Dr. Muhammad Torequl Islam :
The pandemic novel coronavirus 2019 (nCoV-19) breakout has caused infection to over 620,000 individuals and over 28,500 deaths in more than 198 countries across the world. The number of infected cases is grossly increasing daily. Unfortunately, there is no single vaccine and specific treatment(s) for it. A number of protective measures such as isolation, quarantine, social distancing, avoidance of large gatherings, avoidance close contact with people suffering from acute respiratory infections, frequent hand-washing, especially after direct contact with ill people or their environment, and avoiding unprotected contact with farm or wild animals have been suggested by the experts around the world. Respiratory and/or circulatory supports along with some other antiviral drug therapies have been also reported. However, along with the protection and treatment strategies, dietary supplements and nutritional behavior may help us to manage nCoV-19 infection in human. This writing focuses on the effects of dietary contents, especially the diets containing vitamins on the management of nCoV-19 infection.
Nutritional and pathogenic stress interact with the physiological malfunctions in animals, as these can lead to hepatic, cardiovascular, neurological and many other diseases. Diets that are rich in polysaccharides (e.g., cereals, onion, garlic, ginger, algae) along with protein and fat derived from fish and soy are necessary for healthy livlihood. Natural antioxidants such as quercetin and alliin are evident to increase the presence of Firmicutes genera, while decrease in Bacteroidetes and Proteobacteria in the intestine, therefore, reduces the incidence of inflammatory bowel disease. Diets containing high amount of unsaturated fatty acids (e.g., linolenic, linoleic, eicosapetaenoic, docoshexaenoic, and arachidonic acids), omega-3 and omega-6 fatty acids found in large qualities in fish and nuts, as well as low glycemic index carbohydrates, are evident to promote healthy metabolic profiles in human. Generally, foods containing high carbohydrate and fat, and low fiber have profound effects on the regulation of our immune system.
Diets modified seasonally or by biogeographic, demographic or cultural shifts may contain lower amounts of essential nutrients and can differentially influence mitochondrial bioenergetics, retrograde signalling to the nuclear genome, and anterograde signalling to mitochondria, alter the frequencies of mtDNA haplotypes and affect the health of human and other animals.
Food supplements may be a potential sources to manage the infection of nCoV-19. In a study, feed additives such as phosphoric acid, citric acid, or fumaric acid were found to reduce porcine delta CoV in infected pigs. In another study, chick embryo tracheal organ cultures showed increased resistance to infection by a CoV after exposure to ascorbate (also called vitamin C. Generally, vitamins act as modulators of immunological functions, including activation, proliferation and cytokine production by T cells.
Intestinal dendritic cells use vitamin A to produce retinoic acid, which activates the mucosal immune system, and displays a number of other important functions, including production of chemokines, adhesion molecules, and specific cytokines,promotes the differentiation and activation of intestinal effector cells, CD4+ FoxP3+ Treg cells, and IgA-producing plasma cells. The vitamins of B group also play important roles for immune system homeostasis and functions. Thiamine (vitamin B1) promotes accumulation of naive B cells in intestinal Peyer patches and induces IgA production in the intestinal mucosa. It also regulates leukocyte activation, proliferation, and production of pro-inflammatory cytokines upon antigenic stimulation. On the other hand, riboflavin (vitamin B2) deficiency has been evident to impart a negative effect on macrophage cell lines, decrease in cell adhesion, viability, production of reactive oxygen species, and phagocytic activity. Niacin (vitamin B3) has anti-inflammatory property. Pyridoxal phosphate (vitamin B6), a coenzyme necessary for carbohydrate, lipid, heme and amino acid metabolism. It has anti-inflammatory and anti-oxidant effects. In a study, a diet containing no B6 showed a decreased T cell proliferation, differentiation, and IL-2 production, with an enhanced IL-4 secretion after mitogenic stimulation in mice. Biotin (vitamin B7) deficiency leads multiple effects on the immune system as its deficiency is evident to inhibit the proliferation and maturation of B and T lymphocytes, thus decrease in antibody production by B cells and cytotoxic activity of natural killer (NK) and T cells. Folate (vitamin B9) interacts with vitamins B6 and B12, as well as homocysteine, in trans-methylation metabolic pathways that regulate various cell functions, including the response to oxidative stress. It also regulates pro-inflammatory and effector functions in leukocytes. On the other hand, cobalamine (vitamin B12) deficiency has been found to increase interleukin (IL)-6 production by peripheral blood mononuclear cells in Alzheimer disease patients.
Vitamin C is evident to manage common cold in experimental animals. A deficiency of this vitamin causes immune system dysfunction and increased susceptibility to infections. It promotes chemotaxis, phagocytic activity, and bacterial killing of neutrophils and macrophages, as well as lymphocyte proliferation and differentiation, production of antibodies by B cells and cytotoxic activity of NK cells. On the other hand, vitamin D regulates a number of important functions within the host. It maintains epithelial homeostasis and absorption of phosphate and calcium in the intestine, and helps in the development and proper functioning of the immune system. Vitamin E enhances lymphocyte proliferation, NK cell-dependent cytotoxicity, Th1 responses, antibody production, and secretion of cytokines and also enhances the antibacterial activity of neutrophils and inhibits oxidative damage and apoptosis in macrophages.
In a study, ginkgolic acids have been reported to treat acute infections caused by a number of viruses, including CoVs, EBOV, ZIKV, IAV, measles, HSV-1, HSV-2 and varicella-zoster virus. Several herbs and traditional medicines (e.g., ginseng, gingko biloba), flavonoids, and other nutrients (magnesium, zinc, carnitine, omega-3 fatty acids) as well as vitamins (e.g., B2, B3, B6, B9, C, D, E) have been reported to treat brain injury. Wheeler et al.demonstrated that healthy microglia are required for the protection against lethal CoV encephalitis in mice.
The human receptor angiotensin converting enzyme 2 receptor (ACE2R), a transmembrane protein, serves as the main entry point into cells for nCoV-19.Therefore, ACE inhibitors and angiotensin receptor blockers (ARBs) that are used to treat high blood pressure may upregulate ACE2R expression, hence may affect the severity of nCoV infection. ACE2R overexpression reduces oxidative stress and cyclooxygenase (COX)-mediated inflammation, which might be helpful for nCoV-19’s existance and replication in the host cells. However, high glucose diet can activate ACE2R in human.
In summary, diets containing natural antioxidants and vitamins may be helpful to fight against viral infections, including the nCoV-19. These types of components can stimulate and strengthen our immune system that may help us to act directly against nCoV-19 infection. Moreover, by this way sufficiently produced antibody may act against nCoV-19.
(Dr. Muhammad Torequl Islam, Assistant Professor, Department of Pharmacy, Life Science Faculty, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj; e-mail:[email protected])
