Updated: Mar 11
In "The Best Ways to Protect Yourself Against Virus Infections part I" we've seen how much of an impact lifestyle can have on your immune system and making you either more susceptible or more resistant to virus infections.
Diet has a major impact on your immune system as well.
This article will discuss what dietary factors or factors influenced by diet can assist you in building up the best immune system possible, in order to protect yourself from infected bullies, who purposely cough in your face.
In order to understand the importance of the immune system and to understand exactly how it works, or if you simply want to refresh your memory about it, check out part 1 here.
The following topics will be discussed:
Vitamins and Minerals
1. CRUCIFEROUS VEGETABLES
You've been told to eat your vegetables while you were growing up. Your parents told you something along the line:"Vegetables keep you healthy and strong."
Perhaps, you've wondered why and even dared to question your caretakers' or parents' wisdom. More so, if the vegetable in question was one you particularly disliked, such as a vegetable from the cruciferous family. The thought of having to eat it for dinner would give you a day's worth of anxiety. It was worse, if there was no applesauce to mask the taste of this demon's discharge. In that case it could even lead to a sleepless night altogether.
Okay, maybe that was just me.
Thankfully, I've come to love them, although it took a while.
So, how accurate were our parents?
Is there any scientific base to the claim, that they are good for you and keep you healthy and strong?
It appears our parents were all natural born scientists.
Vegetables can indeed keep us healthy and strong.
They can keep you healthy and strong in a variety of ways actually, but this article will focus on the effects they have on our immune system.
These immune cells are important in fending off little critters, that would like to use your intestine as a gateway to host all kinds of illegal activities. These immune cells are basically little policemen patrolling along the lining of your intestines.
If they are lacking, it not only affects your immune system, but it also increases the risk of intestinal damage, due to the possible presence of unfavorable microbes, comparable to hooligans, who are up to no good and like demolishing stuff.
Why? Just because they can.
How does it work?
Cruciferous vegetables contain an abundance of something called 'I3C', which you can compare to the abundance of tax you pay. Then that I3C ends up in your digestive tract and gets oxidized and then condensed into a compound called 'DIM'. (4)
This trajectory is similar to your tax money ending up into a government agency that handles your taxes, where your money gets 'oxidized' and 'condensed' into different departments. DIM is just one such department: Department of Internal Money making.
What DIM does is activate a receptor called AhR, which is in charge of the maintenance of the immune cells (IELS) mentioned earlier. (4)
You can compare this to the department of money making using some of the money to pay public services, like the police department. AhR is basically the salary for the little patrolling policemen in your intestine.
In other words, you need to eat your cruciferous veggies, otherwise your internal police department will go on strike.
Cruciferous vegetables are vegetables of the family Brassicaceae such as cauliflower, mustard greens, cabbage, kale, spinach, garden cress, bok choy, choy sum, broccoli, Brussels sprouts and similar green leafy vegetables, excluding lettuce.
There are scientists that claim that many kinds of mushrooms have the potential to provide us with the next generation of antibiotics, to reduce environmental pollution, and even produce our fuel. They even go as far as stating they are one of the great untapped resources of nature. (5)
That sounds amazing, but can our little fungi friends boost our immune system, while taking care of pollution?
The good news is, you don't have to resort to taking magic mushrooms to obtain these magic qualities.
Although you won't be going on a trip either.
Unless you are intolerant. In that case the only trips you will be taking are to the restroom.
More about intolerance under "Microbiome".
How can mushrooms supply you with this magic?
By supplying you with prebiotics to feed your microbiome (more on prebiotics under "Microbiome)
By increasing secretory IgA (8)
If you remember from the first article "The best ways to protect yourself against virus infections part 1" almost all infections are initiated at the moist or mucosal surfaces, like our eyes, nose, mouth and the inner lining of the digestive tract.
And these areas are protected by secretory IgA, our first line of defense against respiratory infections, which can neutralize viruses and prevent bacteria from playing cliffhanger on your epithelial cells. (9), (10)
At least one of the compounds in mushrooms, called beta glucan, is responsible for the ability to increase secretory IgA, as lots of trials have demonstrated beta-glucan supplements can do exactly that.
Beta glucan derived from 2 different mushrooms have even been licensed as successful drugs in Japan. (15)
Beta glucan is also found in yeasts such as nutritional yeast. Nutritional yeast is commercially sold and often touted as a health food, due to its beta glucan content. It may have favorable effects in this form as well, but it's not easy to find unbiased research. Unbiased means that the studies aren't funded by the (supplement) companies that stand to gain from positive outcomes.
3. VITAMINS AND MINERALS
Micronutrients, like vitamins and minerals, are essential nutrients the human body requires in order to perform its basic functions. Micronutrients are required for the metabolism of many compounds, among which carbohydrates, protein and fat. Micronutrients are important for cell development and genomic stability, and many of the micronutrients are necessary for DNA synthesis and repair. (16)
You can imagine then, since they are involved in so many processes, that they can also impact immunity.
So, should you take multivitamin and mineral (MVM) supplements then just to cover your bases?
Well, large-scale studies show that MVM supplements produce little harm or no harm in the short run. (19)
What about the long run?
It gets a little bit trickier here, because they may actually slightly increase your risk of cancer and cardiovascular disease. Misleading commercials and placebo effects may still please consumers despite, simply because they haven't been properly informed. (19)
Simply taking a MVM to cover your bases is not necessarily a good idea. It depends on your diet pattern and your overall gut health (what you absorb). It also depends on the supplement and its dosage.
Therefore, it's better to get professional advice from a certified nutrition expert.
What you should do in the meantime, is focus on the things that contain these micronutrients in their natural form: food
All foods contain some vitamins and minerals, but certain foods impact immune response more than others. Maybe that's because these foods contain a host of other nutrients or phytochemicals as well. These nutrients may not be essential in the same way as vitamins and minerals are, but they can still be beneficial. (20)
Foods that are not only rich in micronutrients, but also have favorable effects on your immune response are fruits and vegetables.
In 1983, they already realized that a greater fruit and vegetable consumption lead to a reduced risk of getting a cold. (21)
In people with a weaker immune system, older people, higher intake of fruits and vegetables improved immune function and showed a better response, in terms of the amount of antibodies produced, to a vaccine they were administered with. (22)
Another more vulnerable group, pregnant women, also benefited and showed to be less susceptible to upper respiratory infections during their pregnancy. (23)
But even if we look at a variety of people with a variety of conditions on a large scale, fruits and vegetables are clearly associated with improved immune responses. (24)
The term microbiome is often used when speaking about the microorganisms in the gut or gastrointestinal (GI) tract, sometimes also described as intestinal flora. Microbiome technically means the combination of the intestinal flora and their environment (the gut). (25)
Here we will focus on the bacteria in the GI tract and the important role they play in your immune system. Important is probably an understatement, because they fulfill so many roles in the human body. To put things in more perspective, the number of bacterial cells in the human body actually exceeds the number of human cells! (26)
Isn't that remarkable?!
We are more microbe-human-hybrid beings than we are in fact human beings.
Not surprising, that your friendly intestinal flora can stimulate and develop different components of your immune system.
It acts as a protective barrier, preventing pathogens from setting up shop in your gut. It starts right after birth when a 'barrier' of microbiota is formed.
The big question now is, how do you take care of your microbiome?
For newborns and infants breast milk contains beneficial bacteria and it feeds the beneficial bacteria as well, resulting in a healthy population of bacteria, promoting the development of the immune system. This may help also prevent conditions, such as eczema and asthma, common among young children. (27), (28)
If you are able to read this, chances are you are not living off breast milk.
There are other ways, thankfully, to tend your inner garden.
Diet has a major impact on the composition of your intestinal microbiota and your immune status. Gut bacteria can directly influence immune and epithelial cells by producing a compound called short chain fatty acids (SCFA's). (1)
Your intestinal epithelial cells are the physical barrier that separates your gut from the outside. This barrier prevents harmful bacteria and substances from getting through. BUT, it is only a single cell layer thick! (29)
SCFA is key in maintaining these fragile epithelial cells and promotes intestinal IgA responses, contributing to the protection of foreign invaders. (30)
That's one of the reasons, you really need to feed your microbiome well.
How do bacteria produce SCFA's?
They produce SCFA's mainly from different non-digestible carbohydrates, such as fiber.
Foods that contain carbohydrates often contain a variety of different non-digestible carbohydrates. We call these compounds that feed our friendly flora: PREBIOTICS. (31)
If you are considering a low carbohydrate diet, realize that one of the more common species of beneficial flora, Bifidobacterium Bifidum, harbours specific carbohydrate transporters allowing them to protect the epithelial cells. (32)
In what foods can we find prebiotics?
In vegetables and fruit, whole grains, legumes, nuts and seeds. And let's not forget our previously discussed friend mushroom, which hosts an abundance of prebiotics.
A note to make is that, if you have any food intolerances towards any of these prebiotic-rich foods, they can be a cause of inflammation and will more likely to have the opposite effect and weaken your immune system instead. (33)
The causes of food intolerances can be multifold. If your intestinal health is impaired, that could lead to food intolerances even by itself. (33)
If you are aware what foods you are sensitive to, exclude them from your diet for the time being and keep feeding your microbiome with a variety of foods you can handle.
Foods you are sensitive to and cause you digestive discomfort, itchy skin or other symptoms, can be reintroduced slowly over time, similar to the protocol commonly use among low FODMAP diets.
FODMAPS are different (non-) digestible carbohydrates that are first minimized, before being carefully reintroduced several weeks or months down the line.
Food allergies are not the same as food intolerances and can't be treated the same way. A food allergy is a direct response of the immune system to a food, which negatively impacts your health. (34)
More on this in a future article.
Your microbiota can boost your immune system in other ways too.
There are several other things your good bacteria can produce, that can contribute directly and indirectly to an enhanced immune response.
They can even produce vitamins, of which you already know, are a key factor in shaping a good immune system. (1)
Prebiotics can feed the bacteria that help and produce a soothing balm for your insides.
Probiotics are live microorganisms (mostly bacteria) which are often sold in supplement form or used to make, for instance, yogurt.
Different kinds of yogurt have become increasingly popular over the years and yogurt is, besides dairy, nowadays made from a variety of foods, such as soy, almonds, cashew and coconut.
Also getting more popular are fermented vegetables like sauerkraut or kimchi.
They also contain probiotics, but since they are fermented with naturally present microbes, they may be more suitable for our microbiome, provided that they are raw and not pasteurized or heated.
Don't go overboard on serving sizes, especially when you're just starting out, because it's very powerful stuff.
Probiotic studies have shown promising results in respect to our immune system. (35)
Whether to take probiotics in supplement form or not, to give your immune system a little boost, is a complicated issue unfortunately.
It depends on your individual microbiome and which species and strains of beneficial bacteria are possibly lacking.
Many factors, such as age, hormonal perturbations, diet composition and supplement intake, antibiotic therapies, lifestyle, disrupted circadian rhythm (natural day and night rhythm) and physical activity all have an impact on your gut microbiome. (36), (37)
Antibiotics deserve to be emphasized, because they can have such a drastic effect on your microbiome. They can be life-saving in some cases, but they are also able to cause LASTING CHANGES, disrupting intestinal harmony by wiping out beneficial microorganisms. This can lead to all sorts of health problems, including weakened immunity. (38)
Not only that, you can reduce the damage caused by the antibiotics by frequently reintroducing beneficial bacteria, that may otherwise get hurt in the line of duty. That line of duty may feel like a nuclear bomb for some bacterial strains, so they need some help or reinforcements down there.
If antibiotics are the nuclear bombs for our friendly little troops, alcohol is one of those small little bombs, that do some damage, but significantly less.
After that little bomb has dropped, ground troops are more able to regroup and do some damage control, taking care of the wounded and rebuild, whereas after a nuclear bomb has dropped, they would like to do all these things, but they can't because their bodies have become disintegrated.
Alcohol can reduce the total numbers of your intestinal flora, needed for healthy gut immunity. Alcohol disrupts the relationship between the microorganisms and the intestinal immune system. Alcohol damages your gut lining, or the epithelial cells, resulting in holes that form in the barrier function. (41)
Like mentioned above, troops can regroup and rebuild, but the more little bombs land, the more holes will form in their barrier or defences and the more helpless they will become. In this case that means frequent alcohol consumption will more negatively affect gut immunity.
Diet has a big impact on how your immune system operates.
A healthy microbiome is the most important component in forming a healthy immune system. Our friendly flora requires food in the form of vegetables, fruit, legumes, whole grains, mushrooms, nuts and seeds in order to produce the substances that protect our gut and thus strengthen our immunity.
Some of these foods have special immune enhancing qualities, like cruciferous vegetables and mushrooms.
Individual food sensitivities, even of healthy prebiotic-rich foods, can negatively impact your immune system and alcohol is harmful to your gut lining and your friendly microbes.
Common Beliefs to Prevent Colds, True or False?
We've discussed the most important lifestyle and dietary factors that influence our immune responses to various virus infection like the flu, the common cold or more serious infections like a coronavirus.
Many people have their own beliefs about things that work or things that don't work against coming down with the flu for example. Some advice has been passed down for generations.
Next article will look into common beliefs and questions such as:
Will cold (exposure) make you sick?
Does Vitamin C protect you from getting a cold?
Can hot soup speed up your recovery time?
Do you need to drink more water?
How truthful are they?
Find out next time!