Food habits and nutritional status of elderly people living in a Spanish Mediterranean city.

AIMS: The aim of this study was to assess the food habits and nutritional status of free-living, non-institutionalised, elderly people of Torrevieja, a Spanish city located in the Mediterranean coast. METHODS: Anthropometric and dietary survey (two 24 hour recalls) were assessed in 200 (83 men and 117 women) free-living elderly people (average age 72.3±6.6 years). RESULTS: Just married women accomplished the recommended energy intake. The contribution of macronutrients to the total energy intake was different from the Recommended Intake for the elderly, since it was too derived from proteins, fats, SFA and sugars, but in only small amounts was derived from complex carbohydrates. High percentages of elderly persons showed inadequate intake of calcium, zinc, magnesium, potassium, copper, iodine, folic acid, vitamin A, vitamin D, vitamin E, and riboflavin. Men showed lower micronutrient intake than women. CONCLUSIONS: An increase in dietary complex carbohydrate, and a decrease in protein and fats, especially SFA, is recommended. It would be desirable to increase the consumption of fruits, vegetables, whole cereals, fish and skimmed dairy products.

Development of a dual-analyte fluorescent sensor for the determination of bioactive nitrite and selenite in water samples.

Nitrite and selenium are two bioactive compounds found in the environment which show beneficial effects for health at low levels but have toxic effects at higher doses. Consequently, quantification of both analytes in water samples results of great interest in areas such as biomedicine, food technology and environmental analysis. In a recent paper, we immobilized the inclusion complex formed between 2,3-diaminonaphthalene (DAN) and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) in a sol-gel matrix, in order to prepare a highly sensitive reagentless fluorescence-based sensor for the specific measurement of nitrite. Here we have explored the possibility of using the sol-gel immobilized complex to quantify selenite (Se (IV)), the more toxic form of selenium, as well as to act as a dual-analyte chemical sensor for simultaneous quantification of both nitrite and selenite in aqueous samples. Results show that (a) inclusion of DAN in HP-beta-CD and its subsequent immobilization in a sol-gel matrix do not modify the reactivity of DAN against selenite, (b) the reaction product formed (4,5-benzopiazselenol) remains into the cyclodextrin increasing considerably its fluorescence quantum yield and avoiding, therefore, its extraction into organic solvents, (c) the developed sensor can detect selenite concentrations at submicromolar level with a minimum detection limit of 13 nM, (d) the immobilized system is able to simultaneously quantify nitrite and selenite at submicromolar concentrations in natural water samples with no further sample pre-treatment.

Nitrate and nitrite content in organically cultivated vegetables.

The nitrate and nitrite content of leaf vegetables (Swiss chard, sea beet, spinach and cabbage), "inflorescence" vegetables (cauliflower) and fruit vegetables (eggplant and vegetable marrow) grown with organic fertilizers have been determined by a modified cadmium­Griess method. Samples were purchased from organic food stores as well as collected directly from an organic farm in Madrid (Spain). Nitrate levels were much higher in the leaf vegetables (especially Swiss chard species; average over the different samples and species of 2778.6 ± 1474.7 mg kg(-1)) than in inflorescence or fruit products (mean values between 50.2 ± 52.6 and 183.9 ± 233.6 mg kg(-1)). Following Swiss chard species, spinach (1349.8 ± 1045.5 mg kg(-1)) showed the highest nitrate content, and nitrite was found above the limit of detection in some samples only (spinach, 4.6 ± 1.0 mg kg(-1); sea beet, 4.2 ± 0.7 mg kg(-1) and Swiss chard, 1.2 ± 0.4 mg kg(-1)). Some vegetables (spinach, cabbage and eggplant) had lower nitrate content in the samples harvested in summer, showing the influence of climatic conditions on the nitrate levels in a plant. The samples taken directly from the organic farm, with the exception of eggplant, had higher or slightly higher average nitrate values than samples purchased in the organic food stores, ranging from 117 to 1077%.

Immobilization and characterization of 2,3-diaminonaphthalene/cyclodextrin complexes in a sol-gel matrix: a new fluorimetric sensor for nitrite.

The aromatic diamino compound 2,3-diaminonaphthalene (DAN) has been extensively used to detect and quantify nitrite ions in biological and environmental samples. We have immobilized the DAN reagent in a porous silicate glass matrix, via previous incorporation of the dye in HP-beta-CD. Changes in fluorescence intensity were used to characterize the inclusion complexes and determine the association constant and stoichiometry of the process. Fluorescence spectrum of these complexes was also used to monitor their immobilization within the sol-gel matrix. Reactivity of the immobilized complexes was evaluated with increasing concentrations of nitrite up to 10 microM (with a detection limit around 20 nM). Results show that sol-gel immobilization does not modify the reactivity of the dye against nitrite and serves to prepare a highly sensitive ready to use fluorescence-based sensor for the specific measurement of nitrite at submicromolar concentrations with no further sample pretreatment.