The novel coronavirus has caused infection to over millions of individuals and more than thousands of deaths in hundreds of countries across the world. Unfortunately, there is no single vaccine and specific treatment(s) for it. Protective measures like isolation, quarantine, social distancing, avoidance of large gatherings, frequent hand-washing etc. have been suggested by the public health experts. However, along with the protection and treatment strategies, dietary supplements and nutritional behaviour may help us to manage the novel coronavirus infection in humans.
Natural antioxidants such as quercetin and alliin are evident to increase the presence of Firmicutes genera, while a decrease in Bacteroidetes and Proteobacteria in the intestine, therefore, reduces the incidence of inflammatory bowel disease. Diets containing a high amount of unsaturated fatty acids, omega-3 and omega-6 fatty acids found in large quantities 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 fibre have profound effects on the regulation of our immune system.
Food supplements may be a potential source to manage the infection of the novel coronavirus. In a study, feed additives such as phosphoric acid, citric acid, or fumaric acid were found to reduce porcine delta coronavirus in infected pigs. In another study, chick embryo tracheal organ cultures showed increased resistance to infection by a coronavirus after exposure to ascorbate (also called vitamin C). The vitamins of the B group play important roles in immune system homeostasis and functions. Thiamine (vitamin B1) promotes the accumulation of naive B cells in intestinal Peyer's patches and induces immunoglobulin A (IgA) production in the intestinal mucosa. Niacin (vitamin B3) has anti-inflammatory properties. Pyridoxal phosphate (vitamin B6) has anti-inflammatory and antioxidant effects.
Vitamin C is evident to manage common cold in experimental animals. The deficiency of this vitamin causes immune system dysfunction and increased susceptibility to infections. On the other hand, vitamin D regulates several 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 antibody production, secretion of cytokines and also enhances the antibacterial activity of neutrophils and inhibits oxidative damage.
The human angiotensin-converting enzyme 2 (ACE2) receptor serves as the main entry point into cells for the novel coronavirus. Therefore, ACE2 inhibitors and angiotensin II receptor blockers (ARBs) that are used to treat high blood pressure may upregulate ACE2 receptor expression, hence may affect the severity of the novel coronavirus infection.
To sum up, diets containing natural antioxidants and vitamins may be helpful to fight against viral infections. These types of components can stimulate and strengthen the immune system that may help us to act directly against the novel coronavirus infection.
The writer is an Assistant Professor of Pharmacy at the Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, Bangladesh.