How can I eat better to support my immune system?

During the corona virus pandemic, many people have been interested in the role diet plays in supporting the immune system and combating the disease.

Are there foods that reduce the risk of developing COVID-19? Should I be taking nutritional supplements? Are some foods better for the immune system than others? Does drinking alcohol play a role in lowering the immune response?

Here is your low down on the best way to tackle these questions.

What is the immune system?

The immune system is a complex network of cells and chemical compounds that help defend the body against infections. The gut is the main route of contact between the body and the outside world. Seventy per cent of the body’s immune cells are found along its length and are there to help defend against infections.

Supporting gut health goes hand in hand with supporting a healthy immune system.

Which is best for your immune system - a good diet or single foods?

The best approach to supporting the immune system is eating a diverse, mainly plant based diet and maintaining healthy weight. Plant foods are high in dietary fibre, nutrients and bioactive components that feed healthy gut bacteria which support the immune system.

Diets containing ultra-processed foods (high in fat, sugar and low in fibre), have been shown to reduce healthy bacteria in the gut leading to a weakened immune response to invading bacteria and viruses.

Also, diets based on highly processed foods promote obesity which is a risk factor for developing COVID-19.

There are no single foods which have been shown to have a particular effect against the corona virus.

Healthy gut, healthy immune system

Food, drink, viruses and bacteria all make their way from the outside world along the length of the gut to be digested and processed by the body. It is crucial the gut has the correct balance of healthy bacteria present as they help to maintain the cells that line the gut. If gut health is poor it can become ‘leaky’ allowing bacteria and viruses to enter the body.

Bacteria in a healthy gut also play a role in destroying invading bacteria and viruses.

In addition bacteria in the gut activate vitamins that are important in the immune system such as vitamins A and B12.

Which nutrients are involved in supporting the immune system?
By eating a varied diet you make sure your body receives all the nutrients and biologically important components to support the immune system. Vitamins A, B6, B12, C, D and folic acid all play a role in supporting the cells that make up the immune system. Coloured fruit and vegetables such as carrots, tomatoes, spinach and broccoli, oily fish, eggs, nuts seeds and fortified dairy foods will provide your daily intake of these vitamins.

Micronutrients including copper, iron selenium and zinc which are found in nuts, seeds, wholemeal bread, lean meat, eggs also play a role in maintaining a healthy immune system.

Do I need to take a supplement?

Although vitamin and mineral supplements are flying off the shelves at the moment the only supplement recommended for everyone is a daily supplement of 10 micrograms vitamin D from October to March, and all year round if we aren't often outdoors. This might be particularly important during corona virus lockdowns. Research has shown vitamin D plays an important role in promoting the immune response.

Does drinking alcohol effect the immune system?

The short answer is yes it can. It depends how much you drink and how often. Excessive alcohol consumption (even a single episode of binge drinking) can result in the erosion of the walls of the gut. This damage leads to increased permeability of the gut and a way in for viruses and bacteria to infect the body.

Anything else?

Professor Tim Spector of King's College London recommends: 

"You can also boost your microbiome by adding in fermented foods such as unpasteurised artisan cheeses and natural yoghurt, which both contain live microbes”.

Regular exercise also plays a key role in keeping the immune system functioning.

And finally…..

It is important to note, there are no miracles for preventing or curing COVID-19. The best thing we can all do is follow government advice and avoid exposure to the virus.