Can You 'Boost' Your Immune System To Protect Against COVID-19?

By The Wild Women On Top Team

Since COVID-19 (coronavirus) began to spread, many of us have been thinking about how we can best protect ourselves and our loved ones from getting sick. The internet is full of 'immune-boosting' recipes, supplements and superfoods... but do any of them actually work? 

The short answer is... it depends. 

Our immune system helps us fight infection in the body and works to protect us against damaging foreign pathogens and diseases. We want to support our immune system so when it’s confronted by an incoming virus or bug it has the appropriate response, not an exaggerated response. 

Our health experts are clear that the best way to combat this virus is to avoid human contact by practicing social distancing, practicing good hygiene (such as coughing into your elbow or a tissue and washing your hands regularly) and staying home unless it's for an essential reason.

However, there are some other things we can all do to keep healthy and support our immune system. 

We've asked the experts and here are the answers.

Can We Actually 'Boost' Our Immunity?

We commonly hear the phase 'immune-boosting', but can you actually 'boost' your immune system to prevent infection?

Clinical immunologist Dr Ana Dosen says you can't "boost" your immune system, but you can enhance the body's ability to achieve the "appropriate immune response" - especially through diet. She says you don't want to have an underactive immune system, but you also don't want to have an overactive immune system. If the immune system is working overtime, it can potentially harm healthy cells... so the idea of "boosting" it is actually counterintuitive. 

But there are ways we can support our immune system and help it to function properly, to give ourselves a better chance at combatting illness. 

"The best way to [support immune function] is to eat well," Dr Dosen says.

"That's the only way we can do it in a sustained fashion. We know there are lots of important cells in our intestine that can regulate our immune system. If we eat a healthy diet, which has a diversity of fruits, vegetables and protein, then we encourage the good growth of these healthy bacteria which we call the human microbiome."

What Should We Be Eating To Support Our Immune System?

Over 70% of our immune system is centered in the gut - where the body breaks down food and aborbs important nutrients. The microbiome (a community of micro-organisms that live within the body) and the immune system are closely involved with each other. A “strong, varied microbiome” is beneficial in fighting incoming nasties.

So, how do we improve our microbiome and keep our gut nice and healthy?

Nutrition scientist, dietitian, author and presenter Dr Joanna McMillan says that’s where a plant-rich diet is super important. She says to help fuel lots of different bugs in your gut, you need lots of different fuel sources. 

“That’s where that diversity of plant foods comes in. The key word is diversity. What’s important is the plants you’re including [in your diet]. I tend to separate them into wholegrains, legumes, fruit and vegetables, and nuts and seeds. If you get those four different groups, and a variety of each, and the right quantities, you’re going to help yourself have an even and diverse microbiome.”

Foods like ginger, lemon, garlic and turmeric are also great for supporting immunity. They're nutrient-dense and full of goodies that the immune system needs.

"They all contain nutrients or phytochemicals that have anti-inflammatory, antibacterial or anti-viral effects or, as with lemon, contain a nutrient the immune system needs (vitamin C in this case). So while they won’t be miracle cures or keep infection away, they certainly can support immunity and good health," Dr McMillan says.

Is There Anything We Shouldn't Be Eating?

There are some foods that aren’t good for the microbiome, according to Dr McMillan.

“The things we know that are bad for the microbiome include too much saturated fat, too many highly processed foods, and too much protein - especially from animal sources. It doesn’t mean meat is bad but it’s all about quantity and balance with your plant foods. Things like emulsifiers and artificial sweeteners are also bad for the microbiome.

"Obviously if you have them once in a while, it’s not going to have too much impact but if you’re having them too often, it’s likely to be pushing out the foods that are really good for the microbiome.”

Can Exercise Affect Our Immunity?

We know exercise has incredible benefits for our mental and physical health. Regular physical activity helps reduce the risk of chronic diseases, lower blood pressure, reduce stress levels, improve cognition and improve sleep. But regular aerobic exercise, such as walking, has also been shown to benefit immune function. While more research is needed in the area, studies have indicated exercise can benefit immune functionspecifically following vaccination.

But research also suggests exercise intensity can have an impact – with moderate, regular exercise being more beneficial than high-intensity, prolonged activity, when it comes to immune function.

Dr Dosen says exercise such as walking is good for immune function because it ensures your metabolism is working efficiently. She says overexercise, or exercising at high intensities when you're not used to it - isn't a good idea. 

"For people who haven’t done a lot of exercise, and you put your heart rate up too high... it can stress your general metabolism. When you overexercise, or you are too fierce with your exercise, you end up stressing your immune system."

Research suggests moderate exericse, such as walking, 3-5 times a week for 45 - 60 minutes can have "immune-protective benefits". So, not only is walking great at warding off chronic disease, reducing blood pressure, boosting mood and reducing stress - it can also benefit your immune system! 

We Know Nature Is Amazing, But Does It Impact Our Immune System?

Being immersed in nature also has a range of incredible benefits for your mental and physical wellbeing. Walking in nature makes you happier, reduces brooding, improves circulation, lowers your risk of chronic diseases such as diabetes and has even been shown to change the brain. It's good for your body, mind and soul.

But being immersed in natural environments has also been shown to impact immunity. Studies revealed that a two-hour walk in nature has the affect of increasing the number of anti-cancer NK (natural killer) cells by up to 50%. Another study in Japan had similar results, finding that being immersed in forest environments had the affect of increading the number of NK cells.

One researcher notes that being exposed to nature switches our body out of 'fight or flight' mode into 'rest and digest' mode, which allows the body to devote more attention to buidling important resources like the immune system. 

Going for a walk in nature is the perfect tonic for a healthy, happy life. So don't forget to get your shoes on every day and get outside to experience the mind-blowing benefits of nature.

Do I Need Fancy Supplements?

Vitamins and minerals are critical for the proper functioning of the immune system, but you can have too much of a good thing. Research shows excessive amounts of nutrients can actually negatively impact immune function. So don’t go reaching for those fancy, expensive supplements (unless you’re directed to by a healthcare professional). Dr McMillan says if you’re meeting your daily nutritional requirements, which is relatively easy to do with whole foods, then you shouldn’t need to take supplements.

“Overdosing or mega-dosing - particularly of minerals or fat-soluble vitamins - is actually quite detrimental because minerals will compete with each other. If you start taking a big supplement thinking it’s going to be really good for your immune system, actually what you can be doing is duping your absorption of iron, or copper, or other minerals which play an important role. So, it upsets your natural balance of nutrients. Your body is much more adapt at dealing with the natural nutrient matrix that you find in whole foods, compared to swamping your system with supplements.

"Most of us are dealing with a drop in our income right now, and the last thing I want is for people to think they have to spend a lot of money on supplements, when actually, they can just focus on getting their nutrients from good whole foods.” 

However, Dr McMillan says that we may need to consider our vitamin D intake, as many of us are spending more time indoors and not getting as much sun. To increase your vitamin D intake, she says eggs are a great source. But going for a walk during the day or sitting outside for 20 minutes at lunchtime is also a great way to get your daily dose of vitamin D.

So what are the key takeaways?

  • We can support our immune system, but we can't, and don't want to, "boost" it.
  • We can support our immune system and gut health by eating a plant-rich diet and a diversity of whole foods.
  • If you're meeting your daily nutritional requirements, you shouldn't need to take supplements.
  • Exercise can benefit immune function - especially moderate, regular aerobic exercise - so keep walking! 
  • Exposure to nature has been shown to benefit immunity.

You can find out more about healthy eating on Dr Joanna McMillian's website here.

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