Microbiome maintenance: Good gut health could tackle COVID-19

A healthy gut microbiome is crucial in mounting a response to the coronavirus, a public health expert says, who also details its role in preventing immune over-reactions that can damage the lungs.

Professor Tim Spector highlights recent research that shows the gut microbiome’s role in the body’s immune response to infection as well as its role in preventing not only damage to lungs but also to other vital organs.

“These excessive immune responses can cause respiratory failure and death,” says professor Spector, who works as a genetic epidemiologist at King's College London.

“This is also why we should talk about “supporting” rather than “boosting” the immune system, as an overactive immune response can be as risky as an underactive one.”

Microbiome & inflammation

Writing in The Conversation, professor Spector says that whilst the finer details of gut microbiome and the immune system interactions are not fully understood, there may be a link between the microbiome makeup and inflammation – one of the immune response’s traits.

He also points out that gut bacteria produce many beneficial chemicals and also activate vitamin A in food, which helps to regulate the immune system.

Here, scientists found that gut microbiome appeared to regulate the host's immune system so that rather than the host's defence system attacking helpful bacteria, the bacteria could co-exist peacefully with the immune system.

The team found the bacteria moderated active vitamin A levels in the intestine, protecting the microbiome from an overactive immune response.

Professor Spector also thinks that rather than take supplements, which claim to “boost your immune system” with no good supporting evidence, the food you eat has a big impact on the range and type of microbes in the gut.

“A diverse microbiome is a healthy microbiome, containing many different species that each play their part in immunity and health,” he adds.

“Microbiome diversity declines as you get older, which may help to explain some of the age-related changes we see in immune responses, so it’s even more necessary to maintain a healthy microbiome throughout life.”

Strengthening immune system

With news that a COVID-19 vaccine is not expected for around a year, people are looking at building up defences from the inside by strengthening the immune system.

Professor Spector writes that the best way to increase microbiome diversity is by eating a wide range of high-fibre plant-based foods, such as those found in a Mediterranean diet.

Also useful is the consumption of natural yoghurt and artisan cheeses, which contain live microbes (probiotics).

Another source of natural probiotics are bacteria and yeast-rich drinks like kefir (fermented milk) or kombucha (fermented tea).

Fermented vegetable-based foods, such as Korean kimchi (and German sauerkraut) are another good option.

“Whether you’re shopping for yourself, your family or for elderly relatives or friends, choosing foods that support a healthy gut microbiome is much more important than stockpiling toilet paper,” says professor Spector.

“Managing your mental health, staying physically active and getting enough sleep will also help to keep your immune system in good shape. And don’t forget to wash your hands!”