How To Boost The Immune System

...and Keep Your Clients Healthy

Written by: Dr. Marc Morris CSCS

It’s that time of the year and NO ONE LIKES TO BE SICK. 

And for many, especially your clients focusing on their nutrition and health goals, getting sick is a setback they want to minimize or avoid altogether. 

That’s why in this article I’ll show you the science of “immune-boosting” and a step-by-step strategy to coach your clients through their sickness, so they can get right back to tackling their health goals. 

Here we go! 

Cold and Flu Season

We are now entering flu and cold season, and there’s not much we can do about that. 

But is there anything we can do to avoid getting sick? 

This is an important question and one I know your nutrition clients are asking all the time. 

“I feel like I’m getting sick all the time, this cold, just won’t go away, do I even have an immune system?”

Ok, great. Before we get too far, let’s talk about the “immune system”. Because it’s in the middle of all of this. 

Your immune system, is our natural defence system against foreign invaders, from things like bacteria and viruses which we’ll talk about today, but also things like toxins to even healing wounds. 

This is what helps us get better and recover. 

On a daily basis, you are exposed to potentially harmful bacteria and viruses, which your immune system recognizes and deals with right away. 

So the key here is keeping your immune system healthy all year, not just in cold and flu season, to prevent infection and even disease. 

Your immune system is a complex, interconnected system, with two main layers here, the innate and adaptive immune systems. 

Innate Immunity is your first line of defence. You can think of innate immunity as protective barriers, skin that defends and separates, stomach acid that destroys, and immune system cells that attack things that are normal. 

It’s not specific, it just senses danger and does its thing... 

Whereas your adaptive immunity is smart and learns to recognize the invader.

You have cells located in tissue all over your body that learn and remember specific, harmful substances so they can destroy them. 

They do this by creating antibodies, which recruit more immune cells, for a more efficient and quick response. 

That’s how our immune system functions, both in protecting you from getting sick and also in reducing the severity 

“Ok that’s great, is there anything I can do to boost my immune system?”

Unfortunately, no not really, in the way you may think of it, like taking a supplement or special food and everything is enhanced. 

Here’s what the science says does work, to strengthen, or at least prepare your immune system, for pathogens and disease.


Evidence For What Works

There is no guarantee that you won’t get sick, but there are some things to get better quicker. 

Sure there is. 

Let’s think about this in two phases. Long Term and Practical Application


There are things you should be doing year-round to maintain your immunity. 

Sure it’s common during cold and flu season to want to seek out special foods and supplements, but in most cases, it’s not one specific thing that will keep you healthy. 

Let’s take a look at the big picture. Starting with...


Balanced Diet

Consuming enough nutrients as part of a balanced diet, within the amounts you need to reach your health goals, is important for overall health, but also for your immunity and immune cells. 

Although there is probably nothing special about specific foods, the immune system does need specific nutrients, like vitamin C, vitamin D, zinc, selenium and iron to function. 

As well as an overall protein and energy intake that supports healthy functioning. 

These nutrients can be found in a variety of plant and animal foods and should make up a healthy and balanced diet. 

Outside of that, research suggests avoiding ultra-processed foods like sugary drinks, storebought cookies and chips etc can negatively impact the immune system. 

And since your gut is one the primary locations responsible for keeping pathogens out of your body

Not a bad idea to include adequate overall fibre (14 grams for every 1000 kcal consumed) and potentially other pre-and probiotics. 


Sleep and immunity go hand-in-hand. 

Since sleep is the time your body rests and recovers, a healthy immune system needs enough sleep. 

Adults should be aiming for 7 to 9 hours of quality time of sleep per night

Adults that get less than that, were shown to be more likely to get sick. 

Prioritizing and managing sleep is easy with the right sleep hygiene. 

Sleep hygiene is just what health experts call the good sleep habits that set you up for a restful night’s sleep. 

Some helpful ones include: 

  • Going to bed at the same time each night and keeping a schedule
  • Minimizing caffeine later in the day
  • Sleeping in a cool, dark room
  • Limiting screens and blue light sources to close to bedtime

What else can help? How about…



Now keep in mind, being hydrated won’t necessarily protect you from getting sick, but being dehydrated makes you more susceptible to sickness and disease. 

Plus it’s important to your overall health. For men, aiming for around 4 litres of fluid is optimal per day, whereas women should be closer to 3 litres. 

There is room to be more specific with these numbers depending on the individual.  

Outside of that, and this isn’t really my area of expertise, but try to limit excess stress when possible. 

If that vague advice isn’t helpful. which I’m sure it isn’t, regular exercise and mindfulness techniques, like meditation or breathing exercises may help, if you find you get sick a lot and stress is to blame. 

NOW, keep in mind, there are other factors that can depress your immune system, like age and being immunocompromised. 

You are probably wondering, “Ok but I do all that, and I’m sick. I want to take something, can’t I take something?” 

Fair enough, here are some suggestions that don’t have tons of evidence, but won’t harm you or set you back, so as long as you’re fine spending your money on something that may not help, go for it.

Since many nutrients are necessary for the immune system, many people will take them in the form of supplements or food when they get sick.


Vitamins, Minerals, and Supplements

Vitamin D 

Vitamin D deficiency increases your risk of getting sick, but there don’t seem to be extra benefits when adequate levels have been met. 

Most people living in cold climates should supplement with vitamin D (exact amounts depend on blood levels)...  

Vitamin C

Vitamin C is the most popular vitamin for the common cold, giving rise to the popularity of citrus fruits as well.

It may be effective, in 11,000 adults taking between 1000-2000 mg of Vitamin C per day cold duration was decreased by 8%, although it had no influence on preventing the cold. 


Supplementing with Zinc may help protect against tract infections. 

In a review of 575 people with the common cold, taking more than 75 mg per day reduced the duration of the common cold by 39%. 


Garlic may enhance immune health, mainly from its anti-inflammatory and anti-viral properties. 

One study showed supplementing with Garlic decreased the incidence of the common cold by 30%. 


Elderberry is popular in cold and flu season since it’s long been used to treat an infection. Some research has been shown to reduce the severity, duration and symptoms of the common cold. 

There is some extra risk with elderberry supplementation, so use it in the direction of a qualified healthcare professional. 


Practical Application

Alright, you’ve already fallen ill. How should you adjust eating and training?

Here’s the deal. 

This is something that's a short-term issue. Totally manageable. 

I know you’re super dedicated to your nutrition and training and probably don’t want anything to change, BUT this is how you need to view this: 

“Don’t let this short-term issue turn into a long-term setback by not taking care of yourself”.

Here are my suggestions and what you should adjust: 

Instead of just putting your head down and sticking to the exact same plan, which could make this process so much longer, here’s my best advice: 

For nutrition, everyone needs to manage this differently. For the next 2-3  days your food targets can be much more flexible and truthfully you don’t need to track at all. 

Because the emphasis needs to be on doing what you need to do to get better. 

For many, this looks like more comfort foods or carbs. 

For some, it looks like additional fluid and carb drinks. 

And some people don’t feel up to eating much at all. 

Listen to your body and do what you need to do to feel better 3 days from now instead of being stubborn and pushing through. 

That’s nutrition. 

For training, this is optional as well. 

I know you want to keep up with it to tick boxes, but since you don’t have a hard deadline on what you’re trying to accomplish, it doesn’t make much sense to just complete some arbitrary plan. 

NOW, if lifting makes you feel better and you’re not putting anyone else in harm's way, go for it. 

But for many people, it's always best to take 2-3 days off, get outside to walk, and resume in a better place.

And that’s it, folks, those are the best ways to boost your immune system during cold and flu season. 

Now if you’ve found this blog post helpful, go ahead and share it with all your sick friends.


And if you enjoyed all of those tips, you’re really going to love the article I have linked up here.

Now that you have a better understanding of the science of immunity, learn more about the science of gut health.

So make sure to check it out now and I’ll see you next time. 

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