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Publication
Featured researches published by Katja Žmitek.
Annals of Nutrition and Metabolism | 2008
Janko Žmitek; Andrej Šmidovnik; Maja Fir; Mirko Prosek; Katja Žmitek; Jaroslaw Walczak; Igor Pravst
Background: Coenzyme Q10 (CoQ10) is a naturally occurring compound that plays a fundamental role in cellular bioenergetics and is an effective antioxidant. Numerous health benefits of CoQ10 supplementation have been reported, resulting in growing demands for its use in fortifying food. Due to its insolubility in water, the enrichment of most food products is not easily achievable and its in vivo bioavailability is known to be poor. Water solubility was increased significantly with the use of an inclusion complex with β-cyclodextrin. This complex is widely used as Q10Vital® in the food industry, while its in vivo absorption in humans has not previously been studied. Methods: A randomized three-period crossover clinical trial was therefore performed in which a single dose of CoQ10 was administered orally to healthy human subjects. The pharmacokinetic parameters of two forms of the novel CoQ10 material were determined and compared to soft-gel capsules with CoQ10 in soybean oil that acted as a reference. Results: The mean increase of CoQ10 plasma concentrations after dosing with Q10Vital® forms was determined to be over the reference formulation and the area under the curve values, extrapolated to infinity (AUCinf), were also higher with the tested forms; statistically significant 120 and 79% increases over the reference were calculated for the Q10Vital® liquid and powder, respectively. Conclusions: The study revealed that the absorption and bioavailability of CoQ10 in the novel formulations are significantly increased, probably due to the enhanced water solubility.
Journal fur Verbraucherschutz und Lebensmittelsicherheit-Journal of Consumer | 2011
Igor Pravst; Katja Žmitek
In the European Union (EU), food supplements are regulated as food and their use is expanding rapidly. There is no enforcement to ensure that good manufacturing practices (GMPs) are followed during production but manufacturers are fully responsible for their products. Recently, the safety and quality of supplements available in the market has come into question. In our surveillance, we examined coenzyme Q10 content of 58 food supplements available in three EU member states or from Internet stores using high-performance liquid chromatography methodology. While some of the tested supplements contained almost exactly the same quantity of active ingredient as labelled, one-third of the products contained <70% of the labelled content. In the food supplements obtained online the medium content was lower than in the products purchased in pharmacies. To protect the consumer and assure the safety and quality of products, the market authorities need to exert better control. In addition, it would make sense to enforce additional requirements to ensure GMPs are followed in the manufacturing process of food supplements.
Nutrients | 2017
Igor Pravst; Živa Lavriša; Anita Kušar; Katja Žmitek
A voluntary gradual reduction in the salt content of processed foods was proposed Slovenia in 2010. Our objective was to determine the sodium content of prepacked foods in 2015 and to compare these results with data from 2011. Labelled sodium content and 12-month sales data were collected for prepacked foods (N = 5759) from major food stores in Slovenia. The average and sales-weighted sodium content, as well as the share in total sodium sales (STSS) were calculated for different food category levels, particularly focusing on processed meat and derivatives (STSS: 13.1%; 904 mg Na/100 g), bread (9.1%; 546 mg), cheese (5.1%; 524 mg), and ready-to-eat meals (2.2%; 510 mg). Reduced sale-weighted sodium content was observed in cheese (57%), a neutral trend was observed in processed meat and derivatives (99%) and bread (100%), and an increase in sodium content was found in ready meals (112%). Similar trends were observed for average sodium levels, but the difference was significant only in the case of ready meals. No statistically significant changes were observed for the matched products, although about one-third of the matched products had been reformulated by lowering the sodium level by more than 3.8%. Additional efforts are needed to ensure salt reduction in processed foods in Slovenia. Such efforts should combine closer collaboration with the food industry, additional consumer education, and setting specific sodium content targets (limits) for key food categories.
Nutrients | 2018
Nina Zupanič; Anita Kušar; Katja Žmitek; Nataša Fidler Mis; Igor Pravst
Scientific evidence of the association between free sugar consumption and several adverse health effects has led many public health institutions to take measures to limit the intake of added or free sugar. Monitoring the efficiency of such policies and the amount of free sugar consumed requires precise knowledge of free sugar content in different food products. To meet this need, our cross-sectional study aimed at assessing free sugar content for 10,674 pre-packaged food items available from major Slovenian food stores during data collection in 2015. Together, 52.6% of all analyzed products contained free sugar, which accounted for an average of 57.5% of the total sugar content. Food categories with the highest median free sugar content were: honey and syrups (78.0 g/100 g), jellies (62.9 g/100 g), chocolate and sweets (44.6 g/100 g), jam and spreads (35.9 g/100 g), and cereal bars (23.8 g/100 g). Using year-round sales data provided by the retailers, the data showed that chocolate, sweets, and soft drinks alone accounted for more than 50% of all free sugar sold on the Slovenian market. The results of this study can be used to prepare more targeted interventions and efficient dietary recommendations.
Nutrients | 2016
Katja Žmitek; Igor Pravst
Salt iodisation is considered a key public health measure for assuring adequate iodine intake in iodine-deficient countries. In Slovenia, the iodisation of all salt was made mandatory in 1953. A considerable regulatory change came in 2003 with the mandatory iodisation of rock and evaporated salt only. In addition, joining the European Union’s free single market in 2004 enabled the import of non-iodised salt. The objective of this study was to investigate the extent of salt iodising in the food supply. We examined both the availability and sale of (non-)iodised salt. Average sales-weighted iodine levels in salt were calculated using the results of a national monitoring of salt quality. Data on the availability and sales of salts were collected in major food retailers in 2014. Iodised salt represented 59.2% of the salt samples, and 95.9% of salt sales, with an average (sales-weighted) level of 24.2 mg KI/kg of salt. The average sales-weighted KI level in non-iodised salts was 3.5 mg KI/kg. We may conclude that the sales-weighted average iodine levels in iodised salt are in line with the regulatory requirements. However, the regulatory changes and the EU single market have considerably affected the availability of non-iodised salt. While sales of non-iodised salt are still low, non-iodised salt represented 33.7% of the salts in our sample. This indicates the existence of a niche market which could pose a risk of inadequate iodine intake in those who deliberately decide to consume non-iodised salt only. Policymakers need to provide efficient salt iodisation intervention to assure sufficient iodine supply in the future. The reported sales-weighting approach enables cost-efficient monitoring of the iodisation of salt in the food supply.
Nutrients | 2018
Nina Zupanič; Maša Hribar; Urška Pivk Kupirovič; Anita Kušar; Katja Žmitek; Igor Pravst
Consumption of industrially produced trans-fatty acids (TFAs) is a well-established health risk factor that correlates with the increased risk of developing cardiovascular disease. The recommended TFA intake is as low as possible, within the context of a nutritionally adequate diet. Different countries have introduced different measures to minimize the exposure of their population to TFAs. Previous data have shown that TFA content has significantly decreased in Western European countries, while this was not the case in many Central-Eastern European countries, including Slovenia. In the absence of regulatory requirements, a number of awareness campaigns were launched in Slovenia since 2015, with the common goal of lowering the use of partially hydrogenated oils (PHO), which are considered a major source of TFAs. To determine if this goal had been reached, we performed an assessment of the exposure of the population to prepacked foods containing PHOs in years 2015 and 2017. Altogether, data on the composition of 22,629 prepacked foods was collected from food labels, using a specifically developed smartphone application. Furthermore, the food categories with the most frequent use of PHOs were identified. The proportion of PHO-containing products was determined for each specific food category, and adjusted with the market share data. The results showed that in 2015, vegetable cream substitutes, soups, and biscuits were the categories with the highest penetration of declared PHO content. In 2017, the proportion of products with PHO decreased considerably. In vegetable cream substitutes the percentage of PHO containing items dropped from 30 down to 4%, in soups it decreased from 21 to 5%, in biscuits from 17 to 8%, and in crisps and snacks from 10 to 4%. However, PHO content remained notable among cakes, muffins, pastries, and biscuits. We can conclude that the voluntary guidelines and regular public communication of the risks related to the TFA consumption has had a considerable effect on the food supply, but did not result in sufficient removal of PHOs from foods.
Annals of Nutrition and Metabolism | 2008
Sabine Ellinger; Bianca M. Arendt; Rolf Fimmers; Peter Stehle; Ulrich Spengler; Roland Goerlich; I. Nourmohammadi; M. Modarress; K. Khanaki; M. Shaabani; Ezzedine Bouhlel; Monia Zaouali; Abdelhedi Miled; Zouhair Tabka; Xavier Bigard; Roy J. Shephard; D. A. de Luis; R. Aller; O. Izaola; M. Gonzalez Sagrado; R. Conde; Margaretha Haugen; Anne Lise Brantsæter; Jan Alexander; Helle Margrete Meltzer; Janko Žmitek; Andrej Šmidovnik; Maja Fir; Mirko Prosek; Katja Žmitek
115 New Aspects in Quality and Biofunctionality of Foods First Symposium of the Vienna Research Platform of Nutrition and Food Sciences (VRPNFS) April 25, 2008, Vienna, Austria Guest Editors: Elmadfa, I.; Wagner, K.-H. (Vienna) (available online only) 174 The Official FENS Calendar 175 FENS News 176 IUNS News
Biofactors | 2017
Katja Žmitek; Tina Pogačnik; Liljana Mervic; Janko Žmitek; Igor Pravst
Trends in Food Science and Technology | 2018
Igor Pravst; Anita Kušar; Katja Žmitek; Živa Lavriša; Liisa Lähteenmäki; Viktorija Kulikovskaja; Rn Malcolm; Charo Hodgkins; Monique Raats
Journal of Food Composition and Analysis | 2018
Helena Abramovič; Rajko Vidrih; Emil Zlatić; Doris Kokalj; Matthias Schreiner; Katja Žmitek; Anita Kušar; Igor Pravst