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Covid 19, nutrition and the gut: what you need to know

15 Dec 2020

New evidence highlights a possible link between diet, weight and gut health and risk of Covid-19. More research is needed, but here’s an update so far

Eating healthily can play a role in supporting your immune system. While this alone isn’t enough to stop you catching coronavirus, research is now identifying some of the specific ways in which diet, weight and gut health could play a part in immunity – and your risk of complications from Covid-19.

Here, we summarise the evidence.

Obesity and Covid-19 risk

Almost two-thirds of adults (63%) are overweight or living with obesity in England. In fact, one UK report shows that lockdowns during the pandemic have inadvertently promoted weight gain due to emotional eating, physical inactivity and anxiety.

Another study found that 48% of people reported they’d put on weight during lockdown.

The World Health Organization (WHO) defines overweight as a BMI (body mass index) greater than or equal to 25, and obesity as a BMI greater than or equal to 30.

You may already know that a raised BMI is a major risk factor for cardiovascular disease, diabetes, musculoskeletal disorders and some cancers.

But, now, latest research also shows that carrying excess weight puts you at greater risk of complications from Covid-19, including being admitted into intensive care, with the risk growing substantially as BMI increases.

In a recent meta-analysis it was shown that PLWO (people living with obesity) are at increased risk of:

  • being Covid-19 positive (46%)
  • hospitalisation (113%)
  • intensive care unit admission (74%)
  • mortality (48%).

Nearly 8% of critically ill UK patients with Covid-19 in intensive care units have been morbidly obese, compared with 2.9% of the general population.

There are a number of reasons why obesity could increase the risk of complications from Covid-19. These include increased inflammation, abdominal pressure, worse cardio-respiratory fitness, cardio-renal stress and metabolic dysfunctions.

Obesity also increases the risk of diabetes, cardiovascular disorders, cancers and non-alcoholic fatty liver disease, which all increase the likelihood of severe illness from Covid-19.

Nutrition, diet and immunity

A healthy diet is crucial to keeping your immune system healthy. Our immune system protects us from, and helps us to fight, invading pathogens, including bacteria, fungi and viruses.

Your immune system is always active, but its activity heightens when there’s an infection.

And as we get older, our immune systems become less competent and this is what makes older people more susceptible to infections such as coronavirus.

Research shows that a number of vitamins (A, B6, B12, folate, C, D and E) and trace elements (zinc, copper, selenium, iron) can help to support the immune system, helping to reduce the risk of infection.

One study suggested that zinc may prevent viruses, like the coronavirus, by inhibiting the enzymes they need to spread.

The best way to get the nutrients you need is through your diet. Zinc is found in meat, poultry, cheese, shellfish, nuts, seeds and wholegrains. Selenium is abundant in Brazil nuts, poultry, fish, eggs, nuts, seeds and organ meats such as liver and kidney.

Having said that, there’s no magic bullet when it comes to food and immunity, says Dr Annette Alaeus, Infectious Disease Expert at Livi.

‘More studies are needed on the different vitamins and minerals and their specific importance for the outcome of Covid-19.’

How gut bacteria impacts infections

Your gut is home to trillions of organisms such as bacteria, yeasts, fungi and viruses, known collectively as your ‘microbiome’. This is involved in metabolic, nutritional and immune system functions. So, it’s important to make sure your microbiome is populated with healthy bacteria to keep unhealthy micro-organisms under control.

Factors like poor diet, too much sugar and antibiotics can deplete beneficial bacteria in your gut and this can have an impact on your overall health.

Now, research at Reading University suggests that the gut microbiome may be a harbouring site for Covid-19 and that a person’s microbiome may influence their clinical outcomes.

For example, if ‘good bacteria’ in the gut are low, this can make it more difficult to fight off the virus.

One reason why a healthy microbiome may have an influence on viral transmission and disease progression is that it may help reduce inflammation.

Another theory is that certain types of good bacteria may also alter the virus’s ability to get cellular entry through the gut.

An Italian study found that Covid-19 patients treated with probiotics showed reduced symptoms such as diarrhoea and other symptoms, within 72 hours. There was also reduced admission to ICU and fewer deaths.

Read more about how your gut health affects your immunity.

Vitamin D-deficiency and Covid

Vitamin D is a prohormone produced in the skin during exposure to sunlight. We also get some vitamin D from our diet.

We need vitamin D to absorb calcium and phosphate from our diet and to keep our bones, teeth, muscles and immune system healthy.

Research suggests that around 40% of people are deficient in vitamin D, in Europe, in winter.

Now, researchers are looking at the possible link between vitamin D deficiency and Covid-19.

But according to the National Institute for Health and Care Excellence (NICE) there is ‘no evidence’ that taking supplements can treat or prevent Covid-19. ‘This is extremely important to remember,’ concludes Dr Alaeus.

If you need help with obesity, a Livi doctor can help you in a number of ways including, by referring you to a dietitian or nutritionist and suggesting support groups in your area.

This article has been medically approved by Dr Annette Alaeus, Infectious Diseases Expert, Livi.

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