed no significance difference in comparison to the Cont values. CONCLUSION These results suggest that prehydration with a carbohydrate-electrolyte beverage is therefore beneficial for maintaining better nasal mucociliary clearance at least for 2h under low RH conditions.