Effect of micro- and nanoplastics as food contaminants on the immune system
Currently, due to the increase in the distribution and accumulation of microplastics and nanoplastics (MP and NP) in the environment, their negative impact on human health has become a global problem.
The purpose of this research was to analyze the results of the studies on the effect of MPs and NPs on the body and evaluate their impact as pathogenetic factors of immune status disorders in vitro and in vivo.
Material and methods. The search for literary sources was carried out in the PubMed Internet resource, and the Scopus and Web of Science databases were also used. The Springer and Elsevier websites were used to access the full text of the articles.
Results. MP and NP enter the human body through ingestion of food, water, as well as through inhalation and contact with the skin. The results of the studies indicate that MP and NP particles, entering the human body, can move along with the blood and accumulate in various organs: the liver, spleen, heart, lungs, thymus, reproductive organs, kidneys and brain, i.e., to overcome the blood-brain barrier. The immune system is the main regulatory and protective system of the body, playing a major role in the recognition and destruction of foreign antigens of a viral, bacterial and chemical nature. Innate immunity is the first line of defense against pathogens. Macrophages, monocytes, natural killer cells (NK cells), and leukocytes (neutrophils) phagocytize antigens and present them to adaptive immune cells. It has been established that the damaging effect of MPs and NPs on immunity (immunotoxicity) is mainly due to the presence of oxidative stress with the formation of reactive oxygen species (ROS) and damage-associated molecular patterns (DAMP). The toxicity of MPs and NPs is realized by reducing the expression of the Nrf2 factor (a redox-sensitive transcription factor that regulates antioxidant protection) and the activation of p38 mitogen-activated protein kinases. In addition, it was found that the inflammatory process after exposure to MP and NPs is mediated by the expression of pro-inflammatory cytokines: IFN-γ, TNF-α, IL-1β, IL-6 and IL-33 and a decrease in the expression of cytokines: IL-4, IL-5, IL-10, IL-33 and TGF-β1, which leads to activation of the signal transducer and activator of transcription 3 (STAT3), nuclear factor kappa B (NF-κB) and cGas/STING pathways.
Conclusion. Analysis of the data of MP and NP effect on the immune system indicates the presence of aseptic chronic inflammation, which requires studying the causes and mechanisms of the development of inflammatory processes.
Contemporary approaches to the assessment of energy intake and energy expenditure in athletes
Assessment and interpreting of the energy expenditure (EE) in highly skilled athletes are important components of an effective training and performance prediction. Each component of EE (resting energy expenditure, thermic effect of food, and physical activity energy expenditure) is closely related to dietary patterns, the intensity and duration of physical activity, as well as a number of other factors that affect the functional state of athletes. Despite the importance of EE in the training process, coaches and athletes often do not take EE into account, which reduces the objectivity of assessing athletes’ functional state.
The purpose of this research was to summarize the recent information on the structure of EE and energy consumption in athletes.
Material and methods. The search and analysis of publications was carried out using the PubMed, MEDLINE, Scopus, Web of Science, eLIBRARY databases, mainly for the last 10 years, using the search keywords: rest energy expenditure, thermic effect of food, physical activity energy expenditure, energy intake, total energy expenditure, athletes.
Results. This overview includes information on the components of total energy expenditure, such as rest energy expenditure, thermic effect of food and physical activity energy expenditure, as well as generalized information on the factors affecting the variability of their values and methods for assessing one or another type of energy expenditure. International nutritional recommendations regarding the level of physical activity of athletes are systematized, as well as the advantages and disadvantages of methods for studying energy consumption and total energy expenditure are presented.
Conclusion. Combined study of energy intake and energy expenditure will help athletes avoid the negative impact of energy deficiency on performance, and the correct construction of the training process with the maintenance of adequate energy consumption will have a positive impact on the performance and recovery processes after intensive physical exertion.
Review of the possible impact of 100% juices on nutritional quality, risk of obesity and type 2 diabetes mellitus
Studies show that fruit juices are a source of macro- and micronutrients. Despite the fact that modern technologies for the industrial processing of fruits into juice are aimed at preserving the bioactive compounds of the original raw materials, juices are the subject of controversy due to the presence of free sugars and less dietary fiber than in fresh fruits.
The purpose of the work was to systematize the available studies on the effect of 100% juices on nutrition quality, obesity and type 2 diabetes mellitus.
Material and methods. Systematic search in PubMed, Google Scholar, eLIBRARY databases in accordance with the inclusion criteria: the study examined 100% fruit or vegetable juices, the article was in Russian or English in a peer-reviewed journal, the subjects (in the case of clinical studies) were people aged 1 to 18 years and older. 98 sources were analyzed based on the title of the article, of which 35 did not relate to juices. 63 sources were analyzed based on their abstracts, of which 28 were included in the main study.
Results. According to the results of the literature analysis, it follows that moderate consumption of 100% juices not only does not have negative effects on human health, but, on the contrary improve the health of the organism. In particular, its intake helps lower blood pressure and the content of highly sensitive C-reactive protein, thereby reducing the risk of cardiovascular diseases. Juices enrich the daily diet due to the macro- and micronutrients they contain, which improves the quality of nutrition in general. Researches prove that there is no correlation between moderate juice consumption and type 2 diabetes onset. The glycemic index of the juices is low or medium, which distinguishes them from standard soft drinks containing sugar. The consumption of juices (100–500 ml/day) does not increase the risk of obesity in adults and children.
Conclusion. Negative effects, such as weight gain and an increased risk of diabetic diseases, can only be observed with excessive consumption of juices.
Comparative characteristics of the amino acid composition of protein from traditional sources and entomoprotein: calculated data
The growth of the world population leads to an increase in demand for food consumption. Along with the projected reduction in demand for meat products, a search is underway for a new type of food (“novel food”), one of the promising options for which are insects. In 2023 the European Commission has registered flour made from house cricket (Acheta domesticus) as a “novel food” for human consumption. Currently, the amino acid composition of both new types of food and the diet that includes them is not regulated. Accordingly, the potential amino acid imbalance in the diet when entomoprotein is included need to be further investigated.
The aim of the study was to characterize the amino acid composition of a simulated diet using protein obtained from house cricket.
Material and methods. To assess the balance of diets in terms of amino acid composition, a comparative analysis was made of the actual diet containing protein from traditional foods (scenario 1) and the diet with the likely replacement of beef, pork and poultry with a product containing A. domesticus protein (entomoprotein) (scenario 2). The volume of food consumption has been calculated based on the results of the assessment of a sample survey of household budgets. The study included foods with an established value of annual consumption, that was calculated as daily consumption. The content of essential amino acids in food sources of protein, as well as in the domestic cricket protein, was evaluated using the data from relevant sources. Dietary balance was assessed by calculating its digestibility using data on amino acid scoring, the utility of essential amino acids, the excess content of individual essential amino acids, and the comparable excess content of essential amino acids.
Results. We determined the daily consumption volumes of basic foods, formed consumption scenarios, including with the potential use of a protein product based on entomoprotein. Comparative analysis of the amino acid composition of the diet showed significantly higher content (from 1.4 up to 2.9 times) of amino acids in the diet in scenario 2. The results of calculating the amino acid score and utility coefficient showed that a diet using entomoprotein could provide a better usage of amino acids for protein synthesis compared to the «traditional» diet, however, the digestibility of protein from the traditional diet is higher compared to entomoprotein (96.8 vs 89.1%).
Conclusion. Despite the fact that the utility of essential amino acids in the scenario of replacing meat products with a product containing A. domesticus entomoprotein is higher, while the digestibility of protein is lower, the differences identified are insignificant.
Application of digital transformations of dietary microdata and factor analysis to study the nutritional patterns of breakfast and its significance in providing the nutritional value of the diet of adults
Eating disorders with skipping meals are considered as a risk factor for chronic non-communicable diseases. Frequent skipping of meals is associated with the risk of developing metabolic syndrome, type 2 diabetes, and obesity. Breakfast is considered to be the most important meal of the day. However, studies on the impact of skipping breakfast on the risk of overweight and obesity are highly controversial.
The aim of this study was to analyze the prevalence of skipping the morning breakfast meal and its impact on the actual daily intake of nutrients and energy in the Russian adult population.
Material and methods. The data from a sample survey of dietary intake conducted in 2013 by the Russian Federal State Statistics Service have been used. The analysis included adult respondents (19 years and older) in the amount of 163 000 people in 2 stages of the survey (in April and September). The dietary intake of all members of the surveyed households was studied using the 24-hour recall method. Since the survey questionnaires did not contain information about type of meals, therefore, with the help of binning in thзe SPSS program, time intervals of the maximum food energy intake by the respondents were established, which were taken as evidence of the main meals and snacks.
Results. Of the main meals, the largest proportion of respondents skipped dinner (23.1%), then breakfast (13.0%), and the smallest proportion skipped lunch (5.7%).The proportion of men and women who skipped breakfast was 12.6 and 13.3%, respectively, a greater frequency of skipping breakfast was observed at a young age (19–30 years, 19.3%) and at an old age (75 years and older, 16.1%). With an increase in the average monthly income of a family, the percentage of those who skip breakfast increases. Adult members of families with many children (3 or more children), whose average per capita income is lower than those in families with 2 children, skip breakfast less frequently. The smallest share of people skipping breakfast was found in the North Caucasian and Southern districts, and the maximum in the Siberian and Far Eastern districts. Adults who skipped breakfast had a higher percentage of malnourished (BMI <18.5 kg/m2) and normal nutritional status (BMI 18.5–24.9 kg/m2). At the same time, the proportion of people who consumed breakfast was significantly higher in overweight people (25.0–29.9 kg/m2), and no differences were found among obese people. It is shown that skipping breakfast is accompanied by a decrease in the energy value of the daily diet by an average of 200 kcal. Despite the increase in the caloric content of the 2nd breakfast, afternoon snack and evening snack in absolute terms (р<0.01), there was no compensation for the loss of energy value in the absence of breakfast. A decrease in the absolute values of nutrient intake associated with a decrease in energy consumption was established. However, skipping breakfast showed a decrease in added sugar intake as a per cent of total calorie intake (12.1±8.6 vs 13.2±9.1%, р<0.01), while the contribution of other macronutrients to energy intake did not change significantly. In connection with the heterogeneity of the actual dietary intake of the population, factor analysis was used to describe the main food models of the breakfast using the principal component method. 6 factors were identified that determine the eating patterns of breakfasts and correlate with 2–4 individual food items of actual dietary intake.
Conclusion. The results obtained are consistent in a number of positions with the literature data, in particular, indicating a decrease in daily energy consumption when skipping breakfast.
Spectrum of food diversity of megapolis’ inhabitants obtained by the analysis of buying activity
The food diversity is a significant indicator of a healthy diet.
The aim of the study was to assess the indicators of food diversity in the metropolis (Moscow) based on the analysis of consumer activity in a large retail chain.
Material and methods. 201 904 holders of loyalty cards of the retail network were selected from the depersonalized purchase data for 2016–2018 according to the following selection criteria: the presence of a dense segment of purchases (more than 4 weeks, where there was at least 1 purchase in 2 weeks), where the total cost of purchases was at least 4700 rubles and at least 4 different products were purchased. From of these, 111 136 buyers have data available by gender, 43 046 by age. The classification of a set of purchased products and dishes by food groups was carried out, and complex dishes were transformed into a set of their ingredients and the distribution of the unique values of the corresponding food groups was carried out. Counting the number of unique preferences (count base diversity) by the number of positions in each of the 6 food groups (cereals, fish and meat, fat products, dairy products, vegetables, fruits and berries) allowed us to estimate the amount of food diversity. The total number of food categories in all subgroups was also calculated.
Results. The low value of food diversity in the category of cereals and cereals was found in 2/3 of buyers, in the category of vegetables and fruits in 60% of buyers, in the category of meat and fish products in half of buyers, in the category of fat-and-oil products in 63.7% and in 44.2% of buyers of dairy products. An acceptable total number of categories of purchased products (more than 20 per week) was achieved only in 14.5% of men and 16.7% of women from our sample. In general, lower indicators of dietary diversity are typical for men and young people (up to 45 years old).
Conclusion. Thus, it can be concluded that the importance of food diversity as a factor of health protection is underestimated by the population, especially by young people, which can lead to an increase in the burden on healthcare due to the earlier debut of a wide range of chronic diseases.
Rats’ liver morphological features under conditions of different supply with vitamins and minerals
The current practice of novel food safety assessment in the Russian Federation involves toxicological studies on the alimentary model of adaptation potential reduction of laboratory animals. Since vitamin and mineral deficiency can affect the size of structural elements of tissues, an objective estimation of the results obtained using this model is possible when determining the range of fluctuations of the studied morphometric parameters under conditions of different essential substances’ supply, as well as under conditions of simulated toxic effects on the background of the corresponding supply.
The purpose of the research was to investigate the morphological and morphometric features of the liver under the influence of reduced intake of vitamins and mineral elements in the combination with toxic effects of various nature, during growth and puberty of male Wistar rats.
Material and methods. The article analyzed data of 4 model experiments on 140 animals that received semi-synthetic casein diet with different supply of vitamins B1, B2, B3, B6 and mineral elements Fe3+ and Mg2+, as well as data of 2 experiments on 180 animals with simulated toxic load of cadmium (Cd2+) salts and carbon tetrachloride. The animals were ~95 days old at the time of sampling, the duration of the experiments was ~65 days. For the analysis we used data on rats’ body weight on the day of material sampling, absolute and relative liver weight, hepatocyte diameter, nucleus diameter and hepatocyte cytoplasm size in the central and peripheral zones of hepatic lobules. A total of 200 cells were analyzed in each group of animals. In accordance with the study design, all quantitative traits of the groups that received diets with an essential nutrient supply ranging from 75 to 2% were compared with the group that received a complete diet (100%).
Results. Morphometric examination of hepatocytes revealed a linear decrease in the size of cell structural elements in the series of reducing the content of essential micronutrients in the diet. Under the conditions of 2–4% vitamin and mineral supply, cell and nucleus diameters as well as cytoplasm size were by ~16.8, 12.6 and 21.1% (p<0.05) lower respectively than in rats with optimal supply of these substances; under the conditions of 9–19% supply were by ~9.2, 9.7 and 8.7% lower (p<0.05); higher levels of supply caused reduction of hepatocyte, nucleus and cytoplasm sizes in a range not exceeding 5% (p>0.05). When comparing the size of hepatocytes of rats subjected to toxic load with the hepatocytes of rats referred to the reference standard, an increase in the size of hepatocytes under the action of carbon tetrachloride by 17.4% (p<0.05) on average and under the action of cadmium salts by 4.6% (p<0.05) was noted.
Conclusion. Based on the analysis of liver morphological and morphometric studies’ data, there were established sizes of hepatocytes structural elements in the rats kept on diets with decreasing supply with B group vitamins, iron and magnesium salts; the linear decrease in the sizes of structural elements of hepatocytes in the series of reduction of B group vitamins, iron and magnesium intake was revealed. Toxic exposures to carbon tetrachloride and cadmium salts against the background of a 19–30–75% supply with essential substances led to an increase in the hepatocytes size, the correlation between the degree of toxicant exposure and the supply level is not significant.
Development and validation of the questionnaire for testing the level of knowledge of athletes on nutrition
A large number of socio-economic factors affect the nutritional status of an athlete. Athletes’ nutritional awareness can affect long-term health and occupational disease risks among athletes. To assess the level of knowledge of athletes about nutrition, scientists of the world community have developed various types of tools in the form of questionnaires that are successfully used in practice to analyze the nutrition of athletes and optimize it. However, existing questionnaires and forms for filling them out have certain disadvantages, the most significant of which is a large number of questions, which requires significant time expenditure for athletes.
The goal of the research was to develop a questionnaire for conducting a survey of athletes using the classical theory of testing and the principles of The nutrition for sport knowledge questionnaire (NSKQ). Based on the results of the survey, an assessment was made of the hypothesis about the influence of the basic knowledge of athletes in matters of nutrition on the correctness of their answers within the questionnaire. The developed survey tool was also validated to ensure its reliability.
Material and methods. To obtain general information about the target audience and identify the level of knowledge of athletes about nutrition, a questionnaire was developed, which subsequently went through several stages of verification and validation. The respondents were athletes from the “Kronverkskie Barsy” student sports club at ITMO University. At the first stage of developing the questionnaire, questions were prepared about the target audience (TA) and blocks of questions about the basic knowledge of the TA on the main macronutrients of food, in particular on the blocks “proteins” (P), “fats” (F) and “carbohydrates” (C). At the second stage of the work, an online format for surveying respondents in a Google Form was implemented with a maximum time for completing the survey no more than 15 minutes. At the third stage of the study, the results of the survey were evaluated with preliminary data coding based on the Jamovi program. As a result, the analysis of the proposed hypotheses and the evaluation of the obtained research data were carried out.
Results. This study involved 56 athletes, of which 59% were women and 41% were men, average age 20.8±4.9 years. Most of the survey participants were ITMO University students (87.5%). 60.7% were involved in sports at a professional level, 35.7% – at an amateur level, and 3.6% of respondents belonged to elite sports. The average body mass index of the respondents (20.6±4.8 kg/m2) corresponded to the norm according to the Regulations of the World Health Organization. During the survey, the majority of respondents (78.6%) reported that they had basic knowledge on nutrition, a smaller part of the respondents – 12 (21.42%) people did not have basic knowledge about nutrition. It was suggested that there were significant differences in the correct answers of respondents with basic knowledge on nutrition (group 1) and respondents who didn’t have this knowledge (group 2). An assessment of the total number of correct answers in the total blocks (“proteins”, “fats”, “carbohydrates”) didn’t confirm the presence of significant differences in the knowledge of respondents in group 1 (81.0±5.5%) and group 2 (73.0±7.9%). However, it should be noted that there were significant differences in the number of correct answers in the «carbohydrates» block in group 1 (76.5±5.5%) and group 2 (61.1±3.7%). The validity of the developed survey model was tested using the Jamovi program with the determination of the Cronbach reliability factor (>0.7), corresponding to sufficient internal consistency of questions.
Conclusion. The questionnaire developed using the classical theory of respondent testing was evaluated for validity and reliability using the Jamovi software. This study was conducted with the participation of a sufficient number of respondents in the amount of 56 athletes. The hypothesis put forward about the influence of basic knowledge of athletes in nutrition on the correctness of their answers to questions about the main macronutrients of food was confirmed only for the “carbohydrates” block. This area of knowledge is set as the most difficult for respondents to answer. It should be noted that in the total assessment for all blocks of macronutrients (“proteins”, “fats” and “carbohydrates”) no significant differences were found in nutrition knowledge of the two groups of athletes.
Methods for the identification and quantification of microplastics in foods (a review)
The adverse effects of microplastics (MP) found in food on the health have recently been recognized as a new source of human health risks. In order to evaluate and minimize them, it is necessary to evaluate the exposure using sensitive and specific methods.
The aim of the research was the substantiation of methodological approaches to the identification and quantification of microplastics in food based on the analysis of literature data.
Material and methods. Literature selection was carried out using the PubMed international reference database for the period from 2014 to 2023 using keywords corresponding to the context of the research theme. A total of 159 sources were selected, of which 94 original and review papers were included in the review according to the criteria of their relevance to the problem under consideration, scientific reliability and completeness.
Results. At present, various approaches have been developed that make it possible to isolate MPs from complex bioorganic matrices (such as, for example, seafood), classify them by chemical composition, and quantify their content through the mass or number of particles. Among the most developed physic-chemical methods for the analysis of MPs are Fourier transform IR spectrometry and Raman microspectrometry, pyrolysis gas chromatography – mass spectrometry, thermogravimetric analysis, as well as approaches based on liquid chromatography, microfluorimetry, analytical scanning and transmission electron microscopy and others. Unsolved problems in the field of MP research in food include the high laboriousness and low performance of the identification technologies used, the lack of reference and standard samples of MP, the complexity of the equipment used, which makes it difficult to use it for routine hygienic control. The issue of the influence of MP aging degree on the results of its qualitative and quantitative determination has not been sufficiently studied. Some hopes in the field of development of rapid analysis of MTs are pinned on the use of aptamers.
Conclusion. Existing analytical methods make it possible to determine the content of MPs in environmental objects, but further improvement and validation of these methods is required in relation to the assessment of the content of MPs in various types of food.
Comparative characteristics of oxidative modification intensity of proteins in infant milk formulas
Cow’s milk is mainly used in the production of infant milk formulas. However, the protein composition of cow’s milk differs significantly from the proteome of breast milk. In addition, various technological factors significantly affect the properties and structure of proteins, susceptibility to oxidative processes. This article uses a method of complex evaluation of the products of oxidative modification of proteins to characterize the total level of carbonyl compounds with the analysis of the ratio of aldehyde-dinitrophenylhydrazones (ADNPH) and ketone-dinitrophenylhydrazones (CDNPH), which increases the possibility of determining the severity of protein damage.
The purpose of the study was to compare the level of indicators of oxidative modification of proteins in adapted milk infant formulas.
Material and methods. The research objects were 4 dry adapted milk infant formulas, as well as ultra-pasteurized cow’s milk. The intensity of oxidative modification of milk proteins was determined spectrophotometrically by the reaction of carbonyl compounds with dinitrophenylhydrazine (DNFG).
Results. With spontaneous oxidation in infant formula, the total area of carbonyl derivatives of proteins (Sомб) was increased compared to the indicators of ultra-pasteurized cow’s milk. The greatest change occurred in relation to ADNFG indicators (SАДНФГ), the level of which increased in 3 formulas by 48.6–59.4%. The content of ketone derivatives (SКДНФГ) did not differ significantly in the studied mixtures from milk indicators. The level of carbonyl derivatives of proteins in milk infant formulas was even more elevated during the induction of oxidation by the addition of iron ions and hydrogen peroxide to the incubation medium. The content of both total and various fractions of carbonyl compounds exceeded the corresponding indicators of cow’s milk by 2.0–2.6 times.
Conclusion. The results of the study indicate a greater susceptibility to oxidative damage of proteins in milk infant formulas, compared with cow’s milk.
Modified method for obtaining phycocyanine concentrate of Arthrospira platensis biomass
The biomass of Arthrospira platensis cyanobacteria is a source of bioactive compounds such as chlorophylls, carotenoids, and, particularly, phycobiliproteins: C-phycocyanin and allophycocyanin. The wide range of biological activity shown by extracts with a high content of phycocyanins determines the prospects for their use as dietary supplements and ingredients of special foods. For food purposes, the degree of purity of phycocyanin concentrates, determined by the ratio of optical densities of their aqueous solutions at two wavelengths, namely D620/D280, must be greater than 0.7. Most methods for obtaining phycocyanin concentrates include laborious steps of fractional ammonium sulphate precipitation of protein from A. platensis biomass extracts followed by removal of salts solution. The use of membrane technology, specifically microfiltration, makes it possible to significantly intensify and simplify the process of obtaining phycocyanin concentrates.
The aim of this research was to modify the method for obtaining a high-purity A. platensis phycocyanin concentrate by replacing the stage of ammonium sulfate precipitation of the protein by ultrafiltration of the extract followed by microfiltration.
Material and methods. A sample of dry A. platensis biomass was used as a feedstock. Extraction of A. platensis biomass was carried out at a temperature of +40 °C for 3 h, the resulting suspension was centrifuged, and the supernatant was separated from the sediment. The obtained extract was subjected to ultrafiltration (membrane with a pore diameter of 30 kDa) followed by removal of the permeate containing low molecular weight impurities. The retentate was subjected to microfiltration (membrane with a pore size of 0.2 μm), concentrated by reverse osmosis and freeze-dried.
Results. The content of C-phycocyanin and allophycocyanin in the dry concentrate was 42.0±1.3 and 7.0±0.3%, respectively, the degree of purity was 1.98.
Conclusion. The scheme for obtaining A. platensis phycocyanin concentrate has been modified. A concentrate was obtained with a high degree of purity, allowing its use in food.