The year 2020 will be remembered by a never before seen, at least by our generation, global pandemic of COVID-19. While a desperate search for effective vaccines or drug therapies is on the run, nutritional strategies to promote immunity against SARS-CoV-2, are being discussed. Certain fermented foods and probiotics may deliver viable microbes with the potential to promote gut immunity. Prebiotics, on their side, may enhance gut immunity by selectively stimulating certain resident microbes in the gut. Different levels of evidence support the use of fermented foods, probiotics and prebiotics to promote gut and lungs immunity. Without being a promise of efficacy against COVID-19, incorporating them into the diet may help to low down gut inflammation and to enhance mucosal immunity, to possibly better face the infection by contributing to diminishing the severity or the duration of infection episodes.
Background
Coronavirus disease-19 (COVID-19) is an infectious disease transmitted by the virus responsible for the severe acute respiratory syndrome 2 (SARS-CoV-2).
Scope and approach
This review aimed to provide insights and perspectives for the use of probiotics, prebiotics, synbiotics, and postbiotics related to prevention/treatment and/or modulation of the microbiota in COVID-19 patients. Eighty-four studies published in the Scopus database from the onset of the pandemic until December 2021 were assessed and submitted to a bibliometric analysis adapted from VOSviewer software.
Key findings and conclusions
Through bibliometric analysis, it might be suggested that the modulation of the gut/lung microbiome is promising as an adjuvant for the prevention/treatment of COVID-19 patients, due to immunomodulation properties related to probiotics and prebiotics. So far, few clinical studies involving the application of probiotics to combat COVID-19 have been completed, but reduction in the duration of the disease and the severity of symptoms as fatigue, olfactory dysfunction and breathlessness, nausea and vomiting and other gastrointestinal symptoms were some of the main findings. However, probiotics are not recommended to immunocompromised patients in corticosteroid therapy. The future perspectives point to the modulation of the intestinal microbiota by probiotics, prebiotics, synbiotics, and postbiotics represent a promising adjuvant approach for improving the health of patients with COVID-19.
Strenuous physical activity, sleep deprivation, and psychological stress are common features of military field training. This study aimed to evaluate the effects of supplementation with a synbiotic ice cream on salivary IgA, gastrointestinal symptoms, well-being indicators, and gut microbiota in young military participants undergoing field training. Sixty-five military completed the study: one group was supplemented for 30 days with synbiotic ice cream containing: 2.1x108 CFU/g for L. acidophilus LA-5 and 2.7x109 CFU/g for B. animalis BB-12 and 2.3g of inulin in the 60g of ice cream at manufacture, and the other with a placebo ice cream. Volunteers were evaluated at pre-supplementation (baseline), post-supplementation, and after a five-day military training. Bifidobacterium and Lactobacillus genera were measured in stool samples and both showed a higher differential abundance post-supplementation and training. Salivary IgA and gastrointestinal symptoms decreased at post-training in both groups (p<0.05; main effect of time); however, supplementation with synbiotic did not mitigate this effect. Tenseness and sleepiness were decreased in the synbiotic-treated group, but not in the placebo group at post-military training (p=0.01 and p=0.009, respectively; group x time effect). The other well-being indicators were not affected by the synbiotic supplementation. In conclusion, 30 days of synbiotic ice cream supplementation containing inulin, L. acidophilus LA-5, and B. animalis BB-12 favourably modulated gut microbiota and improved tenseness and sleepiness in healthy young military undergoing a 5-day field training. These improvements may be relevant to this population as they may influence the decision-making process in an environment of high physical and psychological stress.
Purpose
The purpose of this paper is to evaluate perceived sensory differences of organic and conventional leafy green vegetables through three sensory tests – blind, informed and inverted and the willingness to buy (WTB) them, and associated factors of organic food consumption by these students.
Design/methodology/approach
The research had a cross-sectional design with university students. First, a questionnaire with 16 statements was presented to 233 consumers with a five-point Likert scale response. The assertions were categorized into five domains: trust in organic production; trust in conventional production; positive attitude to organic; affordable price; and perceived quality. Afterwards, a hedonic scaling was conducted with 150 consumers, 50 in each type of test with conventional and organic leafy green vegetables: lettuce (Lactuca sativa L.); kale (Brassica oleracea L.); common chicory (Cichorium intybus); and endive (Cichorium endivia). Visual aspect, taste, texture, bitterness and overall liking for all samples were evaluated on a nine-point hedonic scale.
Findings
In general, the participants did not perceive sensory differences during the blind test, but when the information about the vegetables was provided, higher scores were obtained by those products labelled as organic in the informed test and in the inverted test (conventional labelled as organic). This effect was higher for students with stronger attitudes towards organic food. These results indicated that the perceived differences between organic and conventional leafy green by university students tended to be attitudinal and, therefore, can be greatly influenced by the information provided with the product.
Originality/value
This research showed that university students were influenced by the organic label, revealing their sensory perception about vegetables. This study had multiple methodological approaches, including hedonic scaling and consumers’ WTB. This combination allowed identifying the students’ attitudinal tendency in relation to their sensory perceptions of organic green leafy green vegetables.
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