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Enhancing immunity in viral infections, with special emphasis on COVID-19: A review.
Jayawardena, R, Sooriyaarachchi, P, Chourdakis, M, Jeewandara, C, Ranasinghe, P
Diabetes & metabolic syndrome. 2020;14(4):367-382
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A healthy immune system is one of the most important weapons in relation to the current pandemic of COVID-19 where no effective preventive and curative medicine is available. The main aim of this study was to evaluate the evidence on enhancing immunity in viral infections. This review focuses on influenza-like viral infections; however, other studies on viral infections have also been included. It included 43 articles of which 13 were on vitamins, 8 on minerals, 18 on nutraceuticals and 4 on probiotics. Results indicate that: - vitamin supplementation, especially vitamin D may be beneficial in people who are either deficient or insufficient. - adverse effects of vitamin E supplementation on the immune response have been reported. - there are several beneficial nutraceuticals, however their efficacy and safety depend on their ingredients, as well as various other factors including, methods of extraction. - in addition to basic hygienic practices, proper dietary and lifestyle behaviours are essential for prevention and treatment of respiratory viral diseases. Authors conclude that achieving recommended amounts of calories and micronutrient will be a challenge and elective micronutrient supplementations may be beneficial especially for vulnerable populations such as the elderly.
Abstract
BACKGROUND AND AIMS Balanced nutrition which can help in maintaining immunity is essential for prevention and management of viral infections. While data regarding nutrition in coronavirus infection (COVID-19) are not available, in this review, we aimed to evaluate evidence from previous clinical trials that studied nutrition-based interventions for viral diseases (with special emphasis on respiratory infections), and summarise our observations. METHODS A systematic search strategy was employed using keywords to search the literature in 3 key medical databases: PubMed®, Web of Science® and SciVerse Scopus®. Studies were considered eligible if they were controlled trials in humans, measuring immunological parameters, on viral and respiratory infections. Clinical trials on vitamins, minerals, nutraceuticals and probiotics were included. RESULTS A total of 640 records were identified initially and 22 studies were included from other sources. After excluding duplicates and articles that did not meet the inclusion criteria, 43 studies were obtained (vitamins: 13; minerals: 8; nutraceuticals: 18 and probiotics: 4). Among vitamins, A and D showed a potential benefit, especially in deficient populations. Among trace elements, selenium and zinc have also shown favourable immune-modulatory effects in viral respiratory infections. Several nutraceuticals and probiotics may also have some role in enhancing immune functions. Micronutrients may be beneficial in nutritionally depleted elderly population. CONCLUSIONS We summaries possible benefits of some vitamins, trace elements, nutraceuticals and probiotics in viral infections. Nutrition principles based on these data could be useful in possible prevention and management of COVID-19.
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Beta Glucan: Supplement or Drug? From Laboratory to Clinical Trials.
Vetvicka, V, Vannucci, L, Sima, P, Richter, J
Molecules (Basel, Switzerland). 2019;24(7)
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Beta glucans, β-1,3-glucans (glucans) are chains of sugars (polysaccharides) naturally occurring in the cell walls of plants such as cereals, bacteria and fungi. They are gaining attention not only as an important food supplement but also as an immunostimulant and potential drug. It has been known since prehistoric times that mushrooms have medicinal properties. Glucans effect various branches of the immune system and there are numerous animal and human studies showing remarkable activity against a wide variety of tumours. This paper represents an up-to-date review of glucans and their role in various immune reactions and the treatment of cancer. It also cites studies showing their potential use for wound healing and skin health, chronic respiratory problems in children, alleviation of allergic problems and reducing cholesterol levels. Additional lesser-known effects of glucan include improvements in colitis, obesity, or Lyme disease The authors conclude that glucans are an important immunomodulator. They believe that glucans will soon move from food supplement to widely accepted drug.
Abstract
Glucans are part of a group of biologically active natural molecules and are steadily gaining strong attention not only as an important food supplement, but also as an immunostimulant and potential drug. This paper represents an up-to-date review of glucans (β-1,3-glucans) and their role in various immune reactions and the treatment of cancer. With more than 80 clinical trials evaluating their biological effects, the question is not if glucans will move from food supplement to widely accepted drug, but how soon.
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Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travellers: A Randomized, Double-Blind Placebo-Controlled Clinical Trial.
Tiralongo, E, Wee, SS, Lea, RA
Nutrients. 2016;8(4):182
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Long-haul air travel increases the occurrence of respiratory illnesses such as the common cold. Elderberries have anti-bacterial and anti-viral properties and previous studies have shown that an elderberry extract can reduce the duration and severity of cold and flu symptoms. This randomised controlled trial aimed to identify whether capsules containing a standardised elderberry extract are effective in preventing respiratory symptoms in travellers on long-haul flights. 325 healthy adults volunteered for the study. Participants were split into two groups: one group was given capsules each containing 300mg of Elderberry extract, and the other group was given placebo capsules. For both groups, participants were given 2 capsules a day for 10 days leading up to travelling, and 3 capsules a day during travel and for four to five days after reaching their destination. Participants completed health surveys 10 days and two days before travelling, and then again five days after. They also kept a daily diary of cold symptoms. Participants in both the placebo and elderberry group tended to experience an increase in respiratory symptoms after travelling. The elderberry group experienced less colds than the placebo group, although the difference was not statistically significant. Elderberry supplementation did however result in a reduction in symptoms, and shortened the cold duration by approximately two days compared to the placebo. The authors recommend that more clinical research with high quality elderberry preparations is carried out to better understand the health benefits of this traditional medicine.
Abstract
Intercontinental air travel can be stressful, especially for respiratory health. Elderberries have been used traditionally, and in some observational and clinical studies, as supportive agents against the common cold and influenza. This randomized, double-blind placebo-controlled clinical trial of 312 economy class passengers travelling from Australia to an overseas destination aimed to investigate if a standardised membrane filtered elderberry (Sambucus nigra L.) extract has beneficial effects on physical, especially respiratory, and mental health. Cold episodes, cold duration and symptoms were noted in a daily diary and assessed using the Jackson score. Participants also completed three surveys containing questions regarding upper respiratory symptoms (WURSS-21) and quality of life (SF-12) at baseline, just before travel and at 4-days after travel. Most cold episodes occurred in the placebo group (17 vs. 12), however the difference was not significant (p = 0.4). Placebo group participants had a significantly longer duration of cold episode days (117 vs. 57, p = 0.02) and the average symptom score over these days was also significantly higher (583 vs. 247, p = 0.05). These data suggest a significant reduction of cold duration and severity in air travelers. More research is warranted to confirm this effect and to evaluate elderberry's physical and mental health benefits.