M. Angeles Zulet

Reactive species and diabetes: counteracting oxidative stress to improve health.

Oxidative stress is at the very core of metabolism. Reactive species behave as true second messengers that control important cellular functions. However, under pathological conditions, abnormally large concentrations of these species may lead to permanent changes in signal transduction and gene expression. Attenuation of oxidative stress as a way to improve several diseases such as diabetes has flourished as one of the main challenges of research. The lack of evidence to prove the benefits from antioxidant compounds has led to boost these strategies. Inhibition of reactive oxygen species (ROS) production through the development of inhibitors against NADPH oxidase and mitochondria offers an alternative approach to conventional antioxidant therapies. There is a need to understand oxidative stress process to implement health-disorder approaches.

Dietary total antioxidant capacity is negatively associated with some metabolic syndrome features in healthy young adults

OBJECTIVE Oxidative stress has been related to the development of obesity and other features accompanying chronic diseases. Furthermore, dietary antioxidant intake has been suggested to protect against oxidative damage and related clinical complications. Therefore, the aim of this study was to assess the potential associations among dietary total antioxidant capacity (TAC) and several early metabolic syndrome manifestations in healthy young adults. METHODS Anthropometric variables and blood pressure from 153 healthy subjects (20.8+/-2.7 y old) were measured. Dietary intake was assessed by a validated food-frequency questionnaire and a 3-d record, which were also used to calculate TAC and to adjust by daily energy intake. Fasting blood samples were collected for measuring biochemical markers. RESULTS Dietary TAC showed positive and significant associations with fiber, folic acid, vitamin A and C, magnesium, selenium, and zinc intakes, after adjusting by sex and daily energy intake. Interestingly, systolic blood pressure, serum glucose, and free fatty acids were also found to be negatively associated with dietary TAC independently of sex and daily energy intake. Also, a relevant relation was found between body mass index and TAC values. Interestingly, after adjusting by sex and daily energy intake, complement factor-3 circulating levels appeared to be negatively and significantly associated with dietary TAC, whereas blood plasminogen activator inhibitor-1 and homocysteine concentrations showed an inverse marginally statistical trend. CONCLUSIONS These data suggest that dietary TAC may be also a potential early estimate of the risk to develop metabolic syndrome features and that dietary TAC could be a useful research tool in assessing antioxidant intake.

Effects of the whole seed and a protein isolate of faba bean ( Vicia faba ) on the cholesterol metabolism of hypercholesterolaemic rats

The aim of the present work was to analyse the hypocholesterolaemic efficiency of a Vicia faba-protein isolate in relation to the intact legume. In addition, the mechanisms underlying the effects of this isolate were investigated. Hypercholesterolaemic rats were divided into three groups and fed high-fat diets rich in cholesterol-containing casein, whole seeds of Vicia faba or the protein isolate of faba beans as protein source, for 2 weeks ad libitum. The protein isolate was prepared by isoelectric precipitation and spray dried. Analyses of serum, liver and faeces, as well as of the activity of hepatic 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase, were assessed by enzymatic methods. The rats fed on Vicia faba diets showed significantly lower body weights and energy intakes than rats fed on casein diets. The whole-seed diet induced a significant reduction in plasma triacylglycerol. Feeding rats on diets containing faba bean seeds, or the protein isolate, induced a significant decrease in plasma (LDL+VLDL)-cholesterol but not in HDL-cholesterol. Hepatic cholesterol and triacylglycerol were also reduced. The hypocholesterolaemic effects of Vicia faba were not the result of a reduction in cholesterol synthesis as assessed from HMG-CoA reductase activity, but the result of an increase in steroid faecal excretion. The faba bean-protein isolate obtained under our experimental conditions was useful in improving the metabolic alterations induced by feeding with a hypercholesterolaemic diet compared with casein. The effectiveness of the whole seeds was higher than that of the protein isolate.

Dietary total antioxidant capacity is inversely related to central adiposity as well as to metabolic and oxidative stress markers in healthy young adults

BackgroundDietary total antioxidant capacity (TAC) has been assumed as a useful tool to assess the relationship between the cumulative antioxidant food capacity and several chronic disorders. The aim of this cross-sectional study was to investigate the potential relationships of dietary TAC with adiposity, metabolic and oxidative stress markers in healthy young adults.MethodsThis study enrolled 266 healthy subjects (105 men/ 161 women; 22 ± 3 years-old; 22.0 ± 2.7 kg/m2). Dietary intake, anthropometry, blood pressure, lifestyle features, and biochemical data were assessed with validated procedures.ResultsIn linear regression analyses, dietary TAC values were inversely associated with glycemia, total cholesterol:HDL-c ratio, triglycerides and oxidized-LDL concentrations, and positively associated with HDL-c concentrations, independently of gender, age, smoking status, physical activity, vitamin use supplement, waist circumference, energy intake, fatty acid intake. In addition, plasma TAC was negatively correlated with ox-LDL concentrations (r= -0.20, P = 0.003), independently of the assessed confounding variables. Finally, dietary TAC values were inversely related to waist circumference values (r= -0.17, P = 0.005) as well as to lower mild central obesity occurrence (waist circumference ≥ 80/ 94 cm for women/ men, respectively).ConclusionDietary TAC values are inversely associated with glucose and lipid biomarkers as well as with central adiposity measurements in healthy young adults, indicating dietary TAC as a useful tool to assess the health benefits of cumulative antioxidant capacity from food intake. In addition, the independent and inverse relationships of ox-LDL concentrations with dietary and plasma TAC respectively suggest a putative role of antioxidant rich-diet in the link between redox state and atherogenesis at early stage.

Dietary Total Antioxidant Capacity: A Novel Indicator of Diet Quality in Healthy Young Adults

Background: Overall diet quality measurements have been suggested as a useful tool to assess diet-disease relationships. Oxidative stress has been related to the development of obesity and other chronic diseases. Furthermore, antioxidant intake is being considered as protective against cell oxidative damage and related metabolic complications. Objective: To evaluate potential associations between the dietary total antioxidant capacity of foods (TAC), the energy density of the diet, and other relevant nutritional quality indexes in healthy young adults. Methods: Several anthropometric variables from 153 healthy participants (20.8 ± 2.7 years) included in this study were measured. Dietary intake was assessed by a validated food-frequency questionnaire, which was also used to calculate the dietary TAC and for daily energy intake adjustment. Results: Positive significant associations were found between dietary TAC and Mediterranean energy density hypothesis–oriented dietary scores (Mediterranean Diet Score, Alternate Mediterranean Diet Score, Modified Mediterranean Diet Score), non-Mediterranean hypothesis–oriented dietary scores (Healthy Eating Index, Alternate Healthy Eating Index, Diet Quality Index-International, Diet Quality Index-Revised), and diversity of food intake indicators (Recommended Food Score, Quantitative Index for Dietary Diversity in terms of total energy intake). The Mediterranean Diet Quality Index and Diet Quality Index scores (a Mediterranean and a non–Mediterranean hypothesis–oriented dietary score, respectively), whose lower values refer to a higher diet quality, decreased with higher values of dietary TAC. Energy density was also inversely associated with dietary TAC. Conclusion: These data suggest that dietary TAC, as a measure of antioxidant intake, may also be a potential marker of diet quality in healthy subjects, providing a novel approach to assess the role of antioxidant intake on health promotion and diet-based therapies.

Short-term role of the dietary total antioxidant capacity in two hypocaloric regimes on obese with metabolic syndrome symptoms: the RESMENA randomized controlled trial.

BackgroundDietary strategies seem to be the most prescribed therapy in order to counteract obesity regarding not only calorie restriction, but also bioactive ingredients and the composition of the consumed foods. Dietary total antioxidant capacity (TAC) is gaining importance in order to assess the quality of the diet.MethodsNinety-six obese adults presenting metabolic syndrome (MetS) symptoms completed an 8-week intervention trial to evaluate the effects of a novel dietary program with changes in the nutrient distribution and meal frequency and to compare it with a dietary pattern based on the American Heart Association (AHA) guidelines.Anthropometric and biochemical parameters were assessed at baseline and at the endpoint of the study, in addition to 48-hours food dietary records.ResultsBoth diets equally (p > 0.05) improved MetS manifestations. Dietary TAC was the component which showed the major influence on body weight (p = 0.034), body mass index (p = 0.026), waist circumference (p = 0.083) and fat mass (p = 0.015) reductions. Transaminases (ALT and AST) levels (p = 0.062 and p = 0.004, respectively) were associated with lower TAC values.ConclusionRESMENA diet was as effective as AHA pattern for reducing MetS features. Dietary TAC was the most contributing factor involved in body weight and obesity related markers reduction.Trial registrationhttp://www.clinicaltrials.gov; NCT01087086

Dietary selenium intake is negatively associated with serum sialic acid and metabolic syndrome features in healthy young adults

Low-grade and chronic inflammation related to excessive body weight can increase the risk for type 2 diabetes and cardiovascular disease, whereas the intake of antioxidant nutrients appears to produce anti-inflammatory effects. The purpose of this observational study was to assess the potential relationships between serum SA levels, metabolic syndrome features, and dietary selenium intake to test the hypothesis that this antioxidant micronutrient may also have anti-inflammatory properties in healthy young adults. Forty-three healthy participants with a mean age of 18.0 +/- 0.93 years and a mean body mass index of 22.2 +/- 2.7 kg/m(2) were enrolled. Anthropometric, body composition, and blood pressure determinations were measured as well as serum lipid profile, glucose, insulin, and SA concentrations. Nutritional intake was estimated by a computerized, validated semiquantitative food frequency questionnaire. The findings included a positive correlation between SA and triacylglycerol levels (r = 0.317, P = .038) and a trend to significance with the homeostatic model assessment of insulin resistance index (r = 0.297, P = .053). Moreover, subjects with higher dietary selenium intake showed statistically lower SA levels compared with subjects with lower dietary selenium intake (1.8 +/- 0.4 vs 2.1 +/- 0.4 mmol/L, P = .037), while dietary selenium negatively correlated with SA (r = -0.331, P = .030) and triacylglycerol levels (r = -0.312, P = .041). It can be concluded that a relationship of SA, an inflammatory marker, with metabolic syndrome features such as lipid profile impairment and insulin resistance has been envisaged. In addition, we report (apparently for the first time) a negative association between SA and selenium intake, a recognized antioxidant trace element, in healthy young subjects, reinforcing the view of selenium as a potential anti-inflammatory nutrient.

Association of retinol-binding protein-4 with dietary selenium intake and other lifestyle features in young healthy women

OBJECTIVE This study specifically assessed plasma retinol-binding protein-4 (RBP4), an inflammatory marker, in young healthy women, with emphasis on its potential relations to dietary intake and lifestyle features. METHODS Seventy-four women with a mean age of 20.5 +/- 2.5 y and body mass index of 21.3 +/- 2.3 kg/m(2) were enrolled. Anthropometric, blood pressure, glucose, lipid profile, RBP4, and insulin concentrations were determined. Nutritional intakes were estimated by a validated semiquantitative food-frequency questionnaire. Physical activity and smoking status were evaluated with appropriate tools. RESULTS Regarding anthropometric and biochemical variables, only triacylglycerol concentration had a positive and significant association with plasma RBP4 concentrations (P < 0.001). Trans fatty acid intake, vitamin A intake, and smoking time showed positive and significant correlations with RBP4 concentrations (P < 0.05). Furthermore, individuals with a higher selenium intake (P = 0.027), non-smoking participants (P = 0.032), and subjects who self-declared to practice some physical activity (P = 0.030) presented significantly lower RBP4 concentrations. Interestingly, selenium intake was inversely and significantly associated with RBP4 concentration (P = 0.018) when adjusted for smoking status, energy intake, and vitamin C, vitamin E, and zinc intakes. Plasma RBP4 concentrations were also associated with smoking status (P = 0.035), adjusted for potential confounding factors. CONCLUSION This translational research revealed that dietary intake of a nutrient with an impact on oxidative stress such as selenium and lifestyle features such as smoking habit can modulate RBP4 concentrations. Our results suggest that plasma RBP4 values could be a valuable tool to screen potential nutrient and inflammation interactions.

Bioactive compounds with effects on inflammation markers in humans.

Obesity and other chronic diseases are accompanied by adipose tissue, liver, pancreas, muscle and brain low-grade chronic inflammation. Indeed, the obese condition and metabolic syndrome are characterized by an increased expression of inflammatory cytokines and infiltration of immune cells in adipocytes. The inflammatory response promotes the activation of transcriptional factors and pro-inflammatory cytokines, which can lead to an unresolved inflammatory response associated with an inhibition of insulin signalling and high risk for cardiovascular events. Epidemiological and intervention studies have been carried out to find out dietary patterns, foods and bioactive compounds with protective anti-inflammatory actions. The most studied compounds are polyphenols, especially isoflavone and anthocyanin, but quercertin, catechin and resveratrol have also been investigated. Furthermore, some studies have reported the effects of milk peptides, plant sterol and stanol, l-carnitine and α-lipoic acid on inflammatory processes. This review aimed to collect and discuss those relevant studies reported in the scientific literature following a systematic scientific search about the effect of such bioactive compounds on inflammation in humans.

A new dietary strategy for long-term treatment of the metabolic syndrome is compared with the American Heart Association (AHA) guidelines: the MEtabolic Syndrome REduction in NAvarra (RESMENA) project

The long-term effects of dietary strategies designed to combat the metabolic syndrome (MetS) remain unknown. The present study evaluated the effectiveness of a new dietary strategy based on macronutrient distribution, antioxidant capacity and meal frequency (MEtabolic Syndrome REduction in NAvarra (RESMENA) diet) for the treatment of the MetS when compared with the American Heart Association guidelines, used as Control. Subjects with the MetS (fifty-two men and forty-one women, age 49 (se 1) years, BMI 36·11 (se 0·5) kg/m²) were randomly assigned to one of two dietary groups. After a 2-month nutritional-learning intervention period, during which a nutritional assessment was made for the participants every 15 d, a 4-month self-control period began. No significant differences were found between the groups concerning anthropometry, but only the RESMENA group exhibited a significant decrease in body weight ( - 1·7%; P= 0·018), BMI ( - 1·7%; P= 0·019), waist circumference ( - 1·8%; P= 0·021), waist:hip ratio ( - 1·4%; P= 0·035) and android fat mass ( - 6·9%; P= 0·008). The RESMENA group exhibited a significant decrease in alanine aminotransferase and aspartate aminotransferase (AST) concentrations ( - 26·8%; P= 0·008 and - 14·0%; P= 0·018, respectively), while the Control group exhibited a significant increase in glucose (7·9%; P= 0·011), AST (11·3%; P= 0·045) and uric acid (9·0%; P< 0·001) concentrations. LDL-cholesterol (LDL-C) concentrations were increased (Control group: 34·4%; P< 0·001 and RESMENA group: 33·8%; P< 0·001), but interestingly so were the LDL-C:apoB ratio (Control group: 28·7%; P< 0·001, RESMENA group: 17·1%; P= 0·009) and HDL-cholesterol concentrations (Control group: 21·1%; P< 0·001, RESMENA group: 8·7; P= 0·001). Fibre was the dietary component that most contributed to the improvement of anthropometry, while body-weight loss explained changes in some biochemical markers. In conclusion, the RESMENA diet is a good long-term dietary treatment for the MetS.