European Journal of Nutrition (v.52, #5)

Loss of skeletal muscle mass, also known as muscle wasting or muscle atrophy, is a common symptom of several chronic diseases, such as cancer and infectious diseases. Due to the strong negative impact of muscle loss on patient’s prognosis and quality of life, the development of efficacious treatment approaches to combat muscle wasting are of great importance. In order to evaluate the suitability of l-carnitine (LC) as an anti-wasting agent for clinical purposes the present review comprehensively summarizes the results from animal and clinical studies showing the effects of supplementation with LC or LC derivatives (acetyl-LC, propionyl-LC) on critical mechanisms involved in skeletal muscle loss under pathologic conditions, such as increased proteolysis, impaired protein synthesis, myonuclear apoptosis, inflammation, oxidative stress, and mitochondrial dysfunction.Evidence from both animal and clinical studies exists that LC supplementation causes an improved nitrogen balance either due to increased protein synthesis or reduced protein degradation, an inhibition of apoptosis and an abrogation of inflammatory processes under pathologic conditions. Furthermore, strong evidence has been provided, at least from animal studies, that LC supplementation prevents oxidative stress and ameliorates mitochondrial function, whereas results from a very low number of available clinical studies in this regard are inconclusive.In conclusion, LC supplementation beneficially influences several critical mechanisms involved in pathologic skeletal muscle loss that may at least partially explain the anti-catabolic effects and the improvement of fatigue-related parameters following LC supplementation in patients with chronic diseases. However, more suitable clinical trials (double-blinded, randomized, placebo-controlled, large-scale) are necessary in order to establish LC supplementation as strategy for anti-wasting therapy.
Keywords: l-carnitine; Muscle wasting; Cachexia; Proteolysis; Inflammation; Oxidative stress

Effects of 5 % weight loss through diet or diet plus exercise on cardiovascular parameters of obese: a randomized clinical trial by Ana Paula Trussardi Fayh; André Luiz Lopes; Antônio Marcos Vargas da Silva; Álvaro Reischak-Oliveira; Rogério Friedman (1443-1450).
To evaluate the effects of 5 % weight loss, through diet only or diet plus exercise, on lipid profile, inflammation and endothelial function in obese individuals.In this randomized clinical trial, 48 obese individuals were randomized to either a diet only group (DI) or a diet and exercise group (DI + EXE). Treatment was maintained until 5 % of the initial body weight was lost. At baseline and upon completion, the following parameters were analyzed: total cholesterol and fractions, triglycerides, fibrinogen, von Willebrand factor, high-sensitive C-reactive protein (hs-CRP) and endothelial function (brachial artery flow-mediated vasodilation—FMD).Thirteen individuals dropped out before completing the weight loss intervention. The median time required for reduction of 5 % of initial body weight was 79.7 days for the DI group and 65.9 days for the DI + EXE group (P = 0.16). In both DI (n = 18) and DI + EXE (n = 17), total cholesterol (−15.8 ± 4.8 and −10.5 ± 4.9 mg/dL, respectively), triglycerides (−33.8 ± 10.0 and −39.4 ± 10.3 mg/dL, respectively) and hs-CRP (−1.35 ± 0.41 and −0.45 ± 0.43 mg/L, respectively) decreased significantly, and in a similar response (repeated measures ANOVA). Weight loss did not change significantly the fibrinogen and FMD in both groups.A 5 % weight loss improves lipid profile and reduces inflammation in obese individuals. Endothelial function did not change significantly. Weight loss has a significant impact on these cardiovascular risk factors, and this is independent of physical training.
Keywords: Obesity; Lipid profile; Inflammation; Diet; Exercise

Confirmatory factor analysis to assess the measure of adiposity that best fits the diagnosis of metabolic syndrome and relationship to physical activity in adults by Manuel A. Gómez-Marcos; María C. Patino-Alonso; José I. Recio-Rodríguez; Juanjo Antón-Alvarez; Alfredo Cabrejas-Sánchez; Carmen Fernandez-Alonso; Javier Rubio-Galán; Verónica Arce; Luís García-Ortiz (1451-1459).
The objective of the study is to assess the goodness of fit for the diagnosis of metabolic syndrome in adults of four models with different measures of adiposity using confirmatory factor analysis, to develop a cardio metabolic risk index and to analyze its relationship to physical activity.Cross-sectional descriptive multicenter study including 636 patients from the EVIDENT study. Considering as fixed variables, triglycerides/HDL-C ratio, HOMA-IR index and mean arterial pressure, we will compare which single-factor model of metabolic syndrome shows better goodness of fit. The models only differ by the measure of adiposity used: waist circumference, waist circumference/height, body mass index or adiposity index. With the factorial weights obtained, we created a quantitative metabolic index and analyzed its relationship to physical activity, quantified with the accelerometer for 1 week and measured at counts/min.The single-factor model including waist circumference in women and body mass index in men were those that were better indicators of goodness of fit. The estimated quantitative metabolic index shows a mean value in men of −0.022 ± 1.29 with a range of values between −3.36 and 4.57 and in women of 0.0001 ± 1.53 with a range of values between −3.17 and 5.55. The quantitative index shows an inverse relationship to physical activity.Waist circumference in women and body mass index in men are the measures of adiposity that were better indicators goodness of fit. This quantitative index may be useful to quantify the risk of metabolic syndrome in clinical practice.
Keywords: Confirmatory Factor Analysis; Metabolic Syndrome; Adults; Physical Activity

Alpha-lipoic acid upregulates antioxidant enzyme gene expression and enzymatic activity in diabetic rat kidneys through an O-GlcNAc-dependent mechanism by Jelena Arambašić; Mirjana Mihailović; Aleksandra Uskoković; Svetlana Dinić; Nevena Grdović; Jelena Marković; Goran Poznanović; Djordje Bajec; Melita Vidaković (1461-1473).
The combined hyperglycemia lowering and antioxidant actions of α-lipoic acid (LA) contribute to its usefulness in preventing renal injury and other diabetic complications. The precise mechanisms by which LA alters diabetic oxidative renal injury are not known. We hypothesized that LA through its hypoglycemic effect lowers O-GlcNAcylation which influences the expression and activities of antioxidant enzymes which assume important roles in preventing diabetes-induced oxidative renal injury.An experimental model of diabetes was induced in rats by the administration of 40 mg/kg streptozotocin (STZ) intraperitoneally (i.p.) for five consecutive days. LA was applied at a dose of 10 mg/kg i.p. for 4 weeks, starting from the last day of STZ administration.An improved glycemic status of LA-treated diabetic rats was accompanied by a significant suppression of oxidative stress and a reduction of oxidative damage of lipids, proteins and DNA. LA treatment normalized CuZn-superoxide dismutase (SOD) and catalase activities in renal tissue of diabetic rats. These changes were allied with upregulated gene expression and lower levels of O-GlcNA glycosylation. The accompanying increase in MnSOD activity was only linked with upregulated gene expression. The observed antioxidant enzyme gene regulation was accompanied by nuclear translocation of Nuclear factor-erythroid-2-related factor 2 (Nrf2), enhanced expression of heat shock proteins (HSPs) and by reduction in O-GlcNAcylation of HSP90, HSP70, and extracellular regulated kinase and p38.α-Lipoic acid administration activates a coordinated cytoprotective response against diabetes-induced oxidative injury in kidney tissue through an O-GlcNAc-dependent mechanism.
Keywords: Diabetes; Kidney; α-Lipoic acid; O-GlcNAc modification; Antioxidant enzymes

Long-term effects of a neonatal low-protein diet in rats on the number of macrophages in culture and the expression/production of fusion proteins by Juliana Félix de Melo; Thacianna Barreto da Costa; Tamara D. da Costa Lima; Maria E. C. Chaves; Muriel Vayssade; Marie-Danielle Nagel; Célia M. M. B. de Castro (1475-1482).
To investigate the effects of a neonatal low-protein diet on the number of macrophages in culture and the expression/production of proteins that regulate macrophage fusion in young and adult rats.Male Wistar rats (n = 18) were suckled by mothers fed diets containing 17 % protein (controls, C) or 8 % protein (undernourished, UN). All rats were fed a normal protein diet after weaning. Bronchoalveolar lavage was collected from 42-, 60- and 90-day-old rats. Alveolar macrophages were cultured for 4 days to assess the number of cells and the expression of cadherins, key proteins involved in macrophage fusion, by western blotting. IL-4 and IFN-γ levels in culture supernatants were measured by ELISA.Offspring from mothers fed a low-protein diet showed a lower body weight gain. The number of cells in cultured macrophages from UN was reduced at 42 and 60 days and increased at 90 days. IL-4 production was increased in the supernatants from UN group at 60 days but did not affect the expression of cadherins. IFN-γ production was increased in the supernatants from UN group at 42 and 60 days and reduced at 90 days.This study thus demonstrated that dietary restriction during lactation altered the number of alveolar macrophages in culture and the production of fusion proteins of offspring aged 42, 60 or 90 days but did not modify the expression of adhesion molecules important for the fusion of these cells.
Keywords: Critical period of development; Programming; Macrophage fusion; Neonatal malnutrition

Modulation of CYP19 expression by cabbage juices and their active components: indole-3-carbinol and 3,3′-diindolylmethene in human breast epithelial cell lines by Barbara E. Licznerska; Hanna Szaefer; Marek Murias; Agnieszka Bartoszek; Wanda Baer-Dubowska (1483-1492).
The aim of this study was to evaluate the effect of white cabbage and sauerkraut juices of different origin and indole-3-carbinol (I3C) and diindolylmethane (DIM) on expression of CYP19 gene encoding aromatase, the key enzyme of estrogen synthesis.Human breast cell lines (MCF7, MDA-MB-231 and MCF10A) were examined to compare the action of cabbage juices versus their active components (I3C, DIM). Real-time PCR and Western blot were used in order to analyse CYP19 mRNA and protein, respectively.Remarkable differences in the effect on CYP19 transcript and protein level were found between the cabbage juices (in 2.5–25 mL/L concentrations) and indoles (in 2.5–50 μM doses) in the three cell lines. While cabbage juices at the lower doses diminished the aromatase expression in nontumorigenic/immortalized MCF10A breast cells (0.25–0.86-fold change, P < 0.05), I3C and DIM were more efficient in decreasing the aromatase expression in estrogen-dependant MCF7 breast cancer cells (0.24–0.82-fold change, P < 0.05). Inhibition of aromatase by juice obtained from cabbage grown on industrial farm was correlated with the induction of apoptosis (1.7–1.8-fold change, P < 0.01) in MCF10A cells. In estrogen-independent MDA-MB-231 cells, up-regulation of CYP19 expression by I3C and DIM (1.5–2.0-fold change, P < 0.05) was observed. Similarly, in MCF7 cells juices increased aromatase expression (1.1–2.2-fold change, P < 0.05).These results, particularly that obtained in nontumorigenic/immortalized MCF10A cells, suggest that chemopreventive activity of cabbage against breast cancer observed in epidemiological studies may be partly explained by inhibition of the aromatase expression.
Keywords: CYP19; Cabbage juices; Indole-3-carbinol; Diindolylmethane; Apoptosis; Breast cancer chemoprevention

Factors associated with serum/plasma concentrations of vitamins A, C, E and carotenoids in older people throughout Europe: the EUREYE study by J. V. Woodside; I. S. Young; S. E. C. M. Gilchrist; J. Vioque; U. Chakravarthy; P. T. V. M. de Jong; M. Rahu; J. Seland; G. Soubrane; L. Tomazzoli; F. Topouzis; J. R. Vingerling; A. E. Fletcher (1493-1501).
To report on plasma/serum levels of antioxidant vitamin and carotenoids in older adults resident in multiple countries in Europe and examine relationships with potential modifiers.Population-based cross-sectional European Eye Study in 7 centres from northern to southern Europe. In total, 4,133 participants aged 65 years or over, collected by random sampling, were recruited. Questionnaires relating to diet, lifestyle and medical history were administered. Non-fasting blood samples were analysed in a single laboratory for vitamins A, C and E and a panel of carotenoids. Associations were analysed by bootstrapped multivariable regression analysis.Centre and season influenced the serum and plasma concentrations of all antioxidant vitamins and carotenoids. Gender, BMI, smoking, age, education, alcohol consumption and supplement use were also significantly associated with some, but not all, of the antioxidant vitamins and carotenoids examined. The proportion of variance explained ranged from 4.8 % for retinol to 25.2 % for zeaxanthin.In older people, antioxidant vitamin and carotenoid status varies by centre and season, but is also associated with other behavioural and lifestyle variables. Studies aiming to demonstrate an association between antioxidant vitamins and carotenoid status and chronic disease risk should consider these potential confounders.
Keywords: Antioxidant vitamin; Carotenoids; Older people; Lifestyle factors; Confounding factors

Challenges in estimating the validity of dietary acrylamide measurements by Pietro Ferrari; Heinz Freisling; Eric J. Duell; Rudolf Kaaks; Leila Lujan-Barroso; Françoise Clavel-Chapelon; Marie-Christine Boutron-Ruault; Laura Nailler; Silvia Polidoro; Amalia Mattiello; Domenico Palli; Rosario Tumino; Sara Grioni; Sven Knüppel; Anne Tjønneland; Anja Olsen; Kim Overvad; Philippos Orfanos; Michail Katsoulis; Antonia Trichopoulou; Jose Ramón Quirós; Eva Ardanaz; José María Huerta; Pilar Amiano Etxezarreta; María José Sánchez; Francesca Crowe; Kay-Tee Khaw; Nicholas J. Wareham; Marga Ocke; Bas Bueno-de-Mesquita; Petra H. M. Peeters; Ulrika Ericson; Elisabet Wirfält; Göran Hallmans; Ingegerd Johansson; Dagrun Engeset; Geneviève Nicolas; Valentina Gallo; Teresa Norat; Elio Riboli; Nadia Slimani (1503-1512).
Acrylamide is a chemical compound present in tobacco smoke and food, classified as a probable human carcinogen and a known human neurotoxin. Acrylamide is formed in foods, typically carbohydrate-rich and protein-poor plant foods, during high-temperature cooking or other thermal processing. The objectives of this study were to compare dietary estimates of acrylamide from questionnaires (DQ) and 24-h recalls (R) with levels of acrylamide adduct (AA) in haemoglobin.In the European Prospective Investigation into Cancer and Nutrition (EPIC) study, acrylamide exposure was assessed in 510 participants from 9 European countries, randomly selected and stratified by age, sex, with equal numbers of never and current smokers. After adjusting for country, alcohol intake, smoking status, number of cigarettes and energy intake, correlation coefficients between various acrylamide measurements were computed, both at the individual and at the aggregate (centre) level.Individual level correlation coefficient between DQ and R measurements (r DQ,R) was 0.17, while r DQ,AA and r R,AA were 0.08 and 0.06, respectively. In never smokers, r DQ,R, r DQ,AA and r R,AA were 0.19, 0.09 and 0.02, respectively. The correlation coefficients between means of DQ, R and AA measurements at the centre level were larger (r > 0.4).These findings suggest that estimates of total acrylamide intake based on self-reported diet correlate weakly with biomarker AA Hb levels. Possible explanations are the lack of AA levels to capture dietary acrylamide due to individual differences in the absorption and metabolism of acrylamide, and/or measurement errors in acrylamide from self-reported dietary assessments, thus limiting the possibility to validate acrylamide DQ measurements.
Keywords: Acrylamide; Dietary questionnaires; Haemoglobin adducts; Biomarkers; Smoking; Measurement errors

Riboflavin is an essential component of the human diet, with an established role for its derivative cofactors in oxidative metabolism. Our previous in vivo data suggest that riboflavin may act as a signalling molecule in the intestinal lumen, regulating crypt development and cell turnover. Our in vitro studies in riboflavin-depleted intestinal cells in culture indicate that riboflavin depletion impairs normal mitosis.The aim of the study was to establish an improved intestinal cell model of riboflavin depletion using the structural analogue of riboflavin, lumiflavin (7,8,10-trimethyl-isoalloxazine) and to determine effects on cell function. The study was conducted using three intestinal cell lines, Caco-2, HCT116 and HT29 cells.Cell growth was inhibited in all three cell lines, in a lumiflavin concentration-dependent manner. Riboflavin depletion was confirmed through a significant decrease in intracellular riboflavin concentrations in Caco-2 and HT29 cell lines and a significant increase in the activation coefficient for the flavin adenine dinucleotide-dependent enzyme glutathione reductase. Riboflavin depletion led to a significant reduction in intracellular ATP concentration, and an enhanced generation of reactive oxygen species was also observed in response to riboflavin depletion, in all cell lines; effects were at least fivefold greater in Caco-2 cells than other cells. Riboflavin-depleted Caco-2 and HCT116 cells also showed an irreversible loss of proliferative potential.A model system of intracellular riboflavin depletion in intestinal epithelial cells has been developed. Riboflavin depletion induced by lumiflavin results in oxidative stress and a disruption of energy generation, which may contribute to observed effects on cell proliferation.
Keywords: Riboflavin deficiency; Lumiflavin; Intestinal epithelial cells; ATP; ROS; Clonogenicity

The aim of this study was to determine the effects of an atherogenic diet (AD; 40 % lipid, 1.25 % cholesterol, kcal) on triglyceride (TAG) and cholesterol accumulation in liver and on gene expression of liver X receptor (LXR) and farnesoid X receptor (FXR) and their target genes and to observe if these responses are affected by endurance training.Sprague–Dawley rats (n = 32) were divided into two groups and randomly assigned to an AD or a standard diet (SD) for 7 weeks. Half of the rats in each group were assigned to an exercise training program for 5 days/week.The AD resulted in a large (P < 0.01) accumulation in liver TAG (4×) along with elevated liver and plasma cholesterol without any gain in peripheral fat mass. The liver TAG and cholesterol accumulations were associated with an important reduction (P < 0.01; 60 %) in FXR, but no change in LXR transcripts. Accompanying the reduction in FXR gene expression, we found an increase (P < 0.001) in SREBP-1c and a decrease (P < 0.01) in MTP mRNAs suggesting an increased lipogenesis and a reduced VLDL production, respectively. The AD was also associated with lower HMG-CoA-r, squalene synthase, and ABCG8 transcripts (P < 0.001). In the intestine, exercise training resulted in higher NPC1L1, ABCG5, and ABCG8 in SD-fed animals, while all these increases were suppressed under the AD feeding.It is concluded that dietary cholesterol favors liver TAG and cholesterol accumulations associated with an important reduction in FXR transcripts.
Keywords: Cholesterol transport; Bile acid synthesis; Liver cholesterol; Exercise

Blood glucose concentrations and breast cancer risk in women without diabetes: a meta-analysis by Peter Boyle; Alice Koechlin; Cécile Pizot; Mathieu Boniol; Chris Robertson; Patrick Mullie; Geremia Bolli; Julio Rosenstock; Philippe Autier (1533-1540).
Some studies have suggested an increased risk of breast cancer associated with elevated fasting serum glucose in nondiabetic subjects. Given how common both breast cancer and impaired glucose tolerance are in our aging societies, this is an important issue for public health.We performed a systematic review of prospective cohort studies that examined the association between elevated serum glucose levels in nondiabetic subjects (levels below 7.0 mml/L) and the subsequent risk of breast cancer. We performed a systematic literature search and extracted relevant data in a standard way. We then computed summary relative risks (SRR) and 95 % confidence intervals using a random effects model applied on the risk of highest versus lowest quantile of serum glucose concentrations.Ten cohort studies were retrieved. The SRR for all studies was 1.11 (1.00–1.23), with no evidence of heterogeneity or publication bias. The SRR was not affected when the analysis was restricted to the 8 studies that reported results for fasting subjects (SRR = 1.11; 95 % CI 0.98–1.25). Three studies provided BMI-unadjusted and BMI-adjusted SRRs of 1.24 (95 % CI 0.60–2.56) and 1.20 (95 % CI 0.63–2.27), respectively. Similar magnitudes of associations were observed in sensitivity analyses, but statistical significance was lost.In nondiabetic subjects, the risk of breast cancer associated with fasting serum glucose levels seems to be small. Potential limitations to this meta-analysis include the fact that not all studies reported risks adjusted for adiposity and that serum glucose levels of comparison groups were variable across studies.
Keywords: Fasting glucose; Diabetes; Breast cancer; Meta-analysis

We investigated effects of ground whole flaxseed supplementation on erythrocyte polyunsaturated fatty acids (PUFAs) and serum biomarkers of inflammation, endothelial dysfunction, oxidative stress, and thrombosis in Chinese with risk factors of metabolic syndrome (MetS).This study was a secondary analysis of a 12-week, randomized, parallel-group trial in participants screened for MetS. The analysis included only those with 2 or more components of MetS before receiving either lifestyle counseling (LC, n = 90) or LC + 30 g/day flaxseed supplementation (LCF, n = 83).Compared to the LC group, those in the LCF group experienced significant increases in total erythrocyte n-3 PUFAs, α-linolenic acid, eicosapentenoic acid, and docosapentenoic acid (all P < 0.001), while total n-6 PUFAs (P < 0.05) and n-6/n-3 ratio decreased (P < 0.001). Arachidonic acid increased significantly in the LC group (P < 0.001), and serum high-sensitivity C-reactive protein, interleukin-18, soluble intracellular adhesion molecular-1, E-selectin, and plasminogen activator inhibitor-1 declined significantly in both groups (all P < 0.05), but no between-group differences were observed. There was no significant change in serum interleukin-6, tumor necrosis factor-α, soluble vascular adhesion molecular-1, monocyte chemoattractant protein-1, and oxidized low-density lipoprotein in either group.These data suggest that flaxseed supplementation increases erythrocyte n-3 PUFAs, decreases n-6 PUFAs and n-6/n-3 ratio in participants with risk factors of MetS, but has no additional benefits beyond the lifestyle consulting for the multiple biomarkers tested in the current study.
Keywords: Flaxseed; PUFA; Cytokines; Metabolic syndrome