Stroke: roles of B vitamins, homocysteine and antioxidants.

In the present review concerning stroke, we evaluate the roles of B vitamins, homocysteine and antioxidant vitamins. Stroke is a leading cause of death in developed countries. However, current therapeutic strategies for stroke have been largely unsuccessful. Several studies have reported important benefits on reducing the risk of stroke and improving the post-stroke-associated functional declines in patients who ate foods rich in micronutrients, including B vitamins and antioxidant vitamins E and C. Folic acid, vitamin B6 and vitamin B12 are all cofactors in homocysteine metabolism. Growing interest has been paid to hyperhomocysteinaemia as a risk factor for CVD. Hyperhomocysteinaemia has been linked to inadequate intake of vitamins, particularly to B-group vitamins and therefore may be amenable to nutritional intervention. Hence, poor dietary intake of folate, vitamin B6 and vitamin B12 are associated with increased risk of stroke. Elevated consumption of fruits and vegetables appears to protect against stroke. Antioxidant nutrients have important roles in cell function and have been implicated in processes associated with ageing, including vascular, inflammatory and neurological damage. Plasma vitamin E and C concentrations may serve as a biological marker of lifestyle or other factors associated with reduced stroke risk and may be useful in identifying those at high risk of stroke. After reviewing the observational and intervention studies, there is an incomplete understanding of mechanisms and some conflicting findings; therefore the available evidence is insufficient to recommend the routine use of B vitamins, vitamin E and vitamin C for the prevention of stroke. A better understanding of mechanisms, along with well-designed controlled clinical trials will allow further progress in this area.

Common sources and estimated intake of plant sterols in the Spanish diet.

Plant sterols (PS) are minor lipid components of plants, which may have potential health benefits, mainly based in their cholesterol-lowering effect. The aim of this study was to determine the composition and content of PS in plant-based foods commonly consumed in Spain and to estimate the PS intake in the Spanish diet. For this purpose, the determination of PS content, using a modern methodology to measure free, esterified, and glycosidic sterol forms, was done. Second, an estimation of the intake of PS, using the Spanish National Food Consumption data, was made. The daily intake per person of PS--campesterol, beta-sitosterol, stigmasterol, and stigmastanol--in the Spanish diet was estimated at 276 mg, the largest component being beta-sitosterol (79.7%). Other unknown compounds, tentatively identified as PS, may constitute a considerable potential intake (99 mg). When the daily PS intake among European diets was compared in terms of campesterol, beta-sitosterol, stigmasterol, and stigmastanol, the PS intake in the Spanish diet was in the same range of other countries such as Finland (15.7% higher) or The Netherlands (equal). However, some qualitative differences in the PS sources were detected, that is, the predominant brown bread and vegetable fat consumption in the northern diets versus the white bread and vegetable oil consumption in the Spanish diet. These differences may help to provide a link between the consumption of PS and healthy effects of the diet.

In vitro antioxidant activities of edible artichoke (Cynara scolymus L.) and effect on biomarkers of antioxidants in rats.

Artichoke (Cynara scolymus L.), an edible vegetable from the Mediterranean area, is a good source of natural antioxidants such as vitamin C, hydroxycinnamic acids, and flavones. The antioxidant activity of aqueous-organic extracts of artichoke were determined using three methods: (a) free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH(*)) scavenging, (b) ferric-reducing antioxidant power (FRAP), and (c) inhibition of copper(II)-catalyzed in vitro human low-density lipoprotein (LDL) oxidation. In addition, the present study was performed to investigate the ability of the edible portion of artichoke to alter in vivo antioxidative defense in male rats using selected biomarkers of antioxidant status. One gram (dry matter) had a DPPH(*) activity and a FRAP value in vitro equivalent to those of 29.2 and 62.6 mg of vitamin C and to those of 77.9 and 159 mg of vitamin E, respectively. Artichoke extracts showed good efficiency in the inhibition in vitro of LDL oxidation. Neither ferric-reducing ability nor 2,2'-azinobis(3-ethylbenzothiazolin-6-sulfonate) radical scavenging activity was modified in the plasma of the artichoke group with respect to the control group. Among different antioxidant enzymes measured (superoxide dismutase, gluthatione peroxidase, gluthatione reductase, and catalase) in erythrocytes, only gluthatione peroxidase activity was elevated in the artichoke group compared to the control group. 2-Aminoadipic semialdehyde, a protein oxidation biomarker, was decreased in plasma proteins and hemoglobin in the artichoke-fed group versus the control group. In conclusion, the in vitro protective activity of artichoke was confirmed in a rat model.

Effects of Undaria pinnatifida, Himanthalia elongata and Porphyra umbilicalis extracts on in vitro α-glucosidase activity and glucose diffusion.

BACKGROUND: Seaweeds are good sources of dietary fibre, which can influence glucose uptake and glycemic control. OBJECTIVE: To investigate and compare the in vitro inhibitory activity of different extracts from Undaria pinnatifida (Wakame), Himanthalia elongata (Sea spaghetti) and Porphyra umbilicalis (Nori) on α-glucosidase activity and glucose diffusion. METHODS: The in vitro effects Chloroform-, ethanol- and water-soluble extracts of the three algae were assayed on α- glucosidase activity and glucose diffusion through membrane. Principal Components Analysis (PCA) was applied to identify patterns in the data and to discriminate which extract will show the most proper effect. RESULTS: Only water extracts of Sea spaghetti possessed significant in vitro inhibitory effects on α-glucosidase activity (26.2% less mmol/L glucose production than control, p < 0.05) at 75 min. PCA distinguished Sea spaghetti effects, supporting that soluble fibre and polyphenols were involved. After 6 h, Ethanol-Sea spaghetti and water-Wakame extracts exerted the highest inhibitory effects on glucose diffusion (65.0% and 60.2% vs control, respectively). This extracts displayed the lowest slopes for glucose diffusion-time lineal adjustments (68.2% and 62.8% vs control, respectively). CONCLUSIONS: The seaweed hypoglycemic effects appear multi-faceted and not necessarily concatenated. According to present results, ethanol and water extracts of Sea spaghetti, and water extracts of Wakame could be useful for the development of functional foods with specific hypoglycemic properties.

Antecedentes: Las algas son importante fuente alimentaria de fibra dietética y puede influir sobre la absorción de glucosa y el control glucémico. Objetivo: Evaluar y comparar in vitro los efectos de diferentes extractos de las algas Undaria pinnatifida (Wakame), Himanthalia elongata (Espagueti de mar) y Porphyra umbilicalis (Nori) sobre la actividad enzimática -glucosidasa y la difusión de glucosa. Métodos: Se estudiaron los efectos de los extractos clorofórmicos, etánólicos y acuosos de las tres algas sobre la actividad -glucosidasa y la difusión de glucosa a través de una membrana de diálisis. Se aplicó a los resultados un análisis de los componentes principales (PCA) para identificar posibles patrones de composición y seleccionar el extracto que mejores propiedades posea. Resultados: El extracto acuoso de Espagueti de mar inhibió de forma significativa la actividad -glucosidasa (26,2% menos liberación de glucosa, p < 0,05). El PCA sugiere que la fibra soluble y los polifenoles son los responsables de tal efecto. Respecto a la difusión de glucosa, el extracto etanólico de Espagueti de mar y el acuoso de Wakame mostraron un mayor efecto inhibidor después de 6 horas (65% y 60,2% vs control, respectivamente) y las menores pendientes en los ajustes lineales difusión de glucosa- tiempo (68,2% y 62,8% vs control respectivamente). Conclusiones: Los resultados de los diferentes extractos sugieren que los efectos hipogluceminates de las algas son variados y no están necesariamente concatenados. Los extractos acuosos y etanólicos de Espagueti de mar y los acuosos de Wakame parecen los más adecuados para el desarrollo de alimentos funcionales con propiedades hipoglucemiantes.

Effect of the red seaweed Mastocarpus stellatus intake on lipid metabolism and antioxidant status in healthy Wistar rats.

Health-promoting effect of dietary supplementation with the red seaweed Mastocarpus stellatus was studied. Its major component is dietary fibre (31.7/100 g dry weight), 72% as soluble fibre, mainly formed by carrageenans, sulphated-galactans of red seaweeds. Thus, rats were fed either a basal- or an algal-supplemented diet (10%). Then, lipid metabolism was assessed in serum, and reducing power measured in serum and caecum by FRAP method. Also, caecal pH was monitored and short chain fatty acids analysed by gas-liquid chromatography. Seaweed intake reduced significantly triglycerides and total cholesterol in healthy rats, but not atherogenic index. Also, a significant increase in caecal moisture and proportion of acetic and propionic acids was obtained but no clear prebiotic effect was shown. Sulphated-galactans seemed to be related to the antioxidant status improvement in caecum and also to the 1.7-fold increase in anticoagulant capacity of plasma. Therefore, Mastocarpus could be regarded as a source of functional ingredients but its health benefits need to be further explored depending on specific use.

Molecular weight distribution of polysaccharides from edible seaweeds by high-performance size-exclusion chromatography (HPSEC).

Biological properties of polysaccharides from seaweeds are related to their composition and structure. Many factors such as the kind of sugar, type of linkage or sulfate content of algal biopolymers exert an influence in the relationship between structure and function. Besides, the molecular weight (MW) also plays an important role. Thus, a simple, reliable and fast HPSEC method with refractive index detection was developed and optimized for the MW estimation of soluble algal polysaccharides. Chromatogram shape and repeatability of retention time was considerably improved when sodium nitrate was used instead of ultrapure water as mobile phase. Pullulan and dextran standards of different MW were used for method calibration and validation. Also, main polysaccharide standards from brown (alginate, fucoidan, laminaran) and red seaweeds (kappa- and iota-carrageenan) were used for quantification and method precision and accuracy. Relative standard deviation (RSD) of repeatability for retention time, peak areas and inter-day precision was below 0.7%, 2.5% and 2.6%, respectively, which indicated good repeatability and precision. Recoveries (96.3-109.8%) also showed its fairly good accuracy. Regarding linearity, main polysaccharide standards from brown or red seaweeds showed a highly satisfactory correlation coefficient (r>0.999). Moreover, a good sensitivity was shown, with corresponding limits of detection and quantitation in mg/mL of 0.05-0.21 and 0.16-0.31, respectively. The method was applied to the MW estimation of standard algal polysaccharides, as well as to the soluble polysaccharide fractions from the brown seaweed Saccharina latissima and the red Mastocarpus stellatus, respectively. Although distribution of molecular weight was broad, the good repeatability for retention time provided a good precision in MW estimation of polysaccharides. Water- and alkali-soluble fractions from S. latissima ranged from very high (>2400 kDa) to low MW compounds (<6 kDa); this high heterogeneity could be attributable to the complex polysaccharide composition of brown algae. Regarding M. stellatus, sulfated galactans followed a descending order of MW (>1400 kDa to <10 kDa), related to the different solubility of carrageenans in red seaweeds. In summary, the method developed allows for the molecular weight analysis of seaweed polysaccharides with very good precision, accuracy, linearity and sensitivity within a short time.

Effects of Undaria pinnatifida, Himanthalia elongata and Porphyra umbilicalis extracts on in vitro alpha-glucosidase activity and glucose diffusion / Efectos de extractos de undaria pinnatifida, himantalia elongata y porfira umbilicalis sobre la actividad alpha-glucosidasa y la difusion de la glucosa in vitro

Background: Seaweeds are good sources of dietary fibre, which can influence glucose uptake and glycemic control. Objective: To investigate and compare the in vitro inhibitory activity of different extracts from Undaria pinnatifida (Wakame), Himanthalia elongata (Sea spaghetti) and Porphyra umbilicalis (Nori) on α-glucosidase activity and glucose diffusion. Methods: The in vitro effects chloroform-, ethanol- and water-soluble extracts of the three algae were assayed on α- glucosidase activity and glucose diffusion through membrane. Principal Components Analysis (PCA) was applied to identify patterns in the data and to discriminate which extract will show the most proper effect. Results: Only water extracts of Sea spaghetti possessed significant in vitro inhibitory effects on α-glucosidase activity (26.2% less mmol/L glucose production than control, p < 0.05) at 75 min. PCA distinguished Sea spaghetti effects, supporting that soluble fibre and polyphenols were involved. After 6 h, Ethanol-Sea spaghetti and water-Wakame extracts exerted the highest inhibitory effects on glucose diffusion (65.0% and 60.2% vs control, respectively). This extracts displayed the lowest slopes for glucose diffusion-time lineal adjustments (68.2% and 62.8% vs control, respectively). Conclusions: The seaweed hypoglycemic effects appear multi-faceted and not necessarily concatenated. According to present results, ethanol and water extracts of Sea spaghetti, and water extracts of Wakame could be useful for the development of functional foods with specific hypoglycemic properties (AU)

Antecedentes: Las algas son importante fuente alimentaria de fibra dietética y puede influir sobre la absorción de glucosa y el control glucémico. Objetivo: Evaluar y comparar in vitro los efectos de diferentes extractos de las algas Undaria pinnatifida (Wakame), Himanthalia elongata (Espagueti de mar) y Porphyra umbilicalis (Nori) sobre la actividad enzimática α-glucosidasa y la difusión de glucosa. Métodos: Se estudiaron los efectos de los extractos clorofórmicos, etánólicos y acuosos de las tres algas sobre la actividad α-glucosidasa y la difusión de glucosa a través de una membrana de diálisis. Se aplicó a los resultados un análisis de los componentes principales (PCA) para identificar posibles patrones de composición y seleccionar el extracto que mejores propiedades posea. Resultados: El extracto acuoso de Espagueti de mar inhibió de forma significativa la actividad α-glucosidasa (26,2% menos liberación de glucosa, p < 0,05). El PCA sugiere que la fibra soluble y los polifenoles son los responsables de tal efecto. Respecto a la difusión de glucosa, el extracto etanólico de Espagueti de mar y el acuoso de Wakame mostraron un mayor efecto inhibidor después de 6 horas (65% y 60,2% vs control, respectivamente) y las menores pendientes en los ajustes lineales difusión de glucosa-tiempo (68,2% y 62,8% vs control respectivamente). Conclusiones: Los resultados de los diferentes extractos sugieren que los efectos hipogluceminates de las algas son variados y no están necesariamente concatenados. Los extractos acuosos y etanólicos de Espagueti de mar y los acuosos de Wakame parecen los más adecuados para el desarrollo de alimentos funcionales con propiedades hipoglucemiantes (AU)

Health-promoting effects of a dietary fiber concentrate from the soybean byproduct okara in rats.

Okara (a byproduct of the soy milk industry) is rich in proteins (24.5-37.5 g/100 g of dry matter (dm)), lipids (9.3-22.3 g/100 g of dm), and dietary fiber (DF) (14.5-55.4 g/100 g of dm). It also contains isoflavones (0.14 g/100 g of dm). In the present study we fed female healthy Wistar rats either a standard rat diet or a supplemented 10% DF-rich okara (DFRO) diet for 4 weeks, and then we assessed several health parameters in the serum and the cecum compartments. In comparison to the control group, rats fed DFRO showed a significant decrease in weight gain (5.00 +/- 1.22 g vs 2.00 +/- 1.46 g, P < 0.03, during week 4) and in total cholesterol (65 +/- 8 mg/dL vs 51 +/- 5 mg/dL, P < 0.05) and a significantly increased antioxidant status (36.71 +/- 15.31 micromol of Trolox equivalents (TEs)/g vs 69.75 +/- 16.11 micromol of TEs/g, P < 0.0003) and butyrogenic effect (39.37%, P < 0.003) in the cecum. In addition, a significant enhancement in the apparent absorption (41.89 +/- 1.64% vs 47.02 +/- 2.51%, P < 0.004) and in the true retention (41.62 +/- 1.60% vs 46.68 +/- 2.55%, P < 0.005) of calcium was appreciated. In summary, these findings show for the first time that a concentrate DF from a soybean byproduct protects the gut environment in terms of antioxidant status and prebiotic effect. These results may highlight the development of an innovative soybean byproduct rich in DF which could be useful as a functional ingredient with health-promoting attributes.

Effect of a blueberry nutritional supplement on macronutrients, food group intake, and plasma vitamin E and vitamin C in US athletes.

Antioxidants from a blueberry beverage may impact plasma vitamins. We examined vitamins/food selection in 12 college athletes during 30 days compared with placebo. Blood was collected before and after exercise at the beginning of the study (day 1) and then after a 30-day period of taking a daily supplemental beverage (day 30). The six trials involved blood that was drawn pre-beverage ingestion/pre-exercise (trials 1 and 4), post-beverage ingestion/pre-exercise (trials 2 and 5), and post-beverage ingestion/1 h post-exercise (trials 3 and 6), on day 1 (trials 1, 2, and 3) and day 30 (trials 4, 5, and 6). Analysis of variance revealed non-significant differences for macronutrient or gamma-tocopherol and vitamin C intakes by food frequency questionnaire or plasma vitamins by liquid chromatography. There was a trend (P = 0.083) in the group x time interaction for alpha-tocopherol intake by repeated-measures analysis of variance. Blueberry alpha-tocopherol (23.91 +/- 9.31 mg) was significantly (P < 0.05) higher than placebo alpha-tocopherol intake (7.59 +/- 0.95 mg) on day 1, but not on day 30 (blueberry, alpha-tocopherol = 9.04 +/- 2.35 mg, placebo, alpha-tocopherol = 11.46 +/- 3.65 mg) by pairwise comparisons. Blueberry supplementation did not affect plasma vitamin concentrations or gamma-tocopherol and vitamin C intakes, and may reduce alpha-tocopherol intake in those starting with a higher alpha-tocopherol intake, yet not altering athletes' eating habits.

Multifunctional in vitro antioxidant evaluation of strawberry (Fragaria virginiana Dutch.).

Berries have shown the highest potential antioxidant activity among fruits using a unique antioxidant method. The antioxidant activity of aqueous-organic extracts of strawberry (Fragaria virginiana Dutch., var. camarosa) were determined using three methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH*) radical scavenging, antioxidant ferric-reducing power (FRAP), and inhibition of Cu(II)-catalysed in vitro human low-density lipoprotein (LDL) oxidation. A serving (100 g) of strawberry had a DPPH* activity equivalent to that of 183 mg vitamin C and to that of 483 mg vitamin E. In addition, strawberry extracts showed high efficiency in the FRAP assay and in the in vitro inhibition of LDL oxidation. Regression linear analysis between radical scavenging activity (EC50 parameter) and total phenol content from strawberry extracts gave a statistically significant correlation (r = 0.984, P < 0.05). In conclusion, strawberry showed significant antioxidant capacity in both aqueous and lipophilic models.

Evaluación nutricional y efectos fisiológicos de macroalgas marinas comestibles / Nutricional evaluation and physiological effects of edible seaweeds

En este trabajo se realiza una revisión de las características nutricionales y efectos fisiológicos de macroalgas marinas comestibles. Las algas marinas son utilizadas tradicionalmente como alimento en la dieta oriental, siendo la obtención de ficocoloides industriales la principal utilización en el Occidente. Desde un punto de vista nutricional, son alimentos con un bajo contenido de calorías y lípidos, elevada concentración de minerales (Mg, Ca, K, P, I), vitaminas proteínas y carbohidratos indigeribles. La calidad de la proteína y de la grasa es bastante aceptable en comparación con otros alimentos de la dieta habitual, principalmente debido al elevado contenido en aminoácidos esenciales y a la concentración relativamente alta de ácidos grasos insaturados. El contenido en fibra dietética total oscila entre 33 por ciento y 75 por ciento del material seco, con un alto porcentaje de polisacáridos solubles (17 por ciento-59 por ciento). La fibra dietética presenta una composición distinta de la contenida en frutas, cereales y verduras, por lo que podría tener un comportamiento fisiológico diferente. Los datos revisados indican que algunos componentes de la fibra de algas marinas muestran acción antioxidante, antimutagénica y anticoagulante, así como efectos beneficiosos sobre el metabolismo lipídico. En conclusión, las algas tienen un alto valor nutricional, por lo que potenciar su consumo aumentaría la oferta de alimentos para la población