Winter immunity: How to stay healthy with natural foods

Winter immunity: How to stay healthy with natural foods

Team ErbologyErbology

The nights are drawing in, and the air is getting crisper. Soon, the leaves will start to turn the color of rust, and we’ll retreat indoors to hibernate by the fire with a mug of something warming. There is certainly plenty to love about the move into fall and winter, but the colder seasons can leave you feeling run down. We take a look at the best advice for how to stay healthy in winter.

December 09, 2020 5:22 pm


Fall and winter can be a testing time for our immune systems. Along with having to contend with colder temperatures, rain and snow, we are also exposed to the many illnesses which flourish during the cooler seasons.

Bad weather in itself is not to blame for the added pressure on our immune systems around this time of year, but rather the way we tend to live during the colder months.

Luckily, there are a few simple changes you can make to get your immune system in the best possible shape for the winter ahead.

To understand how we can help our bodies defend themselves against winter bugs, first let’s take a look at what your immune system is, and how it works.

What is the immune system?

Put simply, your immune system is the organs and methods your body uses to either keep bugs out of your system, or destroy them if they manage to make their way inside.

The organs that keep bugs out of the body are called ‘barrier organs’. These include your skin, mucous membranes and the acid in your stomach. Their job is simple: don’t let any bugs make it past their defences into your body.

Unfortunately, some bugs do succeed in getting around them. Bugs can enter your body through a wound in your skin, for example, or if you consume a bug that can survive the harsh environment of your stomach acid.

Luckily, your body is ready to mop up any invaders.

Other organs in your immune system, called the ‘lymphoid organs’ or ‘lymphatic system’, attack and kill any bugs that make past your barrier organs. The lymphatic system makes use of a range of different methods to first find the invading bug and then to destroy it. Your bone marrow, lymph nodes and spleen are just a few key parts of your lymphatic system.

Keeping healthy in winter

Types of pathogens

So what are these organs defending you against?

There are few different types of bugs that can cause problems in the body. Any organism that causes disease is called a ‘pathogen’. You will have heard of the most famous types: bacteria and viruses.

Bacteria are single-celled organisms which can have a spherical, spiral, or rod-like shape. Many of them are perfectly harmless, or even good for us, but a few have the ability to cause disease. Usually, they’re slightly bigger than viruses, but they’re still much too small to be visible to the human eye. Disease caused by bacteria can include strep throat and urinary tract infections.(1)

Viruses – which, thanks to recent global events, we’re all very familiar with – are different in that they need a host to survive and spread around.(1)

Disease-causing viruses inject themselves into your cells and take them over. They effectively hijack the cell and change its function in order to produce lots of copies of themselves. The cell then dies, and the new viruses spread. Viruses cause diseases such as HIV and respiratory illnesses like flu and, unfortunately, coronavirus.

There are also some other, less well-known pathogens: fungi and parasites. Yeast and mould are examples of fungi which can cause disease in humans. Usually, though, they’re less able to make trouble in the body than bacteria and viruses.

In fact, fungal infections are generally only a threat to a person’s life if their immune system is already compromised, for example through chemotherapy.(1)

The final group of major pathogens is made up of parasites such as worms (like tapeworm) or protozoa. These single-celled organisms can also cause disease; Malaria, for example, is caused by a protozoa called Plasmodia.

Given the variety of threats, your body needs a variety of different tactics to make sure you stay healthy.

White blood cells and the immune system

Think of white blood cells (leukocytes) as the soldiers of your immune system.

There are a couple of different types: phagocytes and lymphocytes.

Phagocytes get rid of pathogens by effectively gobbling them up. The phagocyte approaches a pathogen and moves around it until it is fully surrounded, before absorbing the pathogen into itself, where it can be broken down and destroyed.

Lymphocytes destroy pathogens too, but importantly, they can help you body remember them. This means your immune system can react faster to destroy them if they appear again. In the future, your body will be able to neutralize the recognized pathogen before it can cause disease. This is why you can remain immune to some diseases after having been infected in the past.

There are two types of lymphocytes.

B-lymphocyte cells act as sentries, keeping an eye out for any cells that shouldn’t be there. They can’t destroy a pathogen on their own, but if they find one, they send out antibodies which stick to the pathogen and raise the alarm to other cells. Once released, antibodies stay in your bloodstream, ready to react quickly if the pathogen should return.

T-lymphocytes are sometimes called ‘killer cells’ because their job is to track down the foreign cells which the B-lymphocytes have marked, and destroy them.

Cold weather, in itself, doesn’t make your immune system weaker or stronger than it would otherwise be. However, the winter period makes it easier for illnesses to be spread because often we’re sheltering indoors, in close contact with other people who might be carrying the pathogen.

Why winter takes a toll on your immune system

The main factors that can weaken your immune system are age, stress, and eating a poor diet.

Cold weather, in itself, doesn’t make your immune system weaker or stronger than it would otherwise be.

However, the winter period makes it easier for illnesses to be spread because often we’re sheltering indoors, in close contact with other people who might be carrying the pathogen.

There’s also evidence that sunlight is effective at killing off viruses out in the open.(1) Less sunlight in winter means that more viruses are able to survive long enough to latch onto a new host.

So, while the winter season sees many animals preparing their burrows and nests for the toughest time of year, for pathogens, life is about to become much easier.


sea buckthorn shot

Eating for immunity: vitamins and minerals

While your immune system is very effective at protecting you from disease, there are a few things you can do to lend a hand. These involve making little changes to your diet, to give the organs involved in protecting you from pathogens everything they need to function healthily.

There are three main groups of foods that you should consider when eating to support immunity. The first is vitamins and minerals. Below are the key micronutrients involved in immunity:

  • Vitamin C is a powerful antioxidant, which helps to reduce oxidative damage in the body. But it also plays a crucial role in phagocytosis, the process by which your phagocytes gobble up intruding pathogens.(2) Find it in fruits and vegetables, particularly citrus like bergamot and orange. Or, for a big hit of vitamin C, try sea buckthorn juice. One sea buckthorn berry contains twelve times the vitamin C of an orange!
  • Vitamin D is also important for immunity, and deficiency in this vitamin can lead to an increased susceptibility to infection.(3) Stock up by eating hemp seed, tofu and mushrooms. For bonus vitamin D, leave your mushrooms in the sun before you eat them – like us, they’re able to soak up vitamin D from sunlight.
  • Zinc, selenium and iron are important minerals involved in your immune response. Deficiency in zinc can reduce the efficiency of phagocytosis, while iron regulates the function of your T-lymphocytes, the ‘killer cells’ that find and destroy pathogens(4). Selenium is also an antioxidant and a deficiency can slow your immune response down, giving pathogens more of a chance to do damage in your cells.(5) Almonds, walnuts and lentils are a great source of zinc, while Brazil nuts pack the highest amount of selenium of any plant source. Iron can be found in dried apricots, spinach, and pumpkin seeds.

Foods for gut health

Given that your digestive system is one of the best ways for foreign bacteria to get into your body, it shouldn’t come as a surprise that more than half the antibody-producing cells in your body reside in your gut. That means it’s incredibly important to look after your gut if you want to keep your immune system healthy.

When it comes to gut health, not all bacteria are bad. Quite the opposite!

There are 100 trillion bacteria living in your gut.(5) Some are beneficial, some less so, but they exist in a delicate balance that keeps you healthy.

If you’re eating for immunity, you want to feed and look after your ‘good’ bacteria, which will naturally keep any ‘bad’ bacteria under control.

There are two types of foods that can help you do this: probiotics and prebiotics.

What are probiotics and prebiotics?

Probiotics are foods which contain live ‘good’ bacteria. The intention is that when you eat them, these extra bacteria reach your gut and boost the numbers of ‘good’ bacteria in your system, contributing to better gut health. Live yoghurt is a popular example of a probiotic.

However, there is some debate about whether the extra bacteria survive long enough in your digestive system to be useful.(7). Generally speaking, if you enjoy eating probiotics like live yoghurt and kimchi, you should keep them in your diet as they may have a positive effect on your gut health.

Prebiotics, on the other hand, are foods which you can’t digest yourself, but which provide a hearty meal for your gut bacteria. To be a prebiotic, foods have to meet three criteria:

  1. They have to be able to stay in tact until they reach your gut bacteria. That means they can pass through your stomach acid, and that you can’t digest or absorb them yourself.
  2. Your gut bacteria have to be able to ferment them.
  3. They have to stimulate or grow your gut bacteria, with a positive effect on your overall health.(8)

There are a few different types of prebiotic fibre which you should look out for: fructo-oligosaccharides (FOS) or fructans, and galacto-oligosaccharides (GOS). Unpronounceable names aside, both make great additions to your diet, and both can be found in high levels in one plant: Jerusalem artichoke. Up to a whopping 50% of our Organic Jerusalem Artichoke Powder is made up of inulin fibre, which is a type of fructan.(8)

Other good prebiotic foods include asparagus and leeks, which contain FOS, and chickpeas and lentils, which contain GOS.


The final group of immunity-boosting foods is adaptogens.

Adaptogens are foods which have a regulating effect on your body, meaning they can ‘adapt’ to whatever your body needs. For example, if you’re feeling tired and sluggish, adaptogens can help to energize you, but if you’re feeling jittery, they can help to relax you. Pretty impressive for a single plant!

You can find out all about the types of adaptogens and their benefits in our article ‘What are adaptogens?’, but here we’ll just focus on their ability to boost your immune system.

One thing adaptogens are particularly good at is regulating stress. As we mentioned above, stress is a major factor that can weaken your immune system.

When your body reacts to stress, it goes through a few different stages. First, you’ll go through an ‘alarm’ phase, when your body kicks into high gear to deal with the stressor. This is when your ‘fight or flight’ response would be activated. Imagine getting a bit of unexpected news which sets your heart rate racing.

Next, you’ll go through a resistance phase. This is when your body is dealing with the problem. You’ll feel more alert than normal and your body will still be experiencing the signs of stress.

Finally, you will wear yourself out, and experience exhaustion. Your body will take a short time to come back to the level of wellbeing where you were before you received the unexpected news.

However, adaptogens can help by softening the effects of stress. Instead of launching a dramatic ‘fight or flight’ response, your body will respond more gently, and the resistance phase (when you’re dealing with the stressor) will last for longer.

Best of all, there’s no dramatic exhaustion phase. Instead, your body slowly comes down from the stress response, leaving you operating at a slightly higher level of heterostasis than before. This is called ‘adaptation’, and means you’re better able to respond to stressors in the future.(9)


Aloe vera juice

Which foods are adaptogens?

You’ll already be familiar with some adaptogens, while others sound a bit more exotic.

Familiar faces include aloe vera, matcha green tea and ginger.

The most common adaptogens fall into two families: mushrooms and herbs. But these aren’t the usual kitchen ingredients you can find at a supermarket.

In the mushroom family, adaptogens include reishi, cordyceps and lion’s mane varieties. You can eat them fresh and whole, but if you’re planning to include adaptogen mushrooms in your diet regularly, it might be more convenient to choose a powdered version. It’ll keep for longer in your cupboard, and is very easy to mix into soups, smoothies and stews.

In the herb family, look out for milk thistle, ashwagandha and Panax ginseng, a particular variety of ginseng.

These adaptogen herbs are traditionally taken in teas, but it can be difficult to get hold of the fresh herb. Powdered forms, such as our Organic Milk Thistle Powder, are an easy way to add them to your diet and mix happily into lots of sweet and savoury dishes.

Your winter immunity diet

We’ve covered a lot of ground, so let’s wrap up with a simple summary of the best foods to keep healthy in winter.

Firstly, make sure you’re getting your vitamins and minerals with lots of fruit and vegetables, particularly sea buckthorn, fresh berries, mushrooms, spinach, nuts and seeds.

Next, give your gut a helping hand with lots of prebiotic fibre, found in Jerusalem artichoke, leeks, asparagus, chickpeas and chicory.

Finally, introduce some adaptogens into your diet to help you manage stress, such as aloe vera, milk thistle, ashwagandha or an adaptogen mushroom such as reishi, turkey tail or cordyceps.

With a scientifically-backed diet behind you, you’ll be in the best position to head into winter feeling great.

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