New Delhi, Delhi, India.

We have heard of various ways of boosting immunity – in fact it is the buzzword today especially with no defined treatment or vaccine available to fight the disease. We all know that the gold standard for a strong immune system remains a healthy well – balanced diet with immune boosting nutrients, regular physical activity, adequate hydration and good quality sleep for a well-rested mind.

More recently, However, scientific data suggests that improving intestinal health with probiotics could be another effective way of building immunity. The rationale is simple – about 70% of the body’s immunity is found in the intestine which in turn depends on bacteria to shape the immunity. Although this may sound like stuff that Science fiction is made of, our intestine is home to 100 trillion bacteria of 1000 different types which work together to build our immunity. The beneficial ones which are also called probiotics train the immune system, reduce inflammation and ward off harmful disease-causing bacteria and viruses. They also prevent metabolic disorders like obesity by producing metabolites like short chain fatty acids especially butyrate. They also protect the intestinal lining and prevent harmful pathogens and their toxins from entering the blood.

Probiotics are particularly useful in preventing respiratory infections because of their ability to increase activity of Natural Killer cells and levels of antibodies like secretory IgA in the mucosal linings, which are our first line of defence against viral infections.

Given that probiotics shape our immunity, is there enough scientific data that suggests their value in the current COVID-19 pandemic?

A Cochrane review of 12 studies that included 3720 children, adults and elderly suggested that probiotic use may be associated with fewer people suffering from upper respiratory tract infections and lower incidence of the infection. Dr. Irene Lenoir-Wijnkoop, at Utrecht University in Netherlands observed that probiotic use could save health care costs and lost productivity due to acute respiratory tract infections.

The link between the intestine and COVID-19 becomes apparent from the fact that some patients who suffered the infection in China showed symptoms of poor intestinal health and suffered from loss of taste and diarrhoea. This prompted China’s National Health Commission to use probiotics along with conventional treatment in patients with COVID-19 infection for improving the balance of the intestinal flora and preventing secondary bacterial infections.

However, probiotic benefits are strain-specific, and it is important to identify the strain of bacteria that is scientifically proven for the benefit. Some strains of Lactobacillus gasseri, Bifidobacterium longum and Lactobacillus casei strain Shirota have shown to boost immunity and reduce the incidence of upper respiratory tract infections or common cold and flu.

Although we are at a stage where we are still not sure of a clear benefit of probiotics in COVID-19 patients but given the fact that most of our immunity resides in the intestine which is determined by the kind of bacteria present there, it may be worthwhile to ensure a balanced intestinal flora with more beneficial probiotic microbes and a stronger immune system that could help in the fight against COVID-19.