European Journal of Nutrition (v.50, #5)

Striking a new path by Gerhard Rechkemmer (291-292).

In the last decade, a growing scientific and medical interest has emerged toward cardiovascular effects of dietary nitrite and nitrate; however, many questions concerning their mode of action(s) remain unanswered. In this review, we focus on multiple mechanisms that might account for potential cardiovascular beneficial effects of dietary nitrite and nitrate.Beneficial changes to cardiovascular health from dietary nitrite and nitrate might result from several mechanism(s) including their reduction into nitric oxide, improvement in endothelial function, vascular relaxation, and/or inhibition of the platelet aggregation. From recently obtained evidence, it appears that the longstanding concerns about the toxicity of oral nitrite or nitrate are overstated.Dietary nitrite and nitrate may have cardiovascular protective effects in both healthy individuals and also those with cardiovascular disease conditions. A role for nitrite and nitrate in nitric oxide biosynthesis and/or in improving nitric oxide bioavailability may eventually provide a rationale for using dietary nitrite and nitrate supplementation in the treatment and prevention of cardiovascular diseases.
Keywords: Cardiovascular disease; Diet; Endothelial dysfunction; Nitric oxide; Nitrite; Nitrate

Association of serum 25-hydroxyvitamin D with the risk of death in a general older population in Finland by Jyrki K. Virtanen; Tarja Nurmi; Sari Voutilainen; Jaakko Mursu; Tomi-Pekka Tuomainen (305-312).
To investigate the association between serum 25-hydroxyvitamin D [25(OH)D] concentration, a marker of vitamin D status, and risk of all-cause and cardiovascular mortality in a general older population with relatively low average serum 25(OH)D concentrations.The study population included 552 men and 584 women aged 53–73 years who were free of CVD and cancer at baseline in 1998–2001 from the prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study. Deaths were ascertained by a computer linkage to the national cause of death register. All deaths that occurred from the study entry to December 31, 2008, were included. Cox proportional hazards regression models were used to analyze the association between serum 25(OH)D and risk of death.The mean serum 25(OH)D concentration was 43.7 nmol/L (SD 17.8), with a strong seasonal variation. During the average follow-up of 9.1 years, 87 participants died, 35 from cardiovascular disease (CVD). After multivariable-adjustments, the hazard ratios (HR) for all cause death in the tertiles of serum 25(OH)D were 1, 1.68 (95% CI: 0.92, 3.07) and 2.06 (95% CI: 1.12, 3.80), p for trend = 0.02.Our study supports the accumulating evidence from epidemiological studies that vitamin D deficiency is associated with increased risk of death. Large-scale primary prevention trials with vitamin D supplementation are warranted.
Keywords: 25-hydroxyvitamin D; Mortality; Prospective study; Vitamin D

Comparative effects of dietary flavanols on antioxidant defences and their response to oxidant-induced stress on Caco2 cells by Ildefonso Rodríguez-Ramiro; María Ángeles Martín; Sonia Ramos; Laura Bravo; Luis Goya (313-322).
Flavanols are an important fraction of our diet both for their antioxidant capacity and because they are constituents of greatly accepted foodstuffs such as tea, wine and cocoa. In addition to their antioxidant activity by directly scavenging intracellular reactive oxygen species (ROS), flavanols have been recently shown to enhance protective enzymes. The objective was to evaluate the antioxidant response of colon-derived Caco2 cells to dietary flavanols.Four representative flavanols were selected: epicatechin (EC), epicatechin-3-gallate (ECG), epigallocatechin-3-gallate (EGCG) and procyanidin B2 (PB2). Cell viability, concentration of ROS and reduced glutathione (GSH), and activity of antioxidant/detoxification enzymes and caspase 3 were determined.Treatment of Caco2 cells with flavanols decreased ROS production but did not affect GSH content. ECG induced glutathione peroxidase (GPx), whereas PB2 evoked a dose-dependent increase in GPx, glutathione reductase and glutathione-S-transferase. Enhancement of the antioxidant defences implies an improved cell response to an oxidative challenge. Hence, Caco2 cells treated 20 h with the flavanols, especially PB2, and then submitted to an oxidative stress induced by a pro-oxidant, tert-butyl-hydroperoxide, showed a reduced ROS production, restricted activation of caspase 3 and higher viability than cells plainly submitted to the stressor.Flavanols protect Caco2 cells against an induced oxidative stress and subsequent cellular death by reducing ROS production and preventing caspase-3 activation. In particular, PB2 increases the activity of antioxidant/detoxification enzymes and thus protects Caco2 cells by directly counteracting free radicals and also by activating the antioxidant defence system.
Keywords: Epicatechin; Epicatechin gallate; Epigallocatechin-3-gallate; Procyanidin B2; Oxidative stress; Flavonoids

Adipocyte fatty acid binding protein (A-FABP) present in macrophages has been implicated in the integration of lipid metabolism and inflammatory response, contributing to development of insulin resistance and atherosclerosis.This study was conducted to test the hypothesis that the role of fatty acids in the inflammatory pathways is mediated through the modulation of A-FABP expression in macrophages.Murine RAW 264.7 macrophages were treated with inflammatory insults and fatty acids for quantitative real-time PCR and Western blot analysis. The cells were treated with trichostatin A (TSA), a histone deacetylase inhibitor, for elucidating mechanisms for the regulation of A-FABP expression by fatty acids. RNA interference (RNAi) to knock down A-FABP was utilized to assess its role in inflammatory gene expression.When RAW 264.7 were incubated with lipopolysaccharides (LPS; 100 ng/ml) or 2.5 ng/ml of tumor necrosis factor α for 18 h, A-FABP mRNA and protein levels were drastically increased. Unsaturated fatty acids (100 μmol/l in complexed with BSA) such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, and eicosapentaenoic acid, significantly repressed the basal as well as LPS-induced A-FABP expression, whereas palmitic acid did not elicit the same effect. TSA increased A-FABP mRNA levels and abolished the repressive effect of linoleic acid on A-FABP expression in unstimulated and LPS-stimulated macrophages. Depletion of A-FABP expression by 70–80% using RNAi markedly decreased cyclooxygenase 2 mRNA abundance and potentiated the repression by linoleic acid.Unsaturated fatty acids inhibited the basal as well as LPS-induced A-FABP expression. The mechanism may involve histone deacetylation and anti-inflammatory effect of unsaturated fatty acids may be at least in part attributed to their repression of A-FABP expression in RAW 264.7 macrophages.
Keywords: Adipocyte fatty acid binding protein; Fatty acids; RAW 264.7 macrophages; Histone deacetylase; Cyclooxygenase 2

Whey protein precludes lipid and protein oxidation and improves body weight gain in resistance-exercised rats by Fabiano Kenji Haraguchi; Marcelo Eustáquio Silva; Leandro Xavier Neves; Rinaldo Cardoso dos Santos; Maria Lúcia Pedrosa (331-339).
Resistance exercise such as weight-lifting (WL) increases oxidation products in plasma, but less is known regarding the effect of WL on oxidative damage to tissues. Dietary compounds are known to improve antioxidant defences. Whey protein (WP) is a source of protein in a variety of sport supplements and can enhance physical performance.To evaluate the effect of WL on biomarkers of lipid and protein oxidation, on liver antioxidants and on muscle growth in the absence or presence of WP in rats.Thirty-two male Fisher rats were randomly assigned to sedentary or exercise-trained groups and were fed with control or WP diets. The WL programme consisted of inducing the animals to perform sets of jumps with weights attached to the chest. After 8 weeks, arteriovenous blood samples, abdominal fat, liver and gastrocnemius muscle were collected for analysis.WP precludes WL-mediated increases in muscle protein carbonyl content and maintains low levels of TBARS in exercised and sedentary animals. WL reduced liver CAT activity, whereas WP increased hepatic glutathione content. In addition, WL plus WP generated higher body and muscle weight than exercise without WP.These data suggest that WP improves antioxidant defences, which contribute to the reduction of lipid and protein oxidation as well as body and muscle weight gain in resistance-exercised rats.
Keywords: Whey protein; Weight-lifting; Lipid oxidation; Protein oxidation; Antioxidants

To assess the effectiveness of a dietary intervention combined with fortified dairy products on bone metabolism and bone mass indices in postmenopausal women.Forty postmenopausal women (55–65 years old) were equally randomized into a dietary group (DG), receiving daily and for 30 months, 1,200 mg of calcium and 7.5 μg of vitamin D3 for the first 12 months that increased to 22.5 μg for the remaining 18 months of intervention through fortified dairy products; and a control group (CG). Differences in the changes of bone metabolism and bone mass indices were examined with repeated measures ANOVA.A significant increase was observed for PTH levels only in the CG during the first six winter months of intervention (p = 0.049). After 30 months of intervention, during winter, serum 25(OH)D significantly decreased in the CG while remained in the same high levels as in the summer period in the DG. Serum RANKL levels decreased significantly in the DG compared with the increase in the CG during the 30-month intervention period (p = 0.005). Serum CTx decreased significantly in the DG after six (−0.08; −0.12 to −0.03) and 12 (−0.03; −0.08 to −0.02) months of intervention. Finally, the DG had more favorable changes in total body BMD than the CG (p < 0.001).Increasing dietary intake of calcium and vitamin D in osteopenic postmenopausal women appears to be effective in producing favorable changes in several bone metabolism and bone mass indices and in counterbalancing seasonal variations in hormonal and biochemical molecules.
Keywords: Calcium and vitamin D; RANKL; Bone metabolism; Postmenopausal women; Physiology

Successful weight loss and maintenance in everyday clinical practice with an individually tailored change of eating habits on the basis of food energy density by Volker Schusdziarra; Margit Hausmann; Corina Wiedemann; Julie Hess; Cornelia Barth; Stefan Wagenpfeil; Johannes Erdmann (351-361).
Weight change was analyzed in a cohort of obese patients whose eating habits were changed individually mainly on the basis of food energy density (ED) to evaluate the feasibility of this concept for a larger controlled trial.Five hundred and thirteen outpatients were treated between January 2003 and December 2006. Dietary counseling was based on a pretreatment food diary. In January 2008, a follow-up (FU) was made. For pre- and post-change eating habits, 5184 dietary protocols of 189 patients were analyzed.During 10.5 months of treatment, patients lost weight from an initial BMI of 38.8 ± 8.5 by −0.195 kg/m2 per month; 36% had weight loss >5%, 44% lost 0–4.9% and 20% had weight gain. At follow-up, 413 patients (80.5%) were reached of whom 80 were still in treatment while 333 were considered as self-treatment (ST) group. The ST group had further weight loss by −0.053 kg/m2 per month over 16.8 months (40% weight loss, 46% maintenance and 14% weight gain), and 164 patients with type-2-diabetes had greater weight loss compared to those without diabetes during ST (Δ-BMI-0.166 vs. −0.028 points/month; p < 0.0001). Energy intake (EI) was reduced by lower ED, beverages and number of meals. Average carbohydrate, fat and protein intake was reduced by 28, 42, and 7%, respectively.In a unselected cohort of substantially obese patients, the individual change of eating habits based primarily on food ED in conjunction with beverage intake and meal frequency weight loss continued beyond the supported treatment phase indicating a good patient adherence. We consider these data as an encouraging pilot study that certainly requires confirmation under controlled conditions.
Keywords: Obesity treatment; Weight maintenance; Self-treatment; Dietary counseling; Type 2 diabetes; Macronutrients; Treatment cost

Transepithelial heme-iron transport: effect of heme oxygenase overexpression by M. J. Mendiburo; S. Le Blanc; A. Espinoza; F. Pizarro; M. Arredondo (363-371).
Heme iron is found in the diet mainly in the form of hemoglobin and myoglobin. It is known that heme iron (heme-Fe) and inorganic iron are absorbed differently. Intracellularly, heme oxygenase-1 (HO1) participates in the cleavage of the heme ring producing biliverdin, CO and ferrous iron. Iron released from heme becomes part of labile iron pool, and it can be stored in ferritin or released through the basolateral membrane. The mechanism by which heme-Fe is metabolized within cells is not completely understood.This study focused on the uptake and transport of heme iron and on the role of heme oxygenase-1 on heme iron metabolism.Caco-2 cells were incubated with different concentrations of heme-Fe. A full-length heme oxygenase-1 cDNA was expressed in Caco-2 cells and intracellular iron and heme-Fe content, heme uptake, heme and iron transport and heme oxygenase-1 immunolocalization were assessed in these cells.Heme-Fe was bioavailable and induced an intracellular increase in iron, ferritin and HO1 levels and a decrease in DMT1 expression. In cells overexpressing HO1, heme-Fe uptake and transepithelial Fe transport was higher than in controls. Most heme-Fe was metabolized to free iron, most of which was found mainly in the basolateral chamber. However, there is a fraction of heme that is delivered intact to the basolateral side. In a high heme-Fe condition, HO1 is found near the plasma membrane.These results suggest that heme oxygenase-1 catabolizes most of the heme-Fe and favors iron influx and efflux in intestinal cells.
Keywords: Heme-Fe; Transepithelial transport; Caco-2 cells; Heme oxygenase

Vitamin D deficiency is an independent predictor of elevated triglycerides in Spanish school children by Elena Rodríguez-Rodríguez; Rosa M. Ortega; Liliana G. González-Rodríguez; Ana M. López-Sobaler (373-378).
To determine the association between vitamin D status and the serum lipid profile in children.The subjects of this cross-sectional study were 149 Spanish school children (8–13 years of age). The anthropometric data collected were weight and height, from which the body mass index (BMI) was calculated. Serum 25(OH)D concentrations were measured by chemiluminescent assay. Triglycerides were determined by enzyme colorimetry; total cholesterol and HDL-cholesterol were determined by the cholesterol esterase method. The LDL-cholesterol concentrations were determined mathematically.Compared to children with serum 25(OH)D concentrations in the fourth quartile, those in the first had higher triglyceride (86.0 ± 35.7 vs. 64.1 ± 26.7 mg/dL; p < 0.05). After adjusting for age, sex, BMI, and physical activity, the serum 25(OH)D level was found to be inversely proportional to the triglyceride (r = −0.857; p = 0.010). While age, sex, BMI, and physical activity explained 12% of the variance of the HDL-cholesterol figures, the inclusion of serum 25(OH)D allowed 23% of the variance to be explained.A low serum vitamin D levels in children is associated with high triglyceride levels.
Keywords: 25(OH)D; Serum lipids; Children

Differentiation- and polarization-dependent zinc tolerance in Caco-2 cells by Nina Zemann; Adolf Zemann; Petra Klein; Ibrahim Elmadfa; Manfred Huettinger (379-386).
Enterocytes are feasibly confronted with enormous zinc concentrations especially as a result of oral zinc supplementation. In the present study, we investigated the mechanisms underlying the exceptional ability to withstand this usually toxic load using the enterocytic cell line Caco-2.By MTT test analysis, we compared zinc tolerance in undifferentiated Caco-2 cells (udCaco-2) and differentiated Caco-2 cells (dCaco-2). By RT-PCR, we compared the respective baseline expression levels of certain zinc transporters and metallothioneins (MTs) as well as the regulation of these components in response to high zinc concentrations. Moreover, using dCaco-2 cells cultured on porous membranes, we explored zinc tolerance in dependence of the side of zinc administration: apical versus basolateral.dCaco-2 cells tolerate significantly higher levels of zinc compared to udCaco-2 cells. This adaptation was accompanied by upregulated ZnT-1 and downregulated ZIP1 levels. The expression of metallothioneins MT1A and MT1X was also significantly downregulated during differentiation. Moreover, apparent from profound differences in zinc tolerance between apical and basolateral zinc application, polarization was concluded to have substantial impact on cellular zinc tolerance.The profound increase in zinc tolerance we found in differentiated enterocyte-type Caco-2 cells and in particular, the impact of polarization are likely to reflect the physiologically indispensable capability of enterocytes to cope with remarkable concentrations of intestinal zinc.
Keywords: Zinc; Caco-2 cells; Zinc transporters; Metallothioneins; Differentiation

Low-dose lithium uptake promotes longevity in humans and metazoans by Kim Zarse; Takeshi Terao; Jing Tian; Noboru Iwata; Nobuyoshi Ishii; Michael Ristow (387-389).
Lithium is a nutritionally essential trace element predominantly contained in vegetables, plant-derived foods, and drinking water. Environmental lithium exposure and concurrent nutritional intake vary considerably in different regions. We here have analyzed the possibility that low-dose lithium exposure may affect mortality in both metazoans and mammals.Based on a large Japanese observational cohort, we have used weighted regression analysis to identify putative effects of tap water-derived lithium uptake on overall mortality. Independently, we have exposed Caenorhabditis elegans, a small roundworm commonly used for anti-aging studies, to comparable concentrations of lithium, and have quantified mortality during this intervention.In humans, we find here an inverse correlation between drinking water lithium concentrations and all-cause mortality in 18 neighboring Japanese municipalities with a total of 1,206,174 individuals (β = −0.661, p = 0.003). Consistently, we find that exposure to a comparably low concentration of lithium chloride extends life span of C. elegans (p = 0.047).Taken together, these findings indicate that long-term low-dose exposure to lithium may exert anti-aging capabilities and unambiguously decreases mortality in evolutionary distinct species.
Keywords: Trace elements; Lithium; Mortality; Longevity; Human; C. elegans