How to eat (and what to take) to build a healthy immune system

Updated: Apr 27


Immune boosting foods

I wanted to take a moment to walk you through your immune system and the foods, nutrients, and other habits that can boost or weaken it. When you think about your immune system, it helps to think about it as an army. Vitamins, minerals, and other compounds are like the machinery for the cells that make up the army, and certain factors, like having chronic conditions or not getting sufficient sleep, can undermine this army and weaken its defenses. Before we go any further, let’s get clear on one thing: Eating well and potentially supplementing can help keep your defenses up, but nothing is a substitute for other legitimate protective precautions, like social distancing, hand washing, proper disinfecting, and avoiding touching your face. Below are some nutrients, foods, and habits that are natural immune boosters.


Protect Your Gut

The majority of your immune system is located in your gut, which is one reason gut health is so key! To protect the lining of your GI tract and to build a healthy microbiome, you need to focus on three key areas:

1. Eat a diverse range of fiber-rich foods. These foods supply pre-biotics that act like a buffet line for your gut bacteria, enabling them to thrive. Aim for at least 25 grams of fiber each day from whole food plant sources, like veggies, fruits, pulses (beans, lentils, and peas), whole grains, nuts, and seeds.

2. Enjoy colorful foods. These foods tend to be rich in polyphenols, which are broken down into food that fuels the healthy gut bacteria. Plant-based, fiber-rich foods also supply other natural immune boosters, so it’s a good idea to make these foods the foundation of your diet.

3. Have fermented foods and/or supplement with probiotics. Whether in fermented foods or supplements, probiotics are live microorganisms that are basically implanted in your gut.

Focus on Natural Immune Boosters in Your Diet

There are a number of different vitamins, minerals, and other compounds that build up your internal army. Chief among them are: Protein, B vitamins, Vitamins C, D, and E, carotenoids, selenium, magnesium, zinc, iron, copper, pre- and probiotics, and glutamine. I’ll break a few of these down.

  • Vitamin D. Vitamin D is rare in food, but can be found in wild salmon, pasture-raised eggs, and some mushrooms. I generally recommend supplementing with this nutrient and this may be especially important during the coronavirus crisis. For more on this, read my post Best Supplements for Your Health.

  • Vitamin C. This powerful antioxidant is deeply involved in your immune response, but it’s generally easy to get from food. In addition to citrus fruits, rich sources of this immune booster include red peppers, strawberries, broccoli, and Brussels sprouts. You’ll hit your daily target by including a range of fruits and veggies, but just to show you how easy it is, you can also check the box by drinking ¾ cup of 100% OJ. Pro tip: I often add a splash of 100% OJ to sweeten a smoothie or seltzer.

  • Zinc. Zinc is needed to activate certain immune cells and while it’s easy to come by in your diet from sources like seafood, pumpkin seeds, cashews, and chickpeas in addition to beef and dark meat chicken. Since this nutrient is a vital natural immune booster, it’s important to get a sufficient supply through food and potentially a multivitamin. If you do use a multi, make sure you’re buying an age and gender specific version, and one that doesn’t exceed 100% of your needs for most of the nutrients.

  • Omega 3s. These fats supply some of the raw materials your immune system needs, and they’re found in oily fish, like salmon and sardines, as well as flax, hemp, chia seeds, and walnuts. You can boost your intake by meeting the government’s suggestion to eat two servings of seafood a week and potentially taking a supplement.

  • Magnesium. This key mineral is found in very common foods, like leafy greens, pulses, whole grains, and dark chocolate, but most of us don’t get enough of these foods or extra stress, medications, or chronic conditions alter our status. Magnesium is part of your immune machinery and it’s also involved in helping your body weather stress better and sleep better, which are both factors that can support your overall immune health. Since multivitamins contain very little magnesium, I often suggest supplementing. You can find more about that in my post Magnesium is One Supplement You Should Pay Attention To.

Create an Immune Boosting Eating Pattern


If you see a common thread here, it’s that 75% of your diet should include whole, plant-based foods. This holds up whether you also include animal products or not. Instead of looking at creating a meal around meat, look at creating a meal around plant foods and add meat (or chicken or turkey or any animal source) as desired. Here’s how to get the most immune boosting nutrients through your food.

  • Make whole, plant-based foods the base of your menu. They should take up 75% of your plate at each eating occasion.

  • Focus on fruits and vegetables. These foods supply the antioxidants and carotenoids that protect your cells from destructive, free radical damage. Make them half your plate.

  • Have healthy, plant-based fats. Foods, like nuts, seeds, avocados, olives, and their butters and oils help regulate the inflammatory process and supply some immune supporting nutrients.

  • Eat pulses every day. Pulses are the umbrella term for beans, chickpeas, lentils and peas, and these foods are rich in many of the micronutrients that give your army the materials it needs to boost its defenses.

  • Have seafood twice a week. This will help supply vitamin D naturally, as well as zinc and other nutrients. It’s also a prime source of protein.

  • Supplement sparingly as needed. There are definitely supplements, like vitamin D, magnesium, probiotics, Omega 3s, and a multivitamin, that can be very useful, but they should be used as added support. Think of them as your plan B instead of your plan A, which is to eat well and practice other healthy habits. When you do use supplements, talk to your RD to determine which ones are right for you based on your diet and individual needs. Some can be toxic if used in high amounts!

To support this eating pattern, download my FREE recipe booklet with 10 easy meal and snack recipes that you can make in 10 minutes tops!

Support Your Immune System with Healthy Habits

It’s not enough to just eat well, though that’s a huge part of creating a healthy defense system. Here are some other healthy habits that will keep your immune system in good shape.

  • Stay well hydrated.

  • Aim to get 7-9 hours of sleep every night. You should wake up with energy to fuel your day (though it may take a few minutes!)

  • Practice deep breathing or meditation. The deep breathing exercises calm your nervous system down and support healthy digestion to aid in a healthy gut environment.

  • Stay as active as you can. There are many reasons to exercise, but one of them is that it offsets the risk of other conditions that can make you more susceptible to infections.

Watch Out for Immune Wreckers

We know eating highly processed foods, including those high in added sugars and refined grains, can result in getting inadequate intake of certain nutrients and put you at higher risk of certain diseases that weaken your immune system and raise your risk of infection. When you think about your army, you need to support it with the right machinery (AKA your nutrients), but also by limiting the things that weaken or impair it. Do your best to focus on the foods that naturally boost your immune system and limit those that undermine it.

REFERENCES

If you want to geek out on the science with me, references are below!

1. http://www.bmbtrj.org/article.asp?issn=2588-9834;year=2018;volume=2;issue=3;spage=168;epage=172;aulast=Farhadi

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723551/

3. https://www.preprints.org/manuscript/202003.0235/v2

4. https://pubmed.ncbi.nlm.nih.gov/30336639/

© 2017-2020 Samantha Cassetty Nutrition & Wellness, LLC. All rights reserved.
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