Вопросы питания № 5 2024

Problems of Nutrition

scientific and practical journal

Included in the List of the leading peer-reviewed journals and publications recommended by the Higher Attestation Commission (HAC) of the Ministry of Education and Science of the Russian Federation for publication of the results of theses for the degree of candidate or doctor of science.


Content
5 . 2024
Reviews

Vitamins K1 and K2 in children’s nutrition

Abstract

Vitamin K comes in several forms in foods. Phylloquinone (vitamin K1) is found in plant foods. Menaquinones (vitamin K2) are a class of vitamin K compounds found in animal products and fermented foods.

The purpose of the research was to characterize the role of vitamins K1 and K2 in the nutrition of children and to assess vitamin K status in children.

Material and methods. The literature review in recent years was carried out using the RSCI, Pubmed databases, as well as Google Scholar system using the keywords: «vitamin K», «vitamin K1», «vitamin K2», «menaquinone» and «phylloquinone» in combination with «children», or «breast milk».

Results. Vitamins K1 and K2 are interchangeable in relation to the formation of blood coagulation factors, but the effectiveness of vitamin K2 is much higher in the post-translational modification of extrahepatic proteins that provide antioxidant, epigenetic effects. Current vitamin K intake recommendations only apply to phylloquinone. Breastfed children are at risk for vitamin K deficiency, because breast milk content of vitamin K, mainly in the form of phylloquinone, is low. In adapted milk formulas for infant feeding, the content of vitamin K1 is significantly higher than in breast milk. To provide infants with vitamin K2, it is extremely important to promptly introduce complementary foods into the diet that are sources of menaquinones. Specifically formulated for the nutritional needs of young children products that contain naturally formed during milk fermentation vitamin K2, deserve special attention.

Conclusion. Considering the important role of vitamin K in the prevention of the skeletal system and cardiovascular diseases, it is necessary to increase its consumption by including fermented foods naturally containing menaquinones (MK-7) in the diet.

Physiology and biochemistry nutrition

Analysis of vitamin A and thyroid blood levels in the indigenous and local Caucasian population of the Arctic

Abstract

Previously, differences in the thyroid profile of Arctic residents were shown depending on the vitamin A blood level. However, dietary habits and metabolism peculiarities in the aboriginal and Caucasian representatives of the North population may be the cause of different retinol supply and therefore be one of the reasons for changes in their thyroid activity.

The purpose of the research was to assess vitamin A and thyroid blood levels in the aboriginal and local Caucasian population representatives of the Russian Arctic territories.

Material and methods. In the single-center observational cross-sectional study, apparently healthy residents of villages in the Arkhangelsk region were examined (n=281): 145 representatives of the local Caucasian population and 136 representatives of the aboriginal population, with the proportion of tundra nomadic aborigines at 34%, village aborigines at 66%. Vitamin A blood serum level was determined by the fluorometric method, and the thyroid content [thyroid stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), free T4, free T3] was determined by enzyme immunoassay. The integral thyroid index (ITI) as well as the index of peripheral conversion of iodothyronine (IPC) total and free fractions were calculated.

Results. The level of retinol in the indigenous population of the Arctic was lower than that in the local Caucasian population (1.84 [1.26; 2.56] versus 2.10 [1.70; 2.42] μmol/L, p=0.014). However, its deficiency was found only in village aborigines (20.5% of women and 11.8% of men). At the same time, they have the maximum tension of the pituitary-thyroid system: lower level of free T3 and free fractions’ IPC than in the nomadic and Caucasian population, and TSH levels were higher than in the Caucasian population. Increased vitamin A levels prevailed among the nomadic population: in 60.7% of men and 11% of women retinol level exceeded the norm. At the same time, they have increased metabolic activity of thyroid hormones: higher levels of free T3 and free fractions’ IPC compared with sedentary aboriginal population. No pronounced features of the thyroid profile were found in local Caucasians at normal blood concentrations of vitamin A.

Conclusion. The lowest retinol levels are observed in settled aborigines (especially young women) living in villages and experiencing the greatest transformation of traditional lifestyle and nutrition, which is combined with higher TSH blood levels and decreased thyroid hormone metabolism. The highest retinol levels were found in nomadic aborigines (especially young men), which increase the reserves of antioxidant defense and support high metabolism of thyroid hormones. However, the high percentage of people with excessive vitamin A blood level in this group raises concerns due to the possible negative consequences. Therefore, it is necessary to monitor fat soluble vitamin levels among Arctic aboriginal populations. Social support measures should be taken for settled residents of villages, enabling them to consume more traditional foods rich in vitamin A. The causes of excessive blood retinol in nomadic aborigines require further study and control.

Protective effect of soy proteins under excessive amount of fats in the diet of rats

Abstract

Excessive fat intake causes the development of metabolic syndrome (MS). Our studies have shown that soy proteins in the diet improve vascular reactivity in rats with a high-salt dietary load and renal dysfunction. We hypothesized that the introduction of soy proteins into a high-fat diet (HFD) can prevent or reduce vascular dysfunction.

The aim of the study was to test the hypothesis about the possible protective effect of soy protein isolate on endothelium-dependent dilation of the mesenteric arteries of male Wistar rats receiving an excess amount of fat in the diet.

Material and methods. The study used 3 groups of 20 rats, weighing 220–240 g. The HFD group received a diet containing 50% fat (by calorie value) and 20% casein, HFD + Soy group received a diet containing 50% fat and 20% soy isolate SUPRO-760, the control group – a standard casein diet. After 8 weeks, the responses of mesenteric arteries precontracted with phenylephrine to acetylcholine (ACh) were studied in the absence and with the use of NO synthase (L-NAME), cyclooxygenase (indomethacin), BKCa and Kv channel (tetraethylammonium) blockers, using microphoto- and video recording of the vessel diameter in vivo.

Results. Compared with the standard diet, visceral fat mass increased by 54.6% in rats fed HFD and by 25.9% in rats fed HFD + Soy (p<0.01). In the HFD + Soy group, the increase in blood pressure was less than in the HFD group (p<0.01). Consumption of HFD + Soy prevented disorders typical of HFD, reducing glycemia and insulin resistance, normalizing lipid metabolism (p<0.05). Evaluation of the functional state of the mesenteric arteries (in vivo) showed that in the HFD + Soy group the amplitude of dilation on ACh remained close to the control group, whereas in the HFD group the suppression of ACh-induced relaxation was observed (by 19.8% (p<0.01). After blockade of NO synthase by incubation with L-NAME the magnitude of vasodilation on ACh decreased (p<0.001) in the HFD group by 47.0±7.4%, in the HFD + Soy group – by 68.2±6.6% and in the control group – by 68.9±5.6%. After incubation with L-NAME, indomethacin and tetraethylammonium, the amplitude of dilation on ACh in rats of the HFD and HFD + Soy groups was 1.5 fold greater (p<0.05) than in the control. The relaxation amplitude to sodium nitroprusside did not differ between the groups.

Conclusion. The introduction of soy proteins into a HFD prevents the development of impairs characteristic of MS: it reduces visceral obesity, improves the state of carbohydrate and lipid metabolism, and has a hypotensive effect. The protective effect of soy proteins on vascular reactivity in rats with excessive fat consumption was confirmed: the introduction of soy protein isolate into the diet leads to the prevention of endothelial dysfunction characteristic of HFD, preventing the disruption of NO-dependent vasodilation mechanisms. It is assumed that the positive effect of soy on vascular reactivity is mediated by maintaining NO synthesis by the endothelium, and may be associated with the anti-inflammatory and antioxidant properties of both proteins and isoflavonoids contained in soy.

Nutrition of sportsmеn

Comparative assessment of the basal metabolic rate in athletes with different level of physical activity based on prediction equations

Abstract

The use of laboratory methods for assessing energy expenditure in athletes requires the availability of appropriate equipment and trained personnel, which is very difficult in the context of everyday sports activities. Therefore, the use of predictive equations that most accurately reflect energy expenditure is of paramount importance for developing dietary and recovery recommendations for athletes.

The purpose of this research was to compare the basal metabolic rate (BMR) of highly skilled athletes obtained using predictive equations.

Material and methods. The results of the examination of 180 elite athletes, members of the Russian national teams in four sports (shooting, biathlon, bobsleigh, snowboarding), of both sexes (107 men and 73 women aged 18 to 30 years), conducted in the morning, on an empty stomach, 10–12 hours after training, were analyzed during the pre-competition period of sports training. BMR was assessed using the InBody 720 bioimpedance analyzer (Katch–McArdle formula) and calculated using Mifflin–St Jeor, Cunningham, De Lorenzo and Harris–Benedict predictive equations. Lean body mass (LBM) was determined using an InBody 720 bioimpedance analyzer and calculated using Boer, Hume and James predictive equations.

Results. When assessing the BMR in athletes, the lowest values were obtained using the Katch–McArdle equation which is built into the InBody 720 analyzer. The highest values for men were obtained using the De Lorenzo equation, they exceeded the calculated values obtained using the Harris–Benedict, Mifflin–St Jeor and Katch–McArdle equations by 3.9–15.5% (p<0.05). In the female groups, the highest BMR values were obtained using the Mifflin–St Jeor equation; they exceeded the data calculated according to the Katch–McArdle, Cunningham and Harris–Benedict equations by 13.8–30.8% (p<0.05). The Cunningham formula, which is used to calculate the BMR based on the LBM, showed significantly higher values compared to the Katch–McArdle formula (p<0.05), the differences were about 180 kcal for the male groups and about 160 kcal for the female groups. In male athletes, the lowest LBM values were obtained using the Hume equation. These values were significantly lower (р<0.05) than the results of LBM calculation using the Boer and James equations (by 5.4–8.3%), as well as when assessing LBM using the InBody 720 analyzer (by 7.1–7.7%). In female sports groups, the lowest LBM values were obtained using the hardware method, while calculations using predictive equations showed higher values (the maximum LBM values using the Boer equation), but the differences were not statistically significant.

Conclusion. When using prediction equations to assess the BMR in athletes of different specializations, it should be taken into account that the results may differ by 3.9–15.5% when assessed in male groups and by 13.8–30.8% in female groups. Since the BMR is the starting point for calculating an athlete’s needs for nutrients and energy, it is recommended to use equations that take into account body composition, namely the content of LBM, or use a bioimpedance analyzer. BMT can also be calculated using prediction equations if a body composition analyzer is not available, but it should be taken into account that there are differences between the measured and calculated values of this indicator.

The effect of intaking a new sport food on milk and fruit basis on blood biochemical indicators and antioxidant status in athletes

Abstract

The problem of developing special food with targeted medical and biological properties is a pressing issue not only for sports medicine, but also for nutrition science.

The aim of the research was to provide a medical and biological justification for the development and to evaluate the effectiveness of using new sport food (SF) in the form of a bar.

Material and methods. The milk-fruit bar was developed on the basis of dry goat milk, dry whey, fruit and berry and grain raw materials, hydrolysate and isolate of plant and animal proteins, vitamin premix, as well as dry cultures of lacto- and bifidobacteria Bifidobacterium bifidum BB79, Streptococcus lactis SL215, Lactobacillus acidophilus LA72 (in a 1:1:1 ratio). The assessment of the effectiveness of a SF was carried out on 2 groups of professional athletes involved in martial arts (MMA), Greco-Roman wrestling, triathlons and pentathlon. 42 athletes were included in the control group and 46 athletes were included in the main group. Athletes in the main group consumed 4 milk-fruit bars (120 g) daily in addition to their basic diet, while athletes in the control group received placebo bars equivalent in calorie value (150 g). The complex examination before and after a 21-day training cycle, in combination with SF intake, included the study of body composition, hematological (red blood cells, hemoglobin, leukocytes, lymphocytes, erythrocyte sedimentation rate, hematocrit) and biochemical studies (plasma total protein, albumin, cholesterol, lactate) as well as studying the antioxidant status of athletes [malondialdehyde (MDA) and diene conjugates (DC) in blood serum].

Results. On the 21st day of SF intake, the cholesterol level decreased by 14.5–18.9% (p<0.05) in individuals involved in Greco-Roman wrestling, MMA and triathlon, in athletes involved in pentathlon – by 11.3% (p>0.05) compared to the initial level in blood plasma. Lactate level also lowered in athletes involved in Greco-Roman wrestling and triathlon by 14.2–28.3% (p<0.05), in other sports – by 12.2–17.6% (p>0.05). At the same time, these indicators did not change significantly in athletes from the control group. In addition, the lactate level in triathletes at the end of the study was 23.2% lower compared to the level in athletes from the control group (p<0.05). SF intake led to the decrease (p<0.05) in blood serum of athletes involved in the presented sports of MDA level by 20.0–27.9% (except for triathletes) and of DC – by 14.3–48.5% (except for athletes involved in Greco-Roman wrestling). In athletes of the control group after taking a placebo bar, the level of MDA significantly decreased by 20.0% only in individuals involved in MMA.

Conclusion. The developed SF can be recommended for nutrition of athletes involved in various sports.

Hygiene of nutrition

Long-term and seasonal dynamics of vitamin D supply indicators for the population of the Western Siberia region

Abstract

Despite the active study of vitamin D, today the problem of its insufficient supply remains relevant both in Russia and throughout the world. In our country, the situation is affected by the geographical, climatic, as well as ethnic and cultural characteristics of each region. It is of interest to assess the temporal and territorial characteristics of the population’s sufficiency.

The purpose of the study was to analyze long-term and intra-annual dynamics of vitamin D status among residents of the Western Siberia region for the correction of prevention programs.

Material and methods. An analysis of the vitamin D status in the residents of Western Siberia, located at 53–58° northern latitude, was carried out. The study was carried out among adults aged 18 to 93 years, the median age was 49 [36; 62] years (n=2586). Vitamin D status was determined by the level of 25(OH)D in venous blood serum. The determination was carried out using chemiluminescence immunoassay. Study period – 2017–2023.

Results. The results of the study demonstrate an improvement in vitamin D status in residents of Omsk region in dynamics. This is manifested in a decrease in the proportion of people with deficiency from 41.6±1.6% in 2017–2019 to 33.5±1.7% in the period 2022–2023 (p<0.001) and an increase in the proportion of the examined with optimal sufficiency from 26.7±1.4 to 38.2±1.8% (p<0.001). An obvious dependence of vitamin D serum level on the month of the year has been established: low values were noted in the winter and spring months with a minimum in March (18.4 [12.1; 27.9] ng/ml).

Conclusion. Seasonal variations are an important factor influencing 25(OH)D blood level. The decrease in the proportion of individuals with deficiency states most likely indicates an increase in vitamin D intake from food or supplements, which requires further study.

Unprocessed red meat consumption in the general working-age population: sociodemographic, behavioral and health-related determinants

Abstract

Anunbalanced diet, specifically excessive unprocessed red meat (RM) consumption, plays significant role in development of chronic non-communicable diseases. Modern research indicates excessive consumption of unprocessed red meat (RM) in the Russian population. There are reports of relationships between RM consumption and some factors, but it hasn’t been sufficiently studied.

The aim of the research was to study unprocessed RM intake and its relationship to socio-demographic, behavioral and medical factors in general population.

Material and methods. In the ESSE-RF cross-sectional study, data from 1.600 participants randomly sampled from unorganized population of 25–64 years old (59% women), average age 45.0±0.5 and 47.2±0.4 years for men and women, respectively, were studied. Standard questionnaire was used. Frequency of RM consumption was presented in 4 ranked categories from “do not use/rarely” to “daily/almost daily”. Associative analysis included socio-demographic, behavioral and health-related variables. Descriptive statistics, single- and multivariable ordinal regression were used.

Results. 52.1% of men and 41.9% of women consumed RM daily (p<0.001), one third of all – 1–2 times a week (p=0.737), 11.5% of men and 22.5% of women – 1–2 times a month or less (p<0.001). Odds for higher RM consumption were higher in men (OR=1.67; p<0.001). In men RM intake didn’t vary with age (p=0.796). Highest RM intake in women was observed at the age of 35–44 years, comparatively lower at 25–34 (OR=0.70; p=0.076), 45–54 (OR=0.63; p=0.012) and 55–64 years old (OR=0.42; p<0.001), respectively. In multivariable analysis, prosperity level (women), physically active work, marital status, living in own housing showed a direct, whereas presence of carotid atherosclerotic plaques (women) and walking ≥45 min – inverse association with RM consumption, accordingly.

Conclusion. With age, the frequency of RM consumption was relatively constant in men and decreased in women after 45 years. The frequency of RM consumption was directly correlated with male gender, physical activity during work, marital status (married/common-law marriage), residence in one’s own house, income level (for women) and inversely correlated with walking ≥45 min during free time. Less frequent RM consumption in women was associated with the presence of carotid atherosclerotic plaques. No independent associations with chronic alimentary diseases and other risk factors for cardiovascular diseases has been found. The data obtained indicate the need to increase public awareness concerning the role of RM in the development of chronic non-communicable diseases, and to develop tools reducing RM intake and increasing share of other protein sources in the diet.

Analysis of the influence of enzyme preparations produced using technological microorganisms on the microbiome and cellular immunity of rats

Abstract

The observed increase in the production of enzyme preparations (EP) using mutant and genetically modified microorganisms makes it necessary to assess their risks to consumer health. However, at present, their possible influence on the microbiome, immune status of the macroorganism has not been sufficiently studied.

The purpose of the research was to assess the effect of two EP – the complex of hydrolases with proteolytic and nuclease activity from the Aspergillus oryzae RCAM 01134 mutant strain (EP1) and the neutral protease – bacillolysin and serine protease from the Bacillus subtilis-96 (VKM B-3499D) mutant strain (FP2) on the intestine microbiome and cellular immunity indices of the experimental animals.

Material and methods. The experiment on the subacute toxicity of EP1 and EP2 was carried out for 30 days using Wistar rats (7 groups of 10 males each). EP was administered to animals intragastrically in doses 0 (control – saline solution); 1, 10 and 100 mg/kg body weight per day. The composition of the cecum microbiocenosis was studied by inoculating tenfold dilutions of the cecum contents on the differential diagnostic media. The quantitative content of short-chain fatty acids (SCFA – acetic, propionic, isobutyric, butyric, isovaleric, valerianic acids) in the colon contents was determined by high-performance gas chromatography. The expression of T- and B-lymphocyte and NK-cell receptors (CD45RА+, CD3+, CD161+, CD3+CD4+, CD3+CD8+) in rat peripheral blood was determined using an FC-500 flow cytometer.

Results. The data obtained as a result of the microbiocenosis studies of the cecum contents indicate that EP1 and EP2 administration had a reliable effect on the quantitative and qualitative composition of aerobic microorganisms, including opportunistic microorganisms, as well as it lead to a weak increase in the number of bifidobacteria and lactobacilli. The development of an inflammatory process in animals of all experimental groups have been caused by the changes in the qualitative and quantitative composition of various groups of microorganisms in the cecum contents, SCFA level in the faeces and indicators of cellular immunity under intragastric administration of FP1 and FP2 for 30 days.

Conclusion. The revealed difference in the composition of the cecum microbiocenosis, SCFAs produced by the intestinal microflora, and the cellular immunity indices of the experimental animals under EP1 and EP2 administration, in our opinion, is due to the spectrum of metabolites produced by the intestinal microflora, as well as strains of Aspergillus oryzae RCAM 01134 and Bacillus subtilis-96 (VKM B-3499D). The features of the relationship between the spectrum of SCFAs produced by the intestinal microflora, their quantity and the percentage of T- and B-lymphocytes in the blood of rats indicate different mechanisms of the influence of EP1 and EP2 on the microbiome and immune status of the macroorganism.

Rats’ reproductive function under toxic load against the background of protein deficiency

Abstract

Safety assessment approaches of novel food, currently adopted in the Russian Federation, imply mandatory in vivo reproductive toxicity tests with the study of reproductive function and offspring development in order to obtain comprehensive evidence of the absence of distant adverse effects that may manifest only in the next generation. Comprehensive study of reproductive function, pre- and postnatal offspring development, as a rule, includes the research of a large number of parameters, all of which has a wide range of physiological fluctuations, and the heterogeneous distribution of some parameters’ values complicates the interpretation of the results.

The purpose of the study was to investigate the efficiency of a reduced adaptive potential model in rats, based on decreased diet protein intake, for the use in reproductive toxicity experiments.

Material and methods. The research lasting 155 days was carried out on rats of F0 (180 females and 90 males) and F1 (773 pups, 456 fetuses) generations. Animals of parental generation F0 were divided into 3 groups – control, the 1st and the 2nd test groups, 30 males and 60 females in each. The initial age of F0 rats was 28–35 days. Animals of all groups during growth and sexual maturation (25–90 days of life) received a diet with reduced protein content (9.4 g per 100 g of diet, which is 9% in calorie value). After reaching the age of physiological maturity (100 days) rats were transferred to a diet with lower protein content (6.1 g per 100 g of diet, 6% in calorie value), and received this diet during mating, pregnancy and feeding of F1 offspring. The rats of the test groups received with feed the model herbicide glyphosate (isopropylamine salt, concentration 360 g/l) at a dose of 0.3 g/kg body weight (6% of LD50): the 1st test group – from day 70 of life, the 2nd test group – from day 30 of life throughout the duration of the experiment. Reproductive function was evaluated by the fertility of F0 animals and by the character of prenatal and postnatal development of F1 offspring.

Results. The toxic factor’s influence on the background of reduced protein supply did not lead to complex changes in the reproductive function of rats, the test groups differed from the control group only by the post-implantation loss and the mean litter size in the postnatal period: post-implantation loss in the 1st and the 2nd test groups was higher than normal, exceeding the value of this indicator in the control group (4.7±1.6%) by 3.1 (p<0.05) и 2.2 (р>0.05) times; the mean litter size in the 1st and the 2nd test groups was by 15.8 and 21.3% (р<0.05) lower than in the control group. Survival rate of offspring during the 1st month of life in all groups was at least 72%, which corresponds to the lower limit of the norm characteristic for Wistar rats.

Conclusion. The use of the alimentary model of adaptation potential reduction based on diet protein deficiency does not consider appropriate in reproductive toxicity studies, since it does not increase either the severity of the reaction to toxic effects or the reliability of the results obtained. This model can be recommended for subacute toxicological studies of low-toxicity objects, in particular, when assessing the safety of novel food.

Identification of meldonium in the urine of volunteers using high-performance liquid chromatography-tandem mass spectrometry after consumption of milk of cows treated with a preventive course of the veterinary drug Emidonol®

Abstract

Emidonol is a Russian antioxidant drug, widely used in veterinary medicine both for prophylactic purposes and under pathological conditions associated with oxygen deficiency. The product of its biotransformation in animals is meldonium, which is a metabolic modulator and has been included on the Prohibited List by the World Anti-Doping Agency (WADA) since 2016. In the presented research, volunteers once consumed samples of milk from cows that had undergone a 15-day course of the veterinary drug Emidonol® 10%, obtained from one of the farms in the Moscow region.

The purpose of our research was to study the possibility of qualitative determination of meldonium in urine samples after drinking a large amount of milk using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and to assess duration of urinary excretion of the prohibited in sport metabolism modulator in accordance with WADA identification criteria.

Material and methods. Milk samples were collected from the cows on the 15th (last) day of the injection course of the veterinary drug Emidonol® 10%. Urine samples from volunteers, collected before and within 48 hours after a single intake of 900 ml of fresh cow’s milk have been examined. The volunteers (n=4, aged 35–52 years, body weight 65–93 kg, gender was not taken into account) had not previously taken meldonium, any dietary supplements, as well as milk, dairy and meat products within 4–5 days before submitting a blank sample and during the study. Sample preparation of urine specimens was carried out using the “dilute and shoot” method. The HPLC-MS/MS was used for analysis. Meldonium identification was carried out in selective reaction monitoring (SRM) mode using the following transitions and collision energies: 147.1>147.1 (15), 147.1>132.1 (17), 147.1>59.1 (17), 147.1>58.1 (17), 147.1>42.1 (60).

Results. It was found that meldonium is reliably determined in urine samples of volunteers after 12 hours when identified by HPLC-MS/MS using the 5 above-mentioned SRM transitions, and for 36–40 hours using the transitions 147.1>59.1 (17), 147.1>58.1 (17) after a single consumption of 900 ml of milk. The peak concentrations occur at 5–10 hours after administration (estimated concentration in urine from 160 to 400 ng/ml) with a subsequent decrease to 2.5–5 ng/ml and below after 36–40 hours. The excretion profiles of the prohibited modulator in urine are presented.

Conclusion. The principal possibility of qualitative determination of meldonium in urine samples of volunteers over 36–40 hours with a single consumption of large quantities of milk from cows that have undergone a course of treatment with the veterinary drug Emidonol® 10% was demonstrated.

Child Nutrition

Dairy kitchens in besieged Leningrad (1941–1944)

Abstract

Retrospective analysis of medical and organizational problems of food supply in besieged Leningrad is important for the development of the principles of population nutrition in extreme situations.

The aim of the paper was to characterize the work of dairy kitchens that provided nutrition to infants in Leningrad during the blockade years (1941–1944) on the basis of documentary data.

Material and methods. The study was prepared on the materials of the archives of St. Petersburg, considered from the position of the social history of medicine, which is centered on the study of medical practice.

Results. In the blockaded Leningrad under the conditions of food, electricity, and water supply shortages, there was a forced abandonment of a number of principles of infant feeding generally recognized by the pediatricians. Almost all infants born in the blockade ring were transferred to artificial feeding with the release of infant formula through milk kitchens. In conditions of food shortages, children under the age of three were also provided with centralized milk products. The activities of the staff of the milk kitchens were carried out in close contact with doctors of regional children’s consultations and specialists of the Leningrad Pediatric Institute, who developed issues of rational nutrition for infants. During the blockade years, the formulae developed before the war were generally retained, but due to the lack of dairy resources, vegetable products were used as substitutes. As the food situation in the city improved, doctors and milk kitchens reverted to pre-war recipes, especially for infant nutrition. The products of the milk kitchens were subject to constant supervision by sanitary physicians. Laboratory tests indicated that, in terms of basic microbiological indicators, infant formulae were generally safe and differed slightly from those produced before the war.

Conclusion. In blockaded Leningrad (especially during the winter of 1941/1942), the products of dairy kitchens served, as a rule, as the only source of nutrition for infants. Despite a number of organizational difficulties and abuse of workers, the preservation of the network of milk kitchens, centralized supply of milk and formula through them, and expansion of the contingents attached to them justified themselves.

Modern approaches to studying child nutrition issues by students and doctors using digital interactive technologies

Abstract

Digital interactive learning is spreading across many medical specialties, using a variety of methods: from problem-solving simulators to standardized patients, from computer modeling to mannequins.

The purpose of the study was to analyze innovative approaches to independent work when studying issues of child nutrition by pediatric students and practicing doctors.

Material and methods. The pediatric simulator, developed by the Higher School of Education and Science in collaboration with the teaching staff of seven medical universities in Russia, allows you to train and test students in conditions close to real ones, and to reinforce the issues of child nutrition. An analysis of the effectiveness of organizing online education among students (n=150, 15.7% boys, 85.3% girls, average age – 20.0±1.4 years; duration – February–May 2020) of the 3rd year of Sechenov and Smolensk Medical Universities was carried out using a single-blind randomized controlled trial. Using Google forms, the questionnaire was created with questions regarding the respondents’ attitude towards distance learning. The effectiveness of distance learning on the studied simulator was analyzed for 84 students (n=48 – main group, n=36 – control group), a case analysis was carried out with the prescription of the diet therapy to a virtual patient with the lactase deficiency.

Results. In two modes of the program (training and testing) the imitation of a dialogue with a virtual 3D patient, examination, diagnosis and treatment, including diet therapy were implemented. A number of diet therapy algorithms are presented in additional illustrations. The use of a children’s simulator with a 10-point assessment system showed greater effectiveness in mastering practical skills in the main group compared to the control group. The students who mastered the digital simulator indicated satisfaction in acquiring new knowledge and skills, increased motivation to learn and gain practical skills in examination, supervision and prescription of the diet therapy, approaching 6–9 points (р=0.005). For the control group, the questionnaire showed consistently low results (p<0.05). Analysis of the prescription of the diet therapy in a situational task showed good and excellent results for all students of the main group.

Conclusion. The interactive digital simulator has shown high efficiency in training future pediatricians. Clinical cases help develop practical skills and build professional competencies, including child nutrition issues.

CHEMICAL COMPOSITION OF FOODSTUFFS

Comparison of the nutritional structure of patients with non-alcoholic fatty liver disease with the most significant nutrition patterns for health

Abstract

Impaired nutritional patterns in patients with non-alcoholic fatty liver disease (NAFLD) are considered to be one of the causes of the disease, with certain types of nutrition having a pronounced protective effect on the incidence of NAFLD.

The aim of the study was to compare in detail the nutritional characteristics of Russian patients with NAFLD compared with hepatoprotective dietary patterns (Mediterranean, vegetarian diet, DASH diet).

Material and methods. As the research material, data from the examination of 613 patients of the Federal Research Centre of Nutrition, Biotechnology and Food Safety, obtained in the period from 2021 to 2023, were used. The assessment of the stage of liver steatosis and fibrosis was carried out using vibration-controlled transient elastography. The patients were divided into 2 groups: the NAFLD group (n=367) and the control group (n=205), and pairs (n=77) of these groups were formed by gender, age and BMI. Nutrition was assessed using a semi-quantitative method of analyzing food consumption over the previous 1 month. Consumption of food groups by the studied groups was compared with intake in dietary patterns associated with reduced risk of NAFLD.

Results. Analysis of the consumption of food groups in the diets of patients with NAFLD along with patients from the control group showed that their intake differed from the recommended levels of consumption according to the healthy eating pyramid and protective dietary patterns for NAFLD with lower consumption of milk and dairy products (Me=0.8–1.1 vs 1.8–4.2 cups/day), legumes (Me=0.16–1.19 vs 1.5–7.5 cups/day), vegetable oils [Me=7.0 g/day in patients with NAFLD and Me=5.0 g/day in patients from the control group (p=0.04) vs 24.0–40.0 g/day], fish and seafood (Me=6.2–6.6 vs 6.3–17.6 ounces/week), vegetables (Me=1.9–2.0 vs 2.5–4.0 cups/day), nuts and seeds (Me=3.5 vs 4.5–11.1 ounces/day), excessive consumption of products from the «meat, poultry, eggs» group (Me=3.0–4.1 vs 0.4–3.6 ounces/day), and corresponded to these recommendations in terms of the consumption of fruit and cereals (at the expense of white bread and bakery products).

Conclusion. Patients with NAFLD need to change the structure of habitual nutrition, including through the introduction of foods for special dietary uses capable of replenishing the missing nutrients in their diet, which have a protective effect against NAFLD.

Improving the technology for obtaining an ingredient with probiotic properties using a new complex proteolytic enzyme preparation

Abstract

The development of technologies for producing bacterial concentrates and enzyme preparations using domestic microbial strains is an urgent task. The use of whey protein hydrolysates as components of nutrient media for probiotic bacteria consortia for the cultivation of lactic acid and bifidobacteria makes it possible to improve and develop innovative processes for obtaining bacterial concentrates with the required functional properties for the production of dietary supplements. A consortium of probiotic microorganisms (lactic acid and bifidobacteria) was created in the All-Russian Scientific Research Institute of Food Biotechnology as a starter culture for specialized dairy products. Using strain Aspergillus oryzae 21-154 LAP a new complex enzyme preparation with a laboratory name Protoorizin LAP has been obtained providing the extensive hydrolysis of protein substrates.

The purpose of the research was to evaluate the possibility of using the new domestic proteolytic enzyme preparation Protoorizin LAP in preparing whey-based nutrient media for culturing a consortium of probiotic microorganisms to obtain bacterial concentrates.

Material and methods. The object of the research was a symbiotic consortium, including lactic acid bacteria strains (Lactobacillus delbrueckii ssp. bulgaricus Д-16, Lactobacillus plantarum 578/25, Lactobacillus helveticus 842(D)-2, Lactococcus lactis subsp. lactis М-12, Streptococcus thermophilus В-92) and bifidobacteria (Bifidobacterium longum Б-2). Unclarified curd whey and whey protein concentrate were taken as the nutrient medium basis. The media were treated with β-galactosidase to reduce the lactose content. In order to hydrolyze proteins, the control culture medium was treated with commercial preparations: serine protease – Alcalase® 2.4 L and leucine aminopeptidase – Flavourzyme® 1000 L. In the experimental medium, two imported preparations were replaced with a laboratory sample of the enzyme preparation Protoorizin LAP. In the prepared nutrient media, the content of amine nitrogen, free amino acids and soluble protein was determined, and electrophoretic analysis of proteins and peptides was carried out. The consortium growth was monitored by the content of dry substances and reducing sugars, by active and titratable acidity, as well as by microscopy. The number of viable cells of lactic acid bacteria and bifidobacteria at the end of fermentation and in the resulting bacterial concentrates were determined by sieving on the appropriate selective agar media using an automatic colony counter.

Results. The effectiveness of Protoorizin LAP in the hydrolysis of whey proteins significantly exceeded the result of the combined action of Alcalase® 2.4 L and Flavourzyme® 1000 L both in terms of reducing the undigested protein content, including immunogenic fractions, and in terms of the yield of soluble protein, amine nitrogen and amino acids. The nutrient media obtained using proteases ensured good growth and development of the probiotic consortium. Due to the high content of free amino acids, the dynamics of carbohydrate consumption, titratable acidity, and the number of viable cells were higher in the medium obtained using Protoorizin LAP than when using commercial preparations. At the same time, a high titer of probiotic strains and good cultural and morphological characteristics were obtained on all media. The experimental preparation Protoorizin LAP provided the increase in viability of bacterial cells after lyophilization.

Conclusion. The technological method that include application of the new proteolytic preparation Protoorizin LAP in preparing nutrient media based on whey proteins was developed. The method can be used in the technology of producing bacterial concentrates at the stage of culturing of the created lactic acid and bifidobacteria consortium. The bacterial concentrate can be recommended as a recipe ingredient in the manufacture of dietary supplements or foods for special dietary uses containing probiotics.

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CHIEF EDITOR
CHIEF EDITOR
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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