Development of a risk management tool for prioritizing chemical hazard-food pairs and demonstration for selected mycotoxins.

We developed a simple tool for ranking chemical hazard-food pairs to assist policy makers and risk managers selecting the hazard-food pairs that deserve more attention and need to be monitored during food safety inspections. The tool is based on the derivation of a "Priority Index" (PI) that results from the ratio of the potency of the hazard and the consumer exposure. The potency corresponds to a toxicity reference value of the hazard, whereas the exposure results from the combination of the concentration of the hazard in the food, and the food consumption. Tool's assumptions and limitations are demonstrated and discussed by ranking a dataset of 13 mycotoxins in 26 food items routinely analyzed in Switzerland. The presented ranking of mycotoxin-food pairs has to be considered as relative due to scarce exposure data availability, and uncertainties in toxicity reference values. However, this representative example allows demonstrating the simplicity and the ability of the PI tool to prioritize chemical hazard-food pairs.

Glass transition associated with the jamming of vibrated granular matter.

We investigate a vibrated granular system composed of millimeter-size glass beads. When the system is submitted to a perturbation with decreasing intensity, below the fluidization limit, it evolves in a way similar to glass-forming liquids until it reaches an amorphous jammed state. This jamming transition is observed by the means of an immersed oscillator, either in the free or forced mode, while the granular medium is submitted to an external perturbation at a fixed frequency or within a frequency band. The complex susceptibility of the oscillator is measured as a function of the probe forcing frequency or as a function of the perturbation intensity. Data show that the jamming dynamics is "activated," similarly to thermal systems. The empirical control parameter is found proportional to the square root of the vibration intensity and inversely proportional to the vibration frequency. In the case of broadband external vibration, the average frequency of the power spectrum has to be considered.

Similar cholesterol-lowering properties of rice bran oil, with varied gamma-oryzanol, in mildly hypercholesterolemic men.

BACKGROUND: The cholesterol lowering properties of rice bran oil (RBO) containing differing amounts of non-saponifiable components have not been studied in humans, to our knowledge. AIM OF THE STUDY: To evaluate cholesterol lowering effects of RBO, with low and high amounts of gamma-oryzanol (ferulated plant sterols) in mildly hypercholesterolemic men. METHODS: Mildly hypercholesterolemic men, 38-64 y, starting cholesterol 4.9-8.4 mmol/l (n = 30), consumed 50 g/d peanut oil (PNO) in vehicles for 2 wks during a run-in period, then, without wash-out, were randomly equilibrated (based on initial level of cholesterol) into two groups to consume 50 g/d RBO low (0.05 g/d) or high (0.8 g/d) gamma-oryzanol for 4 wks, in a randomized, controlled, parallel design study. Subjects were free-living and consumed habitual diets with some restrictions. Plasma concentrations of total, LDL-,HDL-cholesterol and triacylglycerol were measured at base line and after 2, 4, and 6 wks. RESULTS: The two RBO types were not significantly different with respect to effects on various cholesterol parameters, at 2 and 4 wks, including total cholesterol, LDL-, HDL- and LDL/HDL cholesterol ratio. Low and high gamma-oryzanolcontaining RBO feeding for 4 wks lowered total plasma cholesterol (6.3 %), LDL-C (10.5 %) and the LDL-C/HDL-C ratio (18.9 %). CONCLUSIONS: RBO supplementation at ca. 50% total fat intake improved lipoprotein pattern in mildly hypercholesterolemic men. Methylated sterols in gamma-oryzanol are thought to be largely ineffective at inhibiting dietary cholesterol absorption, but could enhance cholesterol-lowering ability of 4-desmethylsterols. Assuming all ferulated sterols become de-ferulated in the gut, low and high gamma-oryzanolcontaining RBOs provided intestinal loads of 453 and 740 mg/d free 4-desmethylsterols, respectively. This intestinal load of 453-740 mg/d of efficacious free plant sterol equivalents had identical effects on lipoproteins.

Metabolic effects of caffeine in humans: lipid oxidation or futile cycling?

BACKGROUND: Caffeine ingestion stimulates both lipolysis and energy expenditure. OBJECTIVES: Our objectives were to determine whether the lipolytic effect of caffeine is associated with increased lipid oxidation or futile cycling between triacylglycerol and free fatty acids (FFAs) and whether the effects of caffeine are mediated via the sympathetic nervous system. DESIGN: Respiratory exchange and [1-(13)C]palmitate were used to trace lipid oxidation and FFA turnover in 8 healthy, young men for 90 min before and 240 min after ingestion of placebo, caffeine (10 mg/kg), or caffeine during beta-adrenoceptor blockade. RESULTS: During fasting conditions, there were few differences in measured variables between the 3 tests. During steady state conditions (last hour of the test) after ingestion of caffeine, lipid turnover increased 2-fold (P < 0.005), and the mean (+/-SEM) thermic effect was 13.3 +/- 2.2% (P < 0.001), both of which were greater than after ingestion of placebo or caffeine during beta-adrenoceptor blockade. After ingestion of caffeine, oxidative FFA disposal increased 44% (236 +/- 21 to 340 +/- 16 micro mol/min), whereas nonoxidative FFA disposal increased 2.3-fold (455 +/- 66 to 1054 +/- 242 micro mol/min; P < 0.01). In postabsorptive conditions, 34% of lipids were oxidized and 66% were recycled. Caffeine ingestion increased energy expenditure 13% and doubled the turnover of lipids, of which 24% were oxidized and 76% were recycled. beta-Adrenoceptor blockade decreased, but did not inhibit, these variables. CONCLUSIONS: Many, but not all, of the effects of caffeine are mediated via the sympathetic nervous system. The effect of caffeine on lipid mobilization in resting conditions can be interpreted in 2 ways: lipid mobilization alone is insufficient to drive lipid oxidation, or large increments in lipid turnover result in small increments in lipid oxidation.

Short-term dietary conjugated linoleic acid supplementation does not enhance the recovery of immunodepleted dexamethasone-treated rats.

BACKGROUND: Conjugated linoleic acid (CLA) has been reported to decrease fat deposition, and increase lean body mass. This has been broadly inferred to mean that CLA alters protein turnover. However, data to test the effects of CLA on protein turnover are lacking. An enhancement in immune responses by CLA has also been demonstrated. AIM OF THE STUDY: The objective of this study was to determine the potential for dietary CLA and protein intervention to improve nutritional and functional recovery in an animal model of catabolic stress and immunodepletion. METHODS: Diets varying in their protein levels in the presence or absence of CLA were tested for their effects on the recovery of glucocorticoid (intraperitoneal injection of dexamethasone, 120 mg/kg) treated rats. Following steroid injection, rats were fed 4 dietary treatments for 4 d. The diets contained 10 or 20 g/100 g protein with or without 0.5 g/100 g CLA. RESULTS: Dexamethasone treatment resulted in a decreased food intake and loss of weight, independent of dietary treatment. A higher number of blood monocytes occurred in rats fed the high CLA diets. The protein fractional synthesis rate in spleens of rats fed the diets containing either high proteins or CLA were higher compared to those fed diets with low protein content or without CLA, respectively. CLA, consumed post-dexamethasone treatment, did not improve protein turnover in the other tissues studied, including gut mucosa, liver, muscle and thymus. CONCLUSIONS: The present study was performed to determine the effect of CLA in acute conditions, as opposed to a preventive approach, on the recovery from a catabolic stress with immunodepletion. Overall, no effect of short-term feeding CLA on the recovery from dexamethasone-mediated immunodepletion was observed.

Cholesterol-lowering properties of amaranth grain and oil in hamsters.

Amaranth was an important ancient grain and has current nutritional potential, being high in protein, fiber, lysine, magnesium, calcium, and squalene. Limited, inconsistent evidence demonstrates amaranth grain or oil can lower cholesterol in animal models. In the present study, hamsters received hypercholesterolemic diets consisting of a control, 10 or 20% Amaranthus cruentus grain, or 2.5 or 5% crude amaranth oil for four weeks. Amaranth oil (5%) decreased total and non-high-density lipoprotein (HDL) cholesterol by 15 and 22%, respectively, compared to control. Amaranth grain (20%; providing 1.4% amaranth oil) lowered non-HDL cholesterol and raised HDL cholesterol. Amaranth grain and oil decreased very low-density lipoprotein (VLDL) cholesterol by 21-50%; and increased fecal excretion of particular neutral sterols and the bile acid ursodeoxycholate. Amaranth oil (5%) additionally increased the cholesterol synthesis rate, possibly due to compensatory mechanisms; and decreased hepatic cholesterol ester, indicating reduced cholesterol ester availability for VLDL secretion and consistency with reduced VLDL cholesterol. Amaranth thus affected absorption of cholesterol and bile acids, cholesterol lipoprotein distribution, hepatic cholesterol content, and cholesterol biosynthesis. Amaranth grain and oil did not affect these pathways identically.