European Journal of Nutrition (v.48, #2)

Allicin up-regulates cellular glutathione level in vascular endothelial cells by Limor Horev-Azaria; Shlomit Eliav; Nira Izigov; Sarah Pri-Chen; David Mirelman; Talia Miron; Aharon Rabinkov; Meir Wilchek; Jasmine Jacob-Hirsch; Ninette Amariglio; Prof. Naphtali Savion (67-74).
Allicin in garlic is the primary active compound known to rapidly interact with free thiols.To examine the effect of allicin on gene expression and glutathione cellular level in vascular endothelial cells.Cultured endothelial cells were exposed to allicin; mRNA was prepared and subjected to Micro-array and Real-Time PCR. Glutathione cellular level was determined on cell lysates.Micro-array analysis demonstrated allicin-induced up- and down-regulation of 116 and 100 genes, respectively. Up-regulated genes included the phase II detoxifying enzymes thioredoxin reductase 1 and 2, heme oxygenase-1 and glutamate cysteine lygaze modifier subunit, the rate limiting enzyme in glutathione biosynthesis. Endothelial cells exposed to allicin and its derivatives containing glutathione or cysteine residues increased cellular glutathione. Allicin increased the glutathione level in a concentration and time-dependent manner up to 8-fold at a concentration of 10–20 µM after 28 h exposure. Furthermore, allicin derivative-treated cultures demonstrated a 50% decrease in tBuOOH cytotoxicity.These results may suggest a putative role for allicin and its derivatives in preventing reactive oxygen species damage by up-regulating the phase II detoxifying enzymes and increasing the cellular glutathione level.
Keywords: endothelial cells; glutathione; oxidative stress; antioxidant capacity; thiols

The two main sources of vitamin D3 are de novo synthesis induced by exposure to ultraviolet (UV) light from the sun, and diet. Vitamin D3 deficiency causes rickets or osteoporosis. Oak mushrooms (Lentinula edodes) that are exposed to UV radiation contain enhanced vitamin D2 and have much higher calcium content than unmodified (non-irradiated) mushrooms. Such modified edible mushrooms have been proposed as a natural alternative source of dietary vitamin D. In the current study, we have examined whether modified oak mushrooms could improve or prevent osteoporosis-like symptoms in mice fed with low calcium and vitamin D3-deficient diet. Four-week-old male mice were fed low calcium, vitamin D3-deficient diets supplemented with 5, 10, or 20% unmodified, calcium-enhanced, or calcium plus vitamin D2-enhanced oak mushrooms for 4 weeks. To assess the effects of the supplemented diets, we evaluated femur density and length, bone histology, the expression of active calcium transport genes, and serum calcium levels. Mice fed with low calcium and vitamin D3-deficient diet developed osteoporosis-like symptoms within 4 weeks. Femur density and tibia thickness were significantly higher in mice fed calcium plus vitamin D2-enhanced mushrooms, and the expression of duodenal and renal calcium transport genes was significantly induced. These results indicate that in mice, vitamin D2 and/or calcium derived from irradiated oak mushrooms may improve bone mineralization through a direct effect on the bone, and by inducing the expression of calcium-absorbing genes in the duodenum and kidney.
Keywords: L. edodes ; active calcium transporting genes; osteoporosis; vitamin D2

Effects of soy isoflavone consumption on bone structure and milk mineral concentration in a rat model of lactation-associated bone loss by Catherine A. Peterson PhD, RD; Jennifer D. Schnell MS; Karen L. Kubas MS; George E. Rottinghaus PhD (84-91).
Like menopause, during complete lactation, circulating estrogen concentrations are markedly reduced, resulting in amplified bone resorption.To investigate the effects of soy isoflavones, common dietary components used to mitigate the bone loss of menopause, on the bone loss associated with lactation.Lactating rats were randomized to one of four diets supplemented with different levels of soy isoflavones (0, 2, 4, 8 mg aglycone isoflavone/g protein). Milk was collected from all dams between days 12 and 15 of lactation and was analyzed for calcium, phosphorus and genistein concentrations. Serum and bones from half of the animals from each diet group were taken at weaning and from the remaining half at 4 weeks post-weaning. Bones underwent histomorphometric analysis and serum was used for genistein determinations.Serum genistein and milk concentrations reflected dietary isoflavone dose. Isoflavone intake had no effect on any of the bone changes associated with lactation or recovery. Milk calcium and mineral concentrations were unaffected by dietary isoflavones.Consumption of soy isoflavones, in levels that can be readily attained through soy foods, have neither protective effects on bone nor deleterious effects on milk quality or quantity during lactation.
Keywords: bone loss; isoflavones; lactation; rat model; genistein

Effects of high and normal soyprotein breakfasts on satiety and subsequent energy intake, including amino acid and ‘satiety’ hormone responses by Margriet A. B. Veldhorst; Arie G. Nieuwenhuizen; Ananda Hochstenbach-Waelen; Klaas R. Westerterp; Marielle P. K. J. Engelen; Robert-Jan M. Brummer; Nicolaas E. P. Deutz; Margriet S. Westerterp-Plantenga (92-100).
The role of dietary protein in short term satiety is of interest with respect to body weight regulation.To compare the effects of a high versus a normal soyprotein breakfast on satiety and subsequent energy intake (EI), including ‘satiety’ hormones and plasma amino acid responses.Twenty-five healthy subjects (mean ± SEM, BMI: 23.9 ± 0.3 kg/m2; age: 22 ± 1 years) received a subject-specific standardized breakfast: a custard with soy as single protein type with either 10/55/35 (normal-protein) or 25/55/20 (high-protein) En% protein/carbohydrate/fat in a randomized, single-blind design. Appetite profile (Visual Analogue Scale, VAS), plasma glucose, insulin, Glucagon-like Peptide 1, ghrelin, and amino acid concentrations were determined for 4 h, determining the sensitive time point to assess EI. Since at 180 min glucose and insulin concentrations still were significantly different, in a second set of experiments subjects received an ad lib lunch at 180 min after the breakfasts; EI was assessed.Overall the 25 En% soy-custard was rated as being more satiating than the 10 En% soy-custard (P < 0.01) and there was a difference at 20 min after breakfast (64 ± 5 vs. 52 ± 5 mmVAS, P < 0.05), related to higher postprandial taurine concentrations (P < 0.05). Insulin response was increased more after the 25 En% than after the 10 En% soy-custard (AUC: 7,520 ± 929 vs. 4,936 ± 468 mU/l h, P < 0.001). There was no difference in EI (25 En%: 3,212 ± 280 kJ vs. 10 En%: 3,098 ± 286 kJ, ns).A high soyprotein breakfast is more satiating than a normal soyprotein breakfast related to elevated taurine and insulin concentrations.
Keywords: satiety; energy intake; soyprotein; taurine; insulin

Carnosic acid reduces cytokine-induced adhesion molecules expression and monocyte adhesion to endothelial cells by Ya-Mei Yu PhD, MPH; Chin-Huei Lin MS; Hsu-Chin Chan PhD; Hong-Der Tsai MD (101-106).
Expression of cell adhesion molecules on the endothelium and the attachment of monocytes to endothelium may play a major role in the early atherogenic process.We investigated the effects of carnosic acid on the adhesion of U937 cells to IL-1β-treated human umbilical vein endothelial cells (HUVECs), as well as on the expression of adhesion molecules.Our data showed that pretreatment with 10 and 20 µmol/l carnosic acid significantly reduced the number of U937 cells adhering to IL-1β-treated HUVECs. In addition, we found that 20 µmol/l carnosic was more effective than 10 µmol/l carnosic acid at inhibiting expression of cell adhesion molecules (ICAM-1, VCAM-1, and E-selectin), the nuclear translocation of NF-κB subunits p65 and p50, and the production of ROS in IL-1β-stimulated HUVECs.We conclude that carnosic acid inhibits IL-1β-induced ICAM-1, VCAM-1 and E-selectin expression in HUVECs through a mechanism that involves NFκB. We propose that the reduction in binding of human monocytic cell line U937 to IL-1β-treated HUVECs is due to the anti-inflammatory properties of carnosic acid.
Keywords: carnosic acid; adhesion molecules; NFκB; IL-1β; reactive oxygen species

Effects of seafood consumption and weight loss on fasting leptin and ghrelin concentrations in overweight and obese European young adults by Alfons Ramel; Dolores Parra; J. Alfredo Martinéz; Mairead Kiely; Inga Thorsdottir (107-114).
Energy restriction affects circulating leptin and ghrelin concentrations.To investigate whether seafood consumption affects fasting leptin and ghrelin concentrations in addition to weight loss.In this 8-week dietary intervention, subjects (324 Icelandic, Spanish and Irish subjects, 20–40 years, BMI 27.5–32.5 kg/m2) were randomized to energy-restricted diets (−30%) of identical macronutrient composition but different amount of seafood: control (no seafood); lean fish (150 g cod, three times per week); fatty fish (150 g salmon, three times per week); EPA&DHA [daily docosahexaenoic (DHA)/eicosapentaenoic acid (EPA) capsules]. Anthropometric data, ghrelin, leptin, and insulin were measured at baseline and endpoint. Linear models investigated the effects of seafood on fasting leptin, ghrelin and insulin.Body weight (−5.2 ± 3.0 kg), leptin (−34.8%) and insulin (−13.5%) decreased, while ghrelin increased (5.6%) (all P < 0.001). According to linear models endpoint insulin was significantly lower in the EPA&DHA group (−16.4%, P = 0.025) compared to control, endpoint leptin in men was lower in the salmon group (−22.9%, P = 0.026), and the EPA&DHA group tended to have higher endpoint ghrelin (5.6%, P = 0.060), an effect seen only in women indicated by a significant gender × EPA&DHA interaction. Weight loss explained the effects of fatty seafood on leptin and ghrelin, but not insulin.Consumption of fatty seafood can modulate fasting insulin, ghrelin and leptin during an 8-week intervention. Effects are partly gender specific and are partly explained by weight loss. Consumption of lean fish does not affect circulating hormones in comparison to control. The most consistent effect on circulating hormones is mediated by weight loss.
Keywords: leptin; ghrelin; insulin; weight loss; LC n-3 fatty acids

Relative bioavailability of micronized, dispersible ferric pyrophosphate added to an apple juice drink by Mark A. Roe; Rachel Collings; Jurian Hoogewerff; Susan J. Fairweather-Tait (115-119).
Food iron fortification is a sustainable and relatively simple strategy to reduce/prevent iron deficiency but is a challenge for the food industry because of possible adverse organoleptic changes caused by the added iron. A micronized dispersible ferric pyrophosphate, trademarked as SunActive Fe®, has recently been developed. SunActive Fe® has a small particle size, is water soluble and may be suitable for fortifying liquid products.To determine the relative bioavailability of SunActive Fe® and its suitability for addition to pure apple juice.Iron absorption from SunActive Fe® added to pure apple juice (Minute Maid®) was compared with absorption from ferrous sulphate, a highly bioavailable form of iron, in 15 women with relatively low iron stores. Both forms of iron were enriched with an iron stable isotope and iron absorption from the apple juice drinks was calculated from the isotopic enrichment of red blood cells 14 days after the last test meal.Although mean absorption of iron from SunActive Fe® was significantly lower than from ferrous sulphate (5.5% compared with 9.1%), the mean bioavailability of SunActive Fe® iron relative to ferrous sulphate was 0.6, indicating that it is a good source of bioavailable iron. Iron Absorption from SunActive Fe® was positively correlated (r = 0.97, P = 0.01) with absorption from ferrous sulphate, and negatively correlated with serum ferritin concentration (ferrous sulphate r = −0.81, P < 0.001; SunActive Fe® r = −0.76, P = 0.01).SunActive Fe® was well absorbed from apple juice and is a potentially useful fortificant for liquid food products.
Keywords: iron absorption; fortification; SunActive Fe® ; ferric pyrophosphate; iron bioavailability

Allium vegetable intake and risk of acute myocardial infarction in Italy by Carlotta Galeone ScD, PhD; Alessandra Tavani ScD; Claudio Pelucchi ScD; Eva Negri ScD; Carlo La Vecchia MD (120-123).
Interest in potential benefits of allium vegetables has its origin in antiquity, but the details of these benefits are still open to discussion. Only two epidemiological studies considered the relation between dietary intake of allium vegetables and cardiovascular diseases.To provide further information we analysed the relationship between onion and garlic intake and acute myocardial infarction (AMI).We used data from a case–control study of 760 patients with a first episode of non-fatal AMI and 682 controls admitted to the same hospitals. Information was collected by trained interviewers using a validated and reproducible food-frequency questionnaire. Multivariate odds ratios (ORs) and 95% confidence intervals (CIs) were obtained after allowance for recognized confounding factors.Compared with non-users, the ORs of AMI for subsequent categories of onion intake were 0.90 (95% CI: 0.69–1.21) for <1 portion of onion per week and 0.78 (95% CI: 0.56–0.99) for ≥1 portion per week. For garlic, the ORs were 0.84 (95% CI: 0.66–1.09) for intermediate and 0.94 (95% CI: 0.68–1.32) for high use, compared with no or low use.The current study, the first from Mediterranean countries, suggests that a diet rich in onions may have a favourable effect on the risk of AMI.
Keywords: onion; garlic; allium vegetables; diet; myocardial infarction

Intraduodenal administration of peptone prepared from soybean β-conglycinin (BconP) stimulates cholecystokinin (CCK) secretion from enteroendocrine cells, and suppresses food intake in rats. However, the sensing mechanism of BconP by CCK-producing cells is unknown.We investigated signal transduction pathways mediating CCK secretion in response to BconP in the murine CCK-producing cell line, STC-1.STC-1 cells were seeded in 48-well culture plates until sub-confluent and CCK secretion was examined under various conditions. CCK concentration was determined by the enzyme immunoassay.BconP dose-dependently induced CCK secretion in STC-1 cells. Treatment with BAPTA-AM, an intracellular Ca2+ chelator, reduced BconP-induced CCK secretion, however, removal of extracellular Ca2+ did not affect the secretory response. Treatment with 2-amino borate (2-APB) reduced CCK releasing responses, suggesting the involvement of IP3. In addition, BconP failed to induce CCK secretion after treatment with the Gαq protein inhibitor (YM-254890).These results indicate that Gαq pathway is responsible for BconP-induced CCK secretion in STC-1 cells, and suggest the involvement of a Gαq-coupled GPCR(s) in dietary peptide sensing in enteroendocrine cells.
Keywords: enteroendocrine cells; cholecystokinin; dietary peptide; GPCR