6 . 2021

Risks associated with the consumption of inorganic and organic arsenic


It is known that the chronic intake of arsenic (As) leads to the development of multisystem pathologies. In the case of high levels of As consumption, the risks of negative effects of exposure to inorganic and methylated forms persist for decades. The International Agency for Research on Cancer (IARC) has established that all inorganic forms of As are absolute carcinogens (group 1). Methylated forms of As are classified as substances possibly carcinogenic to humans (group 2b). Not metabolized in the human body forms of organic As are not carcinogenic to humans (group 3).

The aim - assessment of health risks of various forms of As contained in food, including seafood.

Material and methods. The scientific data regarding the risks associated with As contamination of food obtained by using PubMed, Web of Science, Google Scholar databases, legislative and regulatory acts of the Eurasian Economic Union, the Russian Federation, the Codex Alimentarius Commission, the European Union and other countries have been analyzed.

Results. The analysis of the available data showed that the degree of As toxicity decreased in the following order: glutathione of dimethylarsonic acid (DMAIIIGl) > methylarsic acid (MMAIII) > dimethylarsic acid (DMAIII) > arsenic hydrocarbons (AsHC) > arsenite (AsIII) > arsenate (AsV) > trimethylarsine (TMAIII) > methylarsonic acid (MMAV) > dimethylarsonic acid (DMAV) > DMAIII-sugar glyceride > DMAV-sugar glyceride > thio compounds of DMAV > arsenosugarsIII > arsenosugarsV > tetramethylarsonium chloride (TETPA) > trimethylarsine oxide (TMAO), arsenocholine (AsC) > arsenobetaine (AB). Consequently, the toxicity of some methylated and organic forms of As (for example, DMAIIIGl, AsHC) may be higher than that of its inorganic forms. It is known that As is found in foods mainly in organic forms. When ingested with food, As organic forms are metabolized and, thus, could cause a number of negative effects in the organism. Conclusion. High levels of organic and inorganic forms of As in food, including seafood, could have a negative impact on the health of the population, which makes it necessary to conduct additional assessments of the health risks of various forms of As entering the body. The insufficient amount of data on the toxicity of organic forms of As indicates the impossibility of separate setting of safety maximum levels for organic and inorganic forms of As in foods.

COVID-19-associated diarrhea


In addition to the typical clinical picture of respiratory symptoms and intoxication, the SARS-CoV-2 virus is also characterized by a gastroenterotropic effect. Diarrhea is one of the most common gastroenterological symptoms of COVID -19 and is detected, according to the various authors, in 2-49.5% of cases, including children. The presence of diarrhea aggravates the patient’s clinical condition, limits the possibility of carrying out the necessary diagnostic manipulations, and complicates the selection of therapy. The article provides an overview of the scientific literature on the formation of diarrheal syndrome in patients with COVID-19.

Objective. Analysis of scientific publications studying the pathogenesis, incidence, clinical features, aspects of diagnosis and therapy of diarrhea in patients with COVID-19.

Material and methods. A search was made for scientific publications on the electronic resources PubMed, Google Scholar and

Results. The pathogenesis of diarrhea in a new coronavirus infection is complex and includes, among other things, the effect of the virus on the angiotensin-converting enzyme 2 receptors, inducing an inflammatory process in the gastrointestinal tract mucosa, neurotropic effect on the autonomic regulation of intestinal motor activity, disturbance of the colon microbiota, liver and pancreas damage. Another important pathogenetic aspect of diarrhea in COVID-19 is iatrogenic one, i.e. a side effect of drugs used in the treatment of a new coronavirus infection and its complications, and the activation of opportunistic clostridial intestinal flora against the background of antibiotic therapy. The variety of pathogenetic mechanisms of diarrheal syndrome formation allows us to speak of “COVID-associated diarrhea” as an independent clinical phenomenon characteristic for the new coronavirus infection. Mandatory diagnostic algorithm of a patient with COVID-19 and diarrhea is the fecal analysis test for toxins Cl. difficile, while the possibility of endoscopic examinations during the pandemic is limited. Compliance with the hygiene measures, diet correction and nutritional support, rational antibiotic therapy of COVID-19 complications, careful use of antiperistaltic antidiarrheal drugs, nonspecific therapy (antiviral, rehydration, adsorbents) are considered as the main therapeutic approaches for diarrheal syndrome against the background of COVID-19. The administration of probiotics and antibacterials should be considered in case of confirmed clostridial co-infection.

Conclusion. Diarrhea is a frequent clinical manifestation of COVID-19 and can affect the course of the disease. The complex genesis of diarrheal syndrome requires further study of therapeutic strategies and nutritional support for patients after COVID-19.

The role of the gut microbiome in health and diet-related diseases


In recent years, new data have been obtained on the participation of the organism-associated microbiota in the pathogenesis of many non-communicable diseases. However, these data are mostly multidirectional and require interpretation.

The aim - to highlight the role of the intestinal microbiome in the human body in health and some nutritional-dependent pathologies, taking into account modern scientific knowledge.

Material and methods. The analysis of domestic and foreign scientific literature in the field of studying the intestinal microbiome in humans and practical measures for its correction in the most common diet-related non-communicable diseases, using the Scopus, Web of Science, PubMed, Google Schoolar, eLibrary, Cyberleninka databases has been held. Results. The data on the significance and function of the intestinal microbiome for the human body in health and in nutrient-dependent diseases, with attention to publications containing information that meets the criteria of scientific evidence have been summarized. It has been shown that the intestinal microbiome plays a biologically significant role not only in digestion processes, but also in many metabolic processes and in the adaptive potential of the human organism. The role of the microbiome in the metabolism of lipids supplied with food, as well as its participation in the mechanisms of development of dys-lipidemias and metabolic syndrome in the case of dysbiotic disorders in the intestine, have been described.

Conclusion. Nowadays the importance of the intestinal microbiome as an integral factor in the vital functions of the organism that determines the development and maintenance of the immune system, digestive processes, and biochemical balance in humans in norm has been convincingly proven at all levels of numerous studies. However, the study of the effect of dysbiotic changes in the gut microbiota as a direct cause of the development of non-communicable diseases requires further research with a high level of evidence.

Nutrition status and obesity paradox in chronic obstructive pulmonary disease


Chronic obstructive pulmonary disease (COPD) is one of the main causes of increasing morbidity and mortality worldwide, and therefore is becoming a major public health problem.

The aim of this research was to summarize the data of observational and clinical studies concerning the influence of nutritional status (both malnutrition and obesity) on the COPD course and outcomes.

Material and methods. The databases PubMed, RSCI, MEDLINE, EMBASE were used for the period from January 2008 to February 2021, with a total of 582 works viewed. Searches included the keywords: nutritional status, obesity paradox, chronic obstructive pulmonary disease.

Results. In the pathogenesis of malnutrition in COPD, such phenomena as excessively enhanced metabolism, loss of appetite and dietary imbalance are most often described. It is proposed to pay great attention to preventing muscle loss in the correction of these phenomena. More than a third of COPD patients has obesity, which is associated according to some reports with a low quality of life, an increased frequency of hospitalizations for exacerbations, but also with better survival. The issue of the obesity paradox in COPD is increasingly discussed in scientific literature. Many authors emphasize that basic scientific research will help to understand the mechanisms of obesity and COPD relationship, as well as timely adjust the rehabilitation program, improving the quality of patients’ life.

Conclusion. Nutritional status is the important factor in COPD outcomes. Maintaining muscle mass is a priority in COPD patients, including those with obesity. The proposed dietary therapy should take into account the food intake according to the needs of patients, the correct proportion of macronutrients and the level of the body mass index.
Physiology and biochemistry nutrition

Effect of per os administration of dihydroquercetin aqueous form on energy exchange in blood lymphocytes of rats with experimental cardiomyopathy


Cardiomyopathies are among the most severe myocardial pathologies, which are characterized by resistance to therapy and high mortality due to increasing heart failure and arrhythmia. Cardiomyocyte pathological changes upon cardiomyopathies are associated with mitochondrial dysfunction, leading to excessive formation of reactive oxygen species and the development of oxidative stress. In this regard, the study of the therapeutic potential of antioxidants in cardiomyopathies, as well as the mechanisms of their action on the functioning of mitochondria, is relevant and of high practical importance.

The aim of this study was to determine the effect of oral 14-day administration of dihydroquercetin in a water-soluble form (DHQ-WF) on the activity of the key marker of mitochondrial respiration [succinate dehydrogenase (SDH)] and the cytoplasmic marker of glycolysis [lactate dehydrogenase (LDH)] in blood lymphocytes, as well as on the serum level of lipid peroxidation (LPO) in control rats and rats with experimental cardiomyopathy.

Material and methods. Adult male Wistar rats (body weight 220-240 g) were used for the study. Isoprenaline hydrochloride was used to induce cardiomyopathy (IIC) in animals (twice subcutaneous injection at a dose of 150 mg/kg body weight, with a break of 24 hours). DHQ-WF was added to the drinking water for 14 days at the dose of 15 or 30 mg/kg body weight. SDH and LDH activity in lymphocytes was measured using a highly sensitive cytobiochemical method on a blood smear according to the reduction of nitrotetrazolium blue chloride to diformazan of dark blue color. The content of malone dialdehyde (MDA) in the blood serum, heart and liver mitochondria was determined spectrophotometrically using thiobarbituric acid. Mitochondria were isolated from rat tissues by the conventional method of differential centrifugation. Mitochondrial respiration was recorded using a polarographic method.

Results. Experimental cardiomyopathy in rats was accompanied by a twofold increase in blood serum MDA level, as well as by a significant increase in SDH and LDH activity in blood lymphocytes. The oral administration of DHQ-WF in cardiomyopathy at a dose of 15 mg/kg body weight led to a significant decrease in serum MDA level, but did not reduce the activity of SDH and LDH in blood lymphocytes, compared with animals with cardiomyopathy that did not receive DHQ-WF. In the control group of animals, the use of DHQ-WF at a dose of 15 mg/kg body weight significantly increased blood lymphocyte LDH activity, but did not have a statistically significant effect on SDH activity and the parameters of mitochondrial respiration and oxidative phosphorylation, the level of MDA in heart and liver mitochondria. Increasing the dose of DHQ-WF administered to 30 mg/kg had less effect on changes in these parameters in control animals.

Conclusion. The data obtained indicate that in experimental cardiomyopathy in rats, the course application of DHQ-WF at a dose of 15 mg/kg of body weight acts as an effective antioxidant that prevents the development of lipid peroxidation in blood serum, and can modulate energy metabolism towards the enhancement of glycolysis in blood lymphocytes in control animals.

Hygiene of nutrition

Nutrition and body composition in young women with various leptin and ghrelin levels


Body mass and its composition depend on the energy equilibrium due to the consumption of energy-intensive macronutrients and energy expenditure under strict neuroendocrine control. Leptin andghrelin are the most important regulators of the energy balance; they modulate the redistribution of substrate flows in metabolic pathways.

The aim of the research was the assessment of nutrient intake in conjunction with the analysis of body composition and primarily hormonal regulators of energy balance in young women with various body mass index (BMI) values.

Material and methods. 88 girls aged 18-22 were examined. Based on the definition of BMI, three groups were formed: group 1 -young women with BMI <18.5 kg/m2, underweight (UW); group 2 - BMI of 18.5 to <24.9 kg/m2, normal weight (NW); and group 3 - BMI of >24.9 kg/m2, overweight (OW). Body composition was determined using bioelectrical impedance analysis. Nutrition was assessed using the 24-hour food recall. Enzyme-linked immunosorbent assay was used to measure leptin and ghrelin concentrations.

Results. The study of nutrition in young women with various energy balances revealed intergroup differences in macronutrient and calorie intake. Underweight students demonstrated insufficient consumption of energy (1267±114 kcal/day) from all macronutrients. Overweight and obese young women ate a lot and consumed higher than daily average amounts of proteins (95.7±8.5 g) and fats (129.5±12.2 g). Young women with normal body weight consumed excess energy from fats - 33.7±1.1% (the same as in overweight subjects - 39.3±2.4%), but the relative carbohydrate and protein intake was below recommended level. An excess of energy consumed with food reflected in the degree of adipose tissue development and the energy balance of the examined persons. Leptin concentration increased at higher BMI values and depended on adipose tissue level, amounting to 5.0 [4.2; 5.7], 14.2 [9.7; 14.7] and 20.3 [14.8; 21.3] pg/ml (p<0.009). Ghrelin level was 13.0-14.2% higher in overweight subjects (2.09 [2.00; 2.27] ng/ml) vs. other groups (p<0.003).

Conclusion. Students with various BMI values demonstrated various dependences between macronutrient consumption and body composition. The results show that fat intake play a more important role in adipose tissue formation in young women than diet carbohydrates. Overweight and obese subjects have additional regulation factors associated with a stressed regulatory system.

Nutritional status of preschool children of Moscow megalopolis at the beginning of the 21st century (somatometric aspects)


Obesity is one of the most important and actual problems of public health, of healthcare, which dramatically expanded through the latest four decades.

The aim of the study was the analysis of physical conditions of Moscow preschoolers at the beginning of 21th century as the indicator of nutritional status in «obesogenic» environment of megalopolis.

Material and methods. Complex anthropometric study of children attending kinder gardens in Moscow (aged 3-7 years) was held in 2005-2006 (n=759). Literature data on samples of the 1970s were used for comparison. Anthropometric measurements were used to calculate personal values of body mass index (BMI, kg/m2). The more detailed estimation of somatic specificity of children included calculation of average values of standardized differences of each single body dimension of material of 2005-2006 from the values of samples of the 1970s.

Results and discussion. The distribution of BMI of Moscow preschoolers at the beginning of 21th century (13.6% were overweight and 7.5% were obese) is quite comparable to the results of other population studies in Russia and around the world. The circumferences, mediated by adipose tissue, and skinfolds of modern Moscow preschoolers showed very significant increase of average standardized levels of dimensions (0.9-1.1 standard deviations as compared to the data of the 1970s). The comparison with the results of the similar study of Moscow school children allows, probably, to speak about the existence of accumulation effect as the mechanism of obesity development in the age aspect.

Conclusion. The effect of the significant and valid increase of adiposity in preschoolers, combined with very modest changes of the size and shape of skeletal/muscle system and even its relative weakening was shown based on the results of the survey of Moscow preschoolers, conducted in 2005-2006, in comparison with the series of the 1970s.

Nutrition and nutritional status of underweight patients


Insufficient body weight is one of the manifestations of nutritional disorders. Diseases associated with malnutrition occur in 10-12% of the population.

The aim of the work was to study indicators of nutritional status and actual nutrient intake in patients with insufficient body weight.

Material and methods. The study included 48 women aged 31.4±11.8 years, with a body mass index below 18.5 kg/m2. The body composition was estimated by bioelectrical impedance analysis. Nutrient intake was assessed using food frequency questionnaire, physical activity was evaluated by the survey method, using the computer program “Evaluation of nutrition”, also blood biochemical parameters were determined.

Results. Body fat mass was below average values in 93.8% of patients, while only 50.0% of women had a skeletal muscle deficiency, and 10.4% surveyed had skeletal muscle mass above average values. The energy value of the daily diet was 1982 ±282 kcal, and daily energy expenditure was 2158±255 kcal. In the structure of the diet, fats prevailed (42.0±10.5% of daily calorie intake) and there was a significant lack of total carbohydrates (39.9±10.4% of daily calorie intake) and dietary fiber. Fat intake was exceeded in 92.9% of patients. Insufficient carbohydrate intake was also observed in 92.9% of patients. In most patients, daily intake of potassium, calcium, magnesium, iron, B vitamins did not reach the recommended level, while sodium and phosphorus intake was excessive. The nutrient intake imbalance affected blood biochemical parameters in hypercholesterolemia (in 41.7% of patients) and hypertriglyceridemia (31.3%), and decreased calcium (30.0%), iron (12.8%) and vitamin D (52.2%) levels.

Conclusion. Thus, for underweight patients, correction of the diet and dispensary observation is required to determine body composition and biochemical parameters, in particular, the fat and muscle components of the body weight, lipid metabolism indicators, the supply with macro- and micronutrients in order to develop treatment and prevention tactics of diet-related diseases, combined with reduced body weight.

Association of leptin with anthropometric indexes, dyslipidemia and carbohydrate metabolism in Kazakh adults


Leptin plays an important role in eating behavior, the central action of this hormone is the regulation of appetite and energy expenditure. Anthroponutritiology as a new scientific direction uses the methods of medical anthropology and nutritional science. The study of the relationship between the regulation of energy metabolism, taking into account constitutional features, and anthropometric parameters provides relevance in this direction. The purpose of the research was to study of the relationship between blood serum leptin level and body mass index (BMI) and indicators of lipid profile, carbohydrate metabolism in adult Kazakh population.

Material and methods. The sample of the prospective study was 109 persons aged 18-60 years, who were divided depending on BMI into 5 groups, randomized by age and sex. We measured anthropometric parameters and biochemical parameters: serum leptin concentration, fasting blood glucose, insulin, glycated hemoglobin, HOMA-IR, lipid profile (concentration of cholesterol, low and high density lipoproteins, triglycerides, atherogenic index).

Results. In the sample studied, we found that in Kazakh adults, serum leptin level correlated with BMI (ρ=0.57; p<0.01). The highest values were observed at a BMI greater than 40 kg/m2, amounting to 54.9 [33.3; 78.4] vs 10.0 [4.8; 23.1] ng/ml in overweight individuals (p≤0.005). In women, leptin levels were almost 2-fold higher than in men (24.2 vs 12.9 ng/ml, p≤0.001). No significant correlations of leptin level with age and lipid profile have been found. There was a positive association of leptin with insulin (ρ=0.28, p<0.01) and the HOMA-IR (ρ=0.21, p<0.05).

Conclusion. The study showed that leptin blood level is associated with constitutional features, the highest values were found in persons with a high degree of obesity. Perhaps this result is associated with leptin resistance. Diagnostic criteria of leptin resistance are currently poorly studied. Taking into consideration clinical and specific actions of leptin there is a place for its further study as a potential biomarker of obesity.

Prophylactic nutrition

Anti-inflammatory activity of high and low methoxylated apple pectins, in vivo and in vitro


One of the possible mechanisms of the anti-inflammatory action of pectins is associated with the inhibition of excessive pro-inflammatory activity of macrophages - the cells that regulate inflammation intensity and reparative regeneration. It has been found that pectins with a low degree of methyl esterification of the carboxyl groups of the galacturonan core of the macromolecule exhibit this effect. In addition to leukocytes, intestinal epithelial cells are also involved in the pathogenesis of inflammatory bowel diseases. However, to date, there have been insufficient studies of the effect of pectin methyl esterification on the inflammatory response of enterocytes. The aim of the research was to evaluate the effect of the degree of pectin methyl esterification on inflammation of the colon in mice after oral administration and on the inflammatory response of human colon epithelium cells of the Caco-2 line in vitro.

Material and methods. In a prospective study, 40 male BALB/c mice weighing 20-25 g were used, 10 animals in each group. Solutions of apple pectins (200 mg/0.2 ml) were orally administered to mice through a plastic catheter 24 h before the induction of colitis. The control mice received water, and prednisone administration at a dose of 5 mg/kg of body weight was used as a positive control. Colon inflammation in mice was induced by a single rectal administration of 5% acetic acid (0.1 ml). A day later, the degree and area of the lesion was assessed using a light microscope, the activity of myeloperoxidase in the wall of the colon was determined by spectrophotometry. The effect of pectins on metabolic activity, intercellular permeability, Tumor Necrosis Factor a generation and alkaline phosphatase (ALP) activity in Caco-2 cells was assessed.

Results. It was found that low-methyl esterified pectin AU701, which contains more than 70% of free carboxyl groups, inhibited colon inflammation in mice. High methyletherified pectin AU201, in which more than 70% of the carboxyl groups are replaced by methyl ester, didn’t affect inflammation. It was revealed that pretreatment of Caco-2 cells with AU701 and AU201 pectins prevented lipopolysaccharide-induced increase in intercellular permeability and reduced the pro-inflammatory response of Caco-2 cells to LPS. After incubation of Caco-2 cells with AU701 pectin, the rate of hydrolysis of β-nitrophenylphosphate (an alkaline phosphate substrate) increased by 40%. Pectin AU201 had no effect on the alkaline phosphatase activity of enterocytes.

Conclusion. Thus, it was found that low-methyl esterified pectin AU701 inhibits inflammation both in vivo and in vitro. High-methyl esterified pectin AU201 suppresses pro-inflammatory reactions only in vitro. The ability of pectins to inhibit intestinal inflammation has a multifactorial nature, and is due, inter alia, to their ability to stimulate the expression of alkaline phosphatase by enterocytes.

Food quality control and safety

Synephrine in dietary supplements and specialized foodstuffs: biological activity, safety and methods of analysis


Synephrine is a natural protoalkaloid of the bitter orange Citrus aurantium L., it has structural similarity to ephedrine and adrenaline. Synephrine in the form of bitter orange extract is widely used as an ingredient of dietary supplements (DS) and specialized foodstuffs (SF) intended for weight loss and fitness improvement. Along with thermogenic and lipolytic effects, synephrine can cause cardiovascular side effects, especially when combined with caffeine and physical activity. This aspect is important, insofar as the main consumers of weight loss products are overweight people who are at risk of developing cardiovascular diseases.

The aim of the research is a hygienic assessment of the usage of bitter orange extract and synephrine in DS and SF, which includes an analysis of approaches to technical regulation in the Russian Federation and abroad, a review of data on biological activity, safety, types of adulteration and methods for the determination of citrus protoalkaloids.

Results. The adrenergic effect of bitter orange is caused by the presence of R-(-)-p-synephrine, making up about 90% or more of the total protoalkaloids. Dry bitter orange fruit extracts, standardized to synephrine content, which can vary from 4 to 98%, are used in the production of DS and SF. Synephrine is a weak adrenergic agonist, acting primarily through β3-adrenergic receptors, stimulating lipolysis. Because of insufficient safety data, the consumption of synephrine is regulated in the Russian Federation and abroad. The upper permissible level of synephrine consumption in the Russian Federation is 30 mg per day. Various cases of adulteration of DS and SF for weight loss and sport nutrition have been revealed: undeclared addition of synephrine in the form of bitter orange extract, addition of synthetic synephrine, its isomers or analogs. The main method for the determination of synephrine and other biogenic amines in DS and SF is high performance liquid chromatography with ultraviolet and/or mass detection.

Conclusion. The data presented in the review confirm the feasibility of developing an official method for determination of main protoalkaloids and monitoring of DS and SF for the content of synephrine and other citrus protoalkaloids on its basis.

Index of articles

Index of articles published in the journal «Problems of nutrition» for 2021


All articles in our journal are distributed under the Creative Commons Attribution 4.0 International License (CC BY 4.0 license)

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Viktor A. Tutelyan
Full Member of the Russian Academy of Sciences, Doctor of Medical Sciences, Professor, Scientific Director of the Federal Research Centre of Nutrition, Biotechnology and Food Safety (Moscow, Russia)

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