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What you need to know about nutrition and the immune system: Staying strong with TBI

Save your screen time! Audio of this article found here:

Whether it’s a regular cold & flu season or a worldwide pandemic, you are maybe looking to do whatever you can to ‘boost’ your immune system. You’ve likely seen a number of articles and products on the topic, and maybe you’ve even loaded up on some supplements ‘just in case.’

I can’t blame you. Especially during this unique global situation we are in. But I know you want the information without the fear. Indeed, I’ve seen people in the concussion community worried and wondering if brain injury puts you at higher risk of getting ill…

So based on viewer request, I have for you some key information that can help you feel strong about your nutrition and your immune system.

What do I need to know about the immune system?

You’ve heard people say “boost your immune system!” I’m not sure this is totally accurate. Claims to “boost” your immune system make it sound like more is always better. But your immune system isn’t so ‘all or nothing.’

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Let’s imagine your body is like your home. Your home is protected in many different ways: the walls of your building block out damaging weather; you clean your home from time-to-time to get rid of dirt brought in from outdoors; and if a light goes out, you will fix it so that you don’t fumble around in the dark.

Your immune system acts in a very similar way: there are barriers and check-points in your digestive tract that limit entry of damaging substances; different cells in your immune system break-down and get rid of particles that are not needed in the body; and certain cells can signal repair to a damaged area.

Where we run into problems with the immune system is when it’s, how I like to think of it, ‘under-active,’ ‘over-active,’ or ‘overwhelmed’.

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An ‘under-active’ immune system is seen at different ages and with certain illnesses. Have you noticed kids tend to get more colds & flu? That’s because their immune system is not fully built yet — as if your home had the roof and some windows missing. Then past age 65, your immune system naturally slows down — like a home after many years may no longer insulate as well due to regular wear & tear.

An ‘over-active’ immune system is also problematic. For example, post brain injury, an over-excited immune response leads to inflammation in the brain, which is thought to contribute to ongoing symptoms (I wrote about this for you here in a post about anti-inflammatory eating). Imagine this overreaction to be like cleaning your home 24/7 with no time for anything else! Or ten people all at once trying to change that lightbulb — frustrating!

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An ‘over-whelmed’ immune system is what might happen when you catch a really nasty virus. Your immune system may be working as well as it ever did, but there’s just too much work. Imagine sweeping your home, then all of a sudden your windows got smashed, people came in and poured buckets of dirt everywhere, and all the lights went out. It might be more than you could handle, and you maybe wouldn’t have all the tools you need to deal with it.

Just like you want a good housework-life balance, you also want a well-balanced, well-functioning immune system 🙂

Does my brain injury lower my immune system? Can I get sick easier?

We’re learning more and more that an injury to the brain affects many parts of the body. So it’s natural that people may ponder whether this extends to the immune system.

As noted above, an injury to the brain can cause a heightened immune response that doesn’t really help us. But it’s not the entire immune system that does this. Your immune system is a very large team with many different members.

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The team members that cause inflammation in the brain post injury aren’t necessarily the same as those who keep bacteria & viruses in check. In fact, some researchers are targeting the specific inflammation-causing team members in the brain — a recent study showed that suppressing these specific immune team members (aka microglial cells) in the brain of mice helped the mice recover better from brain injury.

But what about the team members of the immune system that help with bacteria & viruses?

When it comes to concussion & mild TBI, there aren’t really any studies that show a higher risk of infection or illness in rehab. However, risk of infection in hospitalized brain injury patients is rather well know.

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Research articles talk about how within hours of severe brain damage & stroke, important immune cells called T-cells don’t work as well. With fewer of these T-team members circulating around weeks after the injury, we may see more infections in hospital. This is thought to be short term and may take up to 3 months to start working normally again.

It seems clear that soon after a severe brain injury, the immune system that helps prevent infections is not working so well. But truth is, we just don’t know how much this relates to mild TBI or concussion.

One author does suggest that regardless we should keep a high standard of care no matter the type or severity of TBI. Even if it seems the injury itself doesn’t affect your immune system, stress & lack of sleep, which are common post TBI, definitely do.

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It’s not my place to say for sure whether your immune system was affected by your TBI. I’m just here to present to you what I have found in the research, to help answer your questions. Taking all this evidence together suggests that unless your injury was severe and recent, there’s no proof that your immune system is affected — I found no evidence that a person with a concussion or PCS is at higher risk.

If you feel like you have experienced more cold & flu since your injury, there are other indirect factors to take into consideration: more stress, lack of sleep & exercise, and possibly not being able to get your full nutrition.

How can I keep my immune system working well through food?

Your immune system, like any other system in the body, needs a number of nutrients to do it’s job. Just like your house needs drywall and you need repair tools.

So here I break down for you 3 aspects of nutrition for your immune system:

  1. Lower the workload on your immune system
  2. Make sure your body has the nutrients it needs to deal with issues when they arise
  3. Maintain the barriers that check entry of damaging substances
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#1 Lower the workload on your immune system

When your home is kept safe from extreme weather, it will need less maintenance. Same goes for your immune system — it will have less work to do if you lower your chances of food borne illnesses.

You’ve already heard a million times by now to wash your hands. This is one crucial step. And there are others that involve the food itself?

Your food will last longer and will be less likely to harbour harmful bacteria if it’s stored & cooked at the proper times & temperatures. I will direct you to a detailed resource here, but here are some basic ideas:

  • Don’t let food sit out on the counter for longer than 2 hours if it needs to be refrigerated or cooked.
  • Use a food thermometer to take the temperature of foods you cook & reheat. They are safer when they have reached a safe internal temperature.
  • Most foods that are kept in the fridge are good for up to 4 days (or by their best-before-date if it’s marked).
  • Wash produce under cool running water. Not with soap. Produce is porous so soap residue can get right in there, which is not great for consumption.
Photo courtesy of USDA.

You can also find a video with transcript on safe food handling for people with weakened immune systems here.

#2 Make sure your body has the nutrients it needs to deal with issues when they arise

When it comes to a well-functioning immune system, you can pretty much get everything you need from a well-rounded diet. Key nutrients for the immune system are found in many foods and dietary patterns, such as the Mediterranean style of eating:

  • Vitamin A in goat cheese, eggs, pumpkin & spinach
  • Vitamin B6 chickpeas, fish, potatoes, bananas, bulgur
  • Vitamin B12 in fish, liver, milk products and nutritional yeast
  • Vitamin C in citrus fruit, bell peppers, broccoli, Brussel sprouts
  • Vitamin D in milk & alternatives, fish, mushrooms
  • Vitamin E in oils, nuts & seeds
  • Zinc in pork chops, baked beans, chicken, pumpkin seeds, cashews, yogurt
  • Folate in leafy green veggies and fortified grains (cereals & pastas)

You may be wondering about supplements. Ask yourself these questions to better understand whether supplements are right for you:

Do I have a history of low blood levels or dietary intake of those key nutrients?

  • Some people I work with already have low B12 or vitamin D for reasons related to family history or other health issues.

Am I an athlete?

  • If you’re getting back to your sport, intense physical activity can suppress the immune system. Vitamin C supplementation might lower the rate of the common cold.
  • Supplements also need to be as safe as possible — there is always a risk that they may cause a positive doping test.

Is there any good proof that this supplement actually works?

  • There is no proof that supplementing any of the key nutrients truly helps with preventing cold or flu.
  • There is some evidence that shows zinc lozenges taken at the start of a cold can help lower the severity and length of the cold. Keep in mind, this is NOT for young children. And if you want to try, this is only safe for a short period of time — the dose is high and chronic use can cause problems.
  • When day light hours are reduced, it’s almost impossible for people to get enough vitamin D from the sun. Supplementing this throughout the winter months isn’t a bad idea.

#3 Maintain the barriers that check entry of damaging substances

We hear a lot these days about a healthy gut being good for the brain. The gut does so much for us! This is the first point of contact for many things that enter your body. As such, there are these sort of immune system centres along the digestive tract. So keeping these surfaces healthy is important for your overall immune health.

Starting in the mouth, a dry mouth or one with dental problems is more likely to pass unpleasant bacteria into your bloodstream. Oral health has also been linked to a number of autoimmune diseases. So brushing & flossing are important for immunity too!

When it comes to the rest of the gut, I’m seeing a trend in people with TBI — a number of people who come to me are dealing with some form of digestive issue. This is usually the first place I start with your nutrition. Because if your gut is irritated, it won’t absorb those (or any) key nutrients very well. The irritation just might affect those immune centres too.

There’s no one way to heal gut nutrition — you need a plan that looks at your symptoms as a whole and helps pinpoint the cause of your gut irritation. Just like your brain symptoms, no two gut issues are totally the same.

Your nutrition will help make a safe & happy home for your body, but it won’t prevent unwanted guests at the door

What’s important to know is that no matter how well your immune system is functioning, it doesn’t stop a bacteria or virus from contacting your body and potentially causing infection or illness.

Keeping yourself healthy through nutrition, exercise, sleep and stress management makes your immune system more resilient to dealing with the trials on your body. Currently the only way to truly lower your risk of serious infection during this pandemic is hand washing and physical distancing.

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But keep up the social contact! Call your family, message your friends, or leave me a comment 🙂 I would love to hear what’s on your mind for nutrition.

Best in health,

Krystal Merrells, Registered Dietitian


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