The Food and Immune System Connection

Amanda Hunter

Amanda Hunter

Have you ever considered the connection between the food we eat and the impact on our immune system? It may sound like a pretty odd connection but let me assure you there is a direct correlation between the two.
You may have heard the old saying – you are what you eat – but never quite understood it…
 
Food molecules operate at the cellular level. There are nutrients and molecules in our food that goes beyond just the calories. The chemicals and molecules in the food we eat travel around our bodies and bathes every cell, influencing how our body will behave.
 
So, let’s take a look at the immune system.
 
Our immune system is mostly made up of cells that defend our body from invaders to protect us and keep us healthy. Invaders come in the form of bacteria, viruses, parasites, spirochetes, yeast and toxins. They all sound like pretty nasty stuff! Funnily enough, the body treats any foreign object entering it as an invader….even food!
 
Thankfully we have two forms of protection from our immune system. The first responder is known as the innate immune system which then triggers the adaptive immune system. I’ll explain these both in a bit of further detail…
 
Our innate immune system is a physical barrier. This is our skin and our mucous membranes which form a tight seal to keep the outside world exactly that – outside of our body! In addition to this, we have our intestinal lining. When you think about it, we’re taking in the outside world with every single bite of food so our intestinal lining becomes an extremely important barrier!
 
Essentially it is this innate immune system that decides what should come into or stay out of our system.
 
We then move onto the second line of our immune defence, which is the adaptive immune system. Now, this system takes time to respond (sometimes hours or even days) and the most interesting part is that it has a memory! This is great when it comes to fighting those nasties but not so great for people who have food sensitivities. I’ll come that that later.
 
The adaptive immune system contains B cells (B lymphocytes) which are the antibody-producing cells; and T cells (T lymphocytes) which create inflammation. Inflammation can be a positive thing when defending the body. It is essentially a release of chemical and proteins from the immune system and other cells which attack the foreigner, however, it can also irritate and cause damage to the surrounding tissue. Inflammation is supposed to ‘turn on’ to defend the body and then ‘turn off’ again once the danger is over.
 
The problem arises when the inflammation signal ‘stays on’. This results in chronic inflammation which affects every cell in the body. It could be felt locally in the muscles or joints; or it could be systemic inflammation which non-specific and causes brain fog, fatigue and a general feeling of puffiness.
 
A little side note here – it is even possible for fat cells to have inflammation! Which then makes it very difficult for a person to lose weight.
So, the big question then… how does food impact our immune system?
 
Food acts as information for the immune system! Recall, how our immune system is predominantly made of cells? Food molecules operate at the cellular level – they bind to the cells and change how it functions.
 
Simply put…. healthy food = healthy genes.
 
Unhealthy food = …. well, you can guess….
When we eat plant nutrients (known as phytonutrients), they travel into the nucleus of the cells and actually change the expression of your genes! If you wanted to take a deeper dive into this, nutrigenomics is the study of how nutrition affects the genetic expression of our cells and how this can be used in disease prevention and treatment. It’s such an interesting emerging area of research!
 
I want to focus more around how food can cause inflammation within the body. There are so many people affected by the general ill-feelings I mentioned above, yet we don’t realise it is caused by inflammation. Which means it is something that we can work on to eliminate!
 
The best thing we can do we eat foods which are nutrient-dense to keep our immune system in good balance. Nutrients effect our immune function!
 
They affect us through our genetics; our environment (toxins and inflammatory foods); and nutrient deficiencies such as Vitamin A & D or fatty acids.
 
A few simple tips to optimise immune function and reduce inflammation in our bodies:
  1. Choose wholefoods. These are foods which are minimally processed and closely resemble how they appears in nature.
  2. Eliminate sugar as this stimulates immune cells to release inflammation molecules within the body. Even foods which on face value don’t appear to contain sugar can have a high glycemic index (GI). High GI foods are treated the same as sugar within the body and cause inflammation.
  3. Know your fats! Trans-fats and saturated fats are inflammatory within the body. Omega 3 and 6 fats, however, have anti-inflammatory properties. It is important we understand how our food is created. For example, knowing the difference between grass and grain-fed beef. Grass-fed cattle create healthy fats including omegas. Grain-fed cattle, on the other hand, are fed a diet of corn and soy which create bad fats within their bodies which ultimately ends up in our diets.
  4. Include antioxidant-rich foods into our diets. Your immune cells are constantly exposed to toxins, chemicals and microbes. We need a constant supply of antioxidants to roam around inside our bodies ‘mopping up’ free radicals which are damaging our cells. Foods rich in antioxidants are berries, orange, kale, capsicum, sweet potato, mango, kiwi, broccoli, spinach, nuts and sunflower seeds to name a few!
Our immune system does a pretty great job at protecting our body, however, for some people it can lead to them developing sensitivity around certain foods.
 
I’m not talking food allergies which have very specific reactions (difficulty swallowing, hives and potentially anaphylaxis) and can be tested for; I’m referring to a food sensitivity. A sensitivity can be difficult to diagnose due to numerous possible reactions and is often best explained as ‘you feel better when you don’t eat it, and worse when you do’. Symptoms of food sensitivity may be gut-related such as gas, bloating, constipation or diarrhoea; or they may be the systemic symptoms mentioned earlier such as puffiness, brain fog, fatigue, skin rashes or headaches.
 
The easiest way to understand a food sensitivity is to imagine that every piece of food we eat contains a label or ‘name tag’. Our immune cells are able to recognise whether cells in the body are its own self or foreign by reading the ‘name tag’. When the immune system identifies as ‘name tag’ as its own self, it will leave that cell alone and not attack. If identified as foreign, the immune system will attack the cell.
 
Our digestive system is designed to destroy the ‘name tag’ on food when eaten. In a healthy gut, the food is completely digested in the stomach, destroying the ‘name tag’. The food becomes unrecognisable to the immune system and therefore continues on it’s journey, destroyed by enzymes and stomach acid. Where the intestinal lining and barrier and healthy, the immune cells inside the body are not exposed to the ‘name tags’ on food and so there is a low risk of developing a food sensitivity.
 
Now take an unhealthy gut with a weak intestinal lining. Where the cells lining the gut should be tightly connected, the ‘glue’ holding the cells together is destroyed and spaces open up between them (aka ‘leaky gut’). Large pieces of food, microbes and toxins are released and enter the body. The immune system identifies the ‘name tags’ on these as foreign invaders, reacts and attacks them. This is how a food sensitivity can come about. And recall, when I mentioned that the immune system has a memory? It can actually remember which foods led to such a reaction and act the same way the next time they are eaten.
 
The best way to test for food sensitivities is through an elimination diet where the top 5 potential contributors (gluten, dairy, soy, corn and eggs) are removed from the diet for 3 weeks before slowly being reintroduced one at a time every 2-3 days. If a food sensitivity is prevalent, an immediate reaction will occur. Once a particular food is identified as causing the sensitivity, it must be removed from the diet for anywhere between 6 months and 2 years to allow sufficient time for the immune systems to ‘forget’ about that food.
 
What can we do to restore our intestinal lining?
 
The good news is there are certain foods we can start to incorporate into our diets to help restore our gut flora and heal our intestinal lining!
  • Cultured foods (such as yogurt and kefir) with live active cultures
  • Fermented foods such as kimchi and sauerkraut
  • Prebiotics founds in vegetables such as onions, garlic, leeks, rye, blueberries and bananas
  • Ghee and coconut oil
  • Glutamine which can be found in animal proteins, beans, cabbage, beets, spinach and parsley
 
So, what can we take away from all of this?
 
Food is so much more than just something to fill our bellies. It can heal us or make us sick, and it affects us down at a cellular level. A healthy gut is also imperative to good health!
 
I know how I want to feel and what I’m going to do about it.
 
How about you?

Amanda xx

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