Immunity is a mainstream health concern thanks to COVID-19
The COVID-19 pandemic has made immunity the hot topic of popular health and wellness culture. Especially in the context of diet and nutrition.
Newspaper columnists and health bloggers extol superfoods that can boost immunity. TV celebrities and social media influencers reveal their immunity-boosting secrets. Supermarket shelves are full of foods that support immune function. And vitamin and mineral supplements claim immune-supporting properties.
In May The Grocer, the food retailers’ trade magazine, reported a spike in sales of immune-supporting supplements. And in June The Financial Times highlighted the global surge in interest in foods and ingredients linked to immunity.
There’s no doubt, promising to improve immunity sells!
Can your diet protect you against Coronavirus?
But are the immunity-enhancing claims used to sell us superfoods and supplements true? And can you ramp up your immunity to protect you from Coronavirus?
The British Dietetics Association gets straight to the point,
no specific food or supplement will prevent you catching COVID-19British Dietetics Association
That’s a pretty definitive “No”.
So, until there is a vaccine, the best way to protect yourself and your loved ones from COVID-19 is to follow the government’s advice. To follow the social distancing, hand washing and mask wearing rules.
But if you are unlucky and catch Coronavirus, you want your immune system to be functioning at its best.
And diet can help with that.
The link between nutrition and immunity
The myth marketers are peddling you is that one magic ingredient will improve your immunity – and by implication protect you against COVID-19.
And like all the best myths, it’s rooted in truth. Diet and immunity are interlinked. A diet deficient in nutrients will compromise your immunity. And in the developing world malnutrition and infection live side by side. But mega-dosing vitamins and minerals on top an otherwise healthy diet doesn’t improve your immunity.
The myth marketers are peddling you is that one magic ingredient will improve your immunity
A varied diet full of all the essential nutrients provides everything your immune system needs to function normally. And you need all the essential nutrients. Yes, there are some specific nutrients relate to immune function, but your immune function doesn’t work in vacuum. It is tightly interlinked with the rest of your body’s metabolism. For your immune system to work at its best you need to feed your whole metabolism.
In a minute, we’ll take a closer look at the nutrients that are specifically linked with immune system function and where you can find them. But first, let’s take a closer look a few misleading claims made by marketers and influencers.
Boosting the immune system
“Boosting” your immune system sounds appealing but is actually meaningless. It’s a marketing phrase with no scientific foundation. Yet it’s such an attractive idea that even mainstream media are treating it seriously.
And even if you could “boost” your immune system would you really want to?
Because if you catch a virus, many of the symptoms you experience are not caused by the virus. They are brought on by your immune system as it battles the invader. For example, the usual symptoms of a common cold like a runny nose, mild fever, aches and pains are triggered by your immune system as it fights the virus.
What’s more, many of the complications of COVID-19 are a result of a disproportionately large immune response to the virus.
So, even if you could, “boosting” your immune function wouldn’t be a good idea. What you want is normally functioning immune system.
So, what about claims that foods support normal immune function?
“Supporting” immune function
There’s a simple reason food manufacturers love to plaster immune-supporting claims on their product labels. Immunity is a hot topic. Promising improved immunity sells.
But in the UK there are strict laws governing the health claims on food labels. To claim food or food component can protect against infection is illegal. Why? Because there’s no scientific proof to back up that kind of promise.
To suggest an individual vitamin or mineral will support immune function is a willfully deceitful oversimplification.
And “supporting” immune function is as close as food marketers can get to claiming immuno-protective properties without breaking the law. It sounds like a real health claim and it sells products. Because who wouldn’t want a magic nutrient to give extra support to their immune system? Especially during a pandemic.
But your immune system is complex, multidimensional. And it’s tightly interwoven with your body’s whole metabolism. Your metabolism needs all the essential nutrients and micronutrients to function properly. And therefore, so does your immune system.
To suggest an individual vitamin or mineral will support immune function is a willfully deceitful oversimplification.
Green tea, ginger, turmeric, goji berries, chia seeds… there’s no shortage of “superfoods”. All of them can be part of a healthy diet. But none of them makes a diet health. No “superfood” has magical immunity-boosting properties.
Marketers will point to studies demonstrating the benefit of their active ingredient. But here’s what they’re not telling you.
- The dose of the active ingredient in the study was much higher than available in the superfood
- The study was done in animals or in test tubes, not human beings
- They’re interpreting the results in a far more positive light than the researchers did
- The active ingredient is widely available in other foods.
- All of the above.
No “superfood” has magical immunity-boosting properties
But what about taking a supplement to fill any nutrient gaps in your diet?
Will a multivitamin supplement improve my immunity?
There’s one thing that supplement marketers don’t want you to know – most people don’t need them.
Yes, supplements can treat nutrient deficiencies in the short term. But the cause for the deficiency – be it diet or illness – needs to be addressed in the long term.
Supplements may help an elderly relative who struggles to eat enough to get all the essential nutrients they need. Reduced appetite, altered eating habits and reduced absorption are all part of the normal ageing process. Absolutely, a multivitamin is a sensible option.
But if you’re healthy and you eat a varied and balanced diet you will get all the nutrients you need for health and proper immune function. (Vitamin D is the exception if you live in Scotland – see below).
And you can have too much of a good thing. Some vitamins and minerals are harmful and can damage your health if you overdo them. And there’s no added benefit to taking more of the safe ones. But it will hurt your wallet.
The best diet for immune function
Now you know a high intake of an individual nutrient can’t improve your immunity. And that a diet missing any essential nutrient it could compromise your immunity. So what is the best diet for your immune system?
To support your immune function you should eat a diverse range of nutrient-rich whole foods from all the different food groups. It’s the best way to prepare your immune system to fight any infection, including Coronavirus.
To support your immune function you should eat a diverse range of nutrient-rich whole foods from all the different food groups
In the UK food is plentiful. But it’s easy to be overfed yet undernourished. Our lives are busy and convenience is appealing. Grocery shelves are filled with ready-made high-calorie foods empty of essential nutrients. But a habit of convenient empty calories will compromise your immune system.
And a repetitive diet full of empty calories can’t be fixed with supplements or superfoods. You’ll still miss out on fibre, antioxidants and other anti-inflammatory phytonutrients that come with whole foods. A healthy diet is much more than the sum of its parts.
The best “immune-boosting”/”immune supporting”/”superfood” diet is a diverse range of nutrient-rich whole foods from all the different food groups. There are too many nutrients essential to the immune system for any other solution.
14 Nutrients that are essential to your immune system
Your body needs protein to produce the immune cells and antibodies that fight infection. And it’s vital to repair body tissues damaged by an infection. That said, most people in the UK have plenty of protein in their diet.
Good sources are; meat, fish, eggs, nuts, whole grains, pulses and beans.
Omega-3 fats are anti-inflammatory and help control your immune response. And two omega-3s are essential, meaning your body can’t make them from other fats.
The best sources are oily fish like salmon, mackerel and sardines. Eating oily fish twice a week provides enough of both essential omega-3s.
Omega-3 is also found in plant foods like nuts and seeds. But it’s a different type of omega-3 which your body must convert it before it can be used. And it’s not an efficient process. Your body requires far greater quantities of plant omega-3 to produce enough of the two essential omega-3 fats.
Gut microbes and gut health have become hot topics in nutrition research. And we’re still learning. But we do know a huge proportion of your immune system is actually in your gut.
Eating plenty of diverse sources of fibre feeds the good bacteria in your gut. In turn, they will help shape and regulate your immune system.
Good sources are; vegetables, fruits, whole grains, nuts, seeds, pulses and beans.
Vitamin A helps maintain the integrity of mucus cells in tissues that stop microbes entering your body (e.g. skin, gut lining). It’s also important in normal immune cell function and antibody response to infection.
Good sources are; liver, carrots, red peppers, sweet potatoes and butternut squash.
Vitamin C supports immune cell function. And its antioxidant properties protect against the damage caused when immune cells kill invading pathogens.
Good sources are; fruits and vegetables, especially oranges, peppers, broccoli, kale, kiwi fruit and strawberries.
Mega-dosing with vitamin C to treat colds and other respiratory infections is popular. But the science is too weak to recommend more than the normal healthy intake.
Vitamin D, the “sunshine vitamin”, is actually a hormone. And it underpins the immune systems ability to fight infection, manage inflammation and maintain gut health.
Your body’s primary source of vitamin D is in-house production when your skin is exposed to sunlight.
many Scots are deficient in vitamin D
But in Scotland and other temperate climates winter sunlight isn’t strong enough for vitamin D production. And even in summer, depending on your lifestyle, it isn’t always possible to get enough sun exposure. As a result, many Scots are deficient in vitamin D.
Diet is not a great source of vitamin D. And your diet only tops up the in-house vitamin D production. Still, the best dietary sources are oily fish and vitamin D fortified foods.
Exposure to enough sunlight is the best natural source of vitamin D.
If you live in Scotland you should take a daily vitamin D supplement from October to April. And even throughout the summer months if you don’t get outside much. The NHS recommends 10 micrograms of vitamin D a day.
Vitamin E has a critical role in immune cell regulation and antibody production. It’s also a powerful antioxidant.
Good sources are; nuts, seeds, whole grains, milk and most vegetables and fruits especially avocadoes.
Vitmin B6 helps regulate inflammation has a role immune cell and antibody production.
Good sources are; beef, poultry, eggs, oats, milk, bananas, potatoes and sweet potatoes.
Vitamin B12’s most important role is in DNA synthesis during cell reproduction. Without it immune cells can’t rapidly reproduce to fight infection. It’s also involved in immune system regulation and the function of some immune cells.
Good sources include; offal (liver, kidneys etc), oily fish, beef, dairy products and fortified cereals.
B12 is almost exclusively found in animal products. Vitamin B12 is found in some plant foods. But it’s not in a form available to your body. Vegans need to supplement and vegetarians should consider supplementing with vitamin B12.
The roles of folate and vitamin B12 are closely interlinked and the symptoms of folate defficiency may be the result of a B12 deficiency. Folate supports immune cell reponse to infection and antibody production.
Good sources are; leafy greens including broccoli and Brussel sprouts, liver, pulses and beans, bananas, avocadoes and fortified breakfast cereals.
Zinc is essential for the rapildy reproducing cells of your body like skin and immune cells. And it’s an antioxidant and protects cells from free radical damage.
Good sources are; meat, shellfish, legumes (lentils, chickpeas etc), nuts, seeds, dairy products and whole grains.
A selenium deficiency lowers your immune cells ability to fight infection.
Top sources are; seafood, offal (liver and kidneys), brazil nuts, salmon, tuna and lentils.
Iron is essential for cell reproduction, including immune cells. And it’s used to produce vital chemical substances your immune system needs to fight infection.
Good sources of iron are; red meat, legumes and pulses, whole grains, seafood, nuts, seeds and green vegetables.
Copper is needed for antibody production. And lack of copper reduces the number of certain immune cells and their ability to fight infection.
Good sources are; liver, leafy greens, nuts and seeds.
That’s fourteen different nutrients that are essential to immune function!
It’s easy to be overwhelmed. Don’t be.
When you look at where to can find the nutrients there’s a lot of repetition. Foods aren’t single nutrients, they’re combinations of nutrients. Eat a variety of whole foods from every food group and you’ll get what you need.
The easiest way to do that is become a Plant Based Omnivore.
Plant Based Omnivore Diet
Humans are omnivores. We evolved to eat plants and animals. The nutrients you need for immunity and health come from both. Plants are a better source of some. Animals are the best source of others.
What is eat a plant based omnivore diet? In descending order of quantity, what you eat should look something like this.
- Lots of vegetables
- Plenty of pulses and beans
- A variety of whole grains
- Some fruit daily
- A few nuts or seeds most days (including 100% nut butters)
- Oily fish at least twice a week (and other fish and seafood regularly)
- Dairy in small amounts
- On days without fish, small quantities of meat including red meat
- The appropriate animal fat or vegetable oil for cooking
- Only a sprinkle of refined and processed foods
- Occasional alcohol? – Why not?
But to be a successful Plant Based Omnivore you need to take control and know what’s in your food. You can’t outsource your diet and health to food manufacturers.
Cook your food from simple ingredients – most of the time.
There’s no diet quick fix or short cut to a healthy immune function. Healthy eating and in turn maintaining your immune system is a life long effort.
When we’re on the other side of the COVID-19 pandemic, you’ll still need a healthy immune system. Your body will always need to protect itself from pathogens and be ready to fight infection.
Until the pandemic is over, and so you’re ready for the one , eat a variety of whole foods from every food group.
Or better yet, feed your body the diet designed for it and look after your immunity and health. Become a Plant Based Omnivore!
Hi, I’m Ralph
I’m an Associate Registered Nutritionist with over 25 years’ experience as a professional chef.
My passion is helping individuals gain control of their diet to achieve food freedom and health in today’s broken nutrition environment.
I’m based in Edinburgh and provide 1-2-1 online nutrition coaching and support across the U.K.