1,354,486 research outputs found
Bioavailability of carotenoids from spinach and tomatoes
No full textBackground and Aim: Few published studies have described the bioavailability of the different carotenoids in spinach. This was designed to evaluate the effects on plasma carotenoid concentrations of a daily consumption of spinach (rich in lutein and β-carotene), alone or together with lycopene-rich tomato puree. Methods and Results: Nine healthy young women consumed a standard low-carotenoid diet during the pre-study phase, the spinach diet (standard diet plus 150 g spinach: 9 mg lutein, 4 mg β-carotene) from day 0 to day 21, and then, after a wash-out period, the spinach-tomato diet (standard diet plus 150 g spinach and 25 g tomato puree: 9 mg lutein, 4.3 mg β-carotene and 7 mg lycopene) from day 35 to day 56. The spinach and spinach-tomato supplements were consumed together with 10 g olive oil. Fasting blood samples were collected on day -7, and every week thereafter. Plasma carotenoid concentrations significantly decreased during the standard low-carotenoid diet. Lutein levels gradually increased after spinach consumption from 0.36±0.05 to 1.59±0.19 μmol/L (p<0.0001), decreased during the wash-out period from 1.59±0.19 to 0.62±0.07 μmol/L (p<0.001), and rose again after the intake of spinach-tomato puree from 0.62±0.07 to 1.55±0.17 μmol/L (p<0.0001). β-carotene levels also increased during both dietary supplementation periods. Lycopene decreased during the spinach diet from 0.20±0.03 to 0.07±0.01 μmol/L (p<0.001) and increased during the spinach-tomato diet from 0.05±0.01 to 0.52±0.06 μmol/L (p<0.0001). Conclusions: The results of this study confirm that a regular intake of selected vegetables leads to a progressive increase in plasma carotenoid concentrations. The addition of tomato puree to spinach does not decrease lutein plasma concentrations. Furthermore, baseline plasma levels of lutein and lycopene are important variables affecting the relative increase in their levels after supplementation: ie more depleted subjects are expected to have a greater percent rise in plasma carotenoid concentrations
Urbanization effects on shoreline phytobenthos: A multiscale approach at lake extent
No full textTo understand how littoral biota respond to anthropogenic disturbances, limnologists seek to detect the scale at which patterns and processes occur. We conducted an extensive study on the shoreline phytobenthos of Lake Garda (Italy) with the following main objectives: (i) to examine the importance of urbanization for species distribution within a set of hierarchical spatial scales (101-104 m), and then (ii) to test the spatio-temporal interactions on a reduced set of scales (101-102 m, and 101-102 days). Results showed that most of the variation in most abundant species and habitat characteristics occurred at the spatial scale of 101-102 m. Species richness was positively related with microheterogeneity, but the relationship occurred only at low urbanization and not at highly-urbanized sites where artificial shores were less heterogeneous. The similarity of species assemblages was regulated by two interacting processes, one operating at a fine spatial scale (102 m), reflecting the physical-habitat requirements of the species, and the other one operating at a broader scale (104 m) in relation to the N-S nitrogen gradient. Overall, time explained 73 % of the total variation of species assemblages, space 7 %, and 20 % was explained by the interaction between space and time (the patch scale, 10s of m, and area scale, 100s of m, interacted with the finest temporal scale, 10s of days). This interaction might be explained by the process of species recruitment operating at different rates at the two spatial scales. Since the largest variation in species assemblages was at the temporal scale (due to the seasonal succession of phytobenthos), we recommend collecting at least one sample per season when monitoring littoral habitats. © 2013 Springer Basel
Niche partitioning, shape of species response, and diversity in the phytobenthos across the rocky shoreline of a large peri-Alpine lake
No full textBy colonizing a particular depth zone across the transition from aquatic to terrestrial habitats, littoral species may exhibit specific physiological and ecological adaptations, as well as characteristic responses to the gradient of conditions across the ecotone. The objectives of the study were: (i) to identify the depth zone (location in relation to average water level) where the replacement of species occurs most rapidly; (ii) to test whether and to what extent the occurrence of species, their abundance and their response to the gradient evolves over time; and (iii) to assess the shape of the species' response to the gradient, calculating the niche overlap of the dominant species. Results showed that the diversity of species peaked at a depth between 18 and 48. cm, in a zone thought to be of intermediate disturbance (the transect depth was, on average, 103. cm). The main macroalgal species (the red alga, Bangia atropurpurea and the green algae, Jaoa bullata, and Cladophora glomerata), showed a variety of response shapes to the gradient: monotonic, symmetrical and skewed, depending on the stage of seasonal growth. The efficient regulation of growth of B. atropurpurea along the fluctuating gradient was interpreted as an adaptive trait giving it an advantage over more slowly reacting species. The spatial and temporal niches of B. atropurpurea and Jaoa bullata overlapped widely only in early spring, whereas later their optimal habitats were clearly differentiated. This suggested partial niche segregation between these two species, and a potential seasonal interaction. © 2012 Elsevier B.V
Postprandial thermogenesis in lean and obese subjects after meals supplemented with medium-chain and long-chain triglycerides.
No full textABSTRACT
The thermic effect of medium-chain triglycerides (MCTs) was studied in six lean and six obese young males by evaluating postprandial thermogenesis (PPT) after the ingestion of mixed meals containing either 38 g long-chain triglycerides (LCTs) or 30 g MCTs plus 8 g LCTs. Postabsorptive resting metabolic rate (RMR) was higher (P less than 0.05) in the obese individuals than in the lean ones. PPT, evaluated as 6-h incremental areas above RMR, was greater (P less than 0.05) in both groups after meals containing MCTs. The thermic effect of MCTs was 119.7 +/- 33.9 and 144.7 +/- 48.8 kJ/6 h in the lean and the obese subjects, respectively. The postprandial response of glucose, insulin, and free fatty acids did not depend on the type of oil contained in the meal. Our study shows that PPT is enhanced in both lean and obese subjects when LCTs in a mixed meal are replaced with MCTs
Reduced cold-induced thermogenesis in familial human obesity.
No full textABSTRACT
It is well known that cold and diet-induced thermogenesis, which is mediated in small rodents by the hypothalamic-noradrenergic fibers-brown adipose tissue axis, is impaired in genetically obese mice. To test whether these adaptive mechanisms are also impaired in obese humans, 12 young males who were otherwise healthy (6 lean and 6 obese) were examined. The obese subjects had an early-onset type of obesity with a strong family history of it as well. Deep body temperature was measured by using a deep body thermometer furnished with three thermocouples. They were respectively placed on the sternum, on the interscapular area immediately under the neck (HIS), and on the 4th intercostal space (LIS) in order to study core temperature as well as heat production where brown adipose tissue could also be present in adults. Both lean and obese subjects were kept in a thermoneutral environment (28 degrees C) until they reached a steady-state body temperature and then rapidly transferred into a cold room (6-8 degrees C) where they remained up to 60 min. Body temperature decreased in both groups, but the decrease was more marked in the obese individuals on the sternum (P less than 0.01), on HIS (P less than 0.05) and on LIS (P less than 0.05) when compared to lean individuals. In conclusion, cold-induced thermogenesis is impaired in familial early-onset human obesity and in genetically obese mice
Whole grain and weight management: an intervention study to clarify underlying mechanisms
No full textINTRODUCTION: Epidemiological studies associate whole grain (WG) consumption to reduced CVD risk, body weight and abdominal circumference. Data obtained by intervention studies were not conclusive. Evidence from animal and few human studies indicated that prebiotic dietary fibre ameliorates metabolic syndrome and controls body weight through reduction of inflammation.
OBJECTIVES: This study aims i) to evaluate the effect of WG on body weight, circumferences and composition, ii) to clarify the underlying mechanisms.
DESIGN: A commercial WG product, having prebiotic properties and a high amount of polyphenols bound to dietary fibre, was selected. Eighty healthy overweight subjects will be enrolled. Forty volunteers will be asked to slightly change their habitual diet replacing equicaloric portions of specific foods with 68 g WG/die for 8 weeks; the other half will not change their diets. At baseline, and after 4 and 8 weeks, measure of body weight, waist and hip circumferences, bioimpedance analysis and blood, urine and feces collection will be performed. Markers linked to antioxidant status (serum ferulic acid, β-carotene and FRAP), to inflammatory status (several cytokines by multiplexed immunometric assay), to lipid and glucose metabolism as well as to the overall nutritional status and appetite, will be measured.
RESULTS: Preliminary data indicated that in subjects consuming WG, starting from 4 wk of treatment: i) both body weight and waist circumference were significantly reduced by 5% and 4% from baseline, respectively; ii) ferulic acid concentration was significantly doubled both in serum and urine, and triplicated in feces; iii) both fullness and satiety were doubled, while hunger did not vary from baseline.
CONCLUSIONS: The study is still ongoing but data obtained up to now indicated a good bioavailability of ferulic acid by WG consumption and encouraging perspectives as regards body weight management. The completion of protocol and analyses will permit to clarify the underlying mechanisms
Fine-Scale Spatial Patterns of Mature and Immature Filaments and Bioorganic Compounds of the Rhodophyte Bangia atropurpurea in the Supra- and Eulittoral Zones of a Large Lake
No full textBangia atropurpurea (Mertens ex Roth) C. Agardh is a freshwater red alga species that is distributed worldwide. B. atropurpurea is highly adaptable due to its stress-tolerance, which ensures survival under desiccation periods and under radiation extremes typical of the supra- and upper eulittoral zones. Whereas a number of previous investigations addressed some of the physiological and biochemical traits involved in stress-tolerance, we studied the spatial arrangement of the mature (multiseriate) and immature (uniseriate) filaments and of selected bioorganic compounds along a gradient defined by distance from the waterline. Substantial physiological and biochemical differences were previously observed among phenological stages in the marine environment. In this study, we showed a nonrandom spatial structure of both phenological stages and photosynthetic pigments and photoprotective compounds, R-phycocyanin and R-phycoerythrin along the supralittoral-eulittoral gradient. This observed pattern strongly suggests a complex interplay between physio-morphological regulation and spatial arrangement of mature and immature filaments in conferring the typical stress tolerance of B. atropurpurea. © 2012 Phycological Society of America
- …
