How Diet and Lifestyle Affects Immune Health

Author: Polly Breitenkamp RN, BSN, NTP

As we’re in the throes of the winter season, this is an excellent time to look at our diet and lifestyle and how it’s serving us. What do I mean by that? Winter is the time of year when we catch colds, contract the flu and other viruses, and potentially spread it amongst others. While there is a LOT of education on how to minimize exposure and increase sanitation, there is not much emphasis on building our terrain. So what helps keep our immune system robust and thriving?

Using Food-as-Medicine: What to Remove

Let’s start with the diet. We want to begin with removing processed foods and eating natural, whole foods as much as possible. Processed foods have added sugars, industrialized oils, additives, and chemicals that cause a lot of infl ammation. These types of foods feed harmful bacteria, compromise the intestinal lining allowing undigested foods, viruses, bacteria, etc., into the bloodstream where they don’t belong, and set off inflammatory responses. While inflammation is important because its the body’s way of attacking foreign invaders, we don’t want it to become chronic. We don’t want it to be left “on.”

The immune system has two main jobs. The first is to attack whatever foreign invader is causing the problem. The second is to keep the entire system reigned in, so once the foreign invader is vanquished, the system will turn off. This second part is vital. Otherwise, we could catch a cold, and our immune system would never turn off again! Normally, the immune system activates an acute response. For example, when we get a cut or a sliver, acute infl ammation is started. When we’re exposed to a virus, the adaptive immune system is triggered. While this is going on, the rest of the immune system stays restrained, making sure things don’t get out of hand. In the case of chronic infl ammation, our bodies lose the ability to balance the two separate functions, causing them to go awry.

When we have chronic stress, persistent infections, or eat proinflammatory foods, the signals to produce inflammation become chronic. Then when we add in nutrient deficiencies and poor sleep, the part of the immune system that keeps it regulated becomes ineffi cient. This is when we can get widespread body inflammation, damaging healthy tissues along the way. While Chronic inflammation isn’t necessarily the cause, it contributes to ALL chronic diseases: Heart disease, diabetes, autoimmune diseases, and cancer.

This is where our diet and lifestyle come into play. How much inflammation we have is a direct result of how we eat, how we sleep, how active we are, how much stress we’re under, the amount of toxins we’re exposed to, and if we have any underlying infections that aren’t being addressed.

Using Food-as-Medicine: What to Add

Circling back to our diet, we know what to remove and why, so now the question becomes, what do we add?

It’s important to understand that the immune system is a nutrient hog, especially the part responsible for turning it off. It needs a vast array of nutrients, including essential fatty acids, essential amino acids, vitamins, minerals, and plant phytochemicals.


1. Nutrient-dense proteins: 4-6oz, high-quality meats/fi sh (pastureraised, grass-fed, wild-caught).

2. Tons of veggies: aiming for 2-3 servings/meal.

3. Eating the rainbow: choose vegetables of different colors.

4. Mixing up raw vs. cooked: vary how you prepare your veggies (juices, salads, steamed, roasted, sautéed).

5. Slow-burning carbs: choose starchy roots and tubers.

6. Phytochemical-rich fruits: berries and citrus pack more antioxidant bang for your buck.

7. Nuts and seeds as condiments: aim for up to 1 oz of nuts and seeds/day.

8. Choose high-quality fats for cooking and dressing: olive oil, avocado oil, coconut oil, grass-fed butter or ghee.

9. Use fresh herbs and spices: they provide a ton of flavor and are packed with vitamins and minerals.

10. Cook at home most of the time: take control over your food quality; when eating out, choose farm-to-table restaurants.


While this is a year-round template, sometimes we need to give it a boost if we get sick. A few things we can add:


Probiotic supplements and foods populate beneficial bacteria. Beneficial bacteria collaborate with immune cells, and their response to infection. Fun fact: 80% of our immune system resides in our gut. What we eat has a direct impact on our immunity.

Some examples are:

1. Dairy-free yogurt

Dairy drives phlegm and mucous, so coconut-based or cashewbased are also options that still contain a creamy consistency.

2. Kombucha

Kombucha is a fermented tea that contains live cultures of healthy bacteria and usually has an ingredient, like ginger, that works as an expectorant to loosen mucous.

3. Fermented vegetables

Sauerkraut, pickles, carrots, beets, or other fermented veggies provide a broad range of benefi cial bacteria.


Garlic has a compound called allicin that gives it antiviral, antibacterial, and anti-parasitic effects. It’s a verypowerful fighter to help boost our WBC production to attack foreign invaders. We can use garlic as a base to almost any recipe by sautéing it with a bit of onion before adding other ingredients. It’s an excellent base for any soup, sauce, cooked veggies, etc., and it works well with many flavor profiles. Another option would be to roast a whole head of garlic. Just crosssection it at the head of the bulb and expose each of the cloves. Then add a pat of grass-fed butter with a sprinkle of sea salt, wrap it in foil, and roast it at 350 degrees for about 15-20 minutes. After it has cooled a bit, squeeze out the cloves. You can eat it whole or mix it with a little grass-fed butter to make a spread.


Making a simple bone broth does wonders for our gut health and immune system. Bone broth is rich in amino acids. Two particular amino acids found in the bones are cysteine and glutamine. Cystine mimics acetylcysteine, which is a compound found in bronchitis medications to relieve chest congestion. And glutamine improves the intestinal lining, making it less permeable, and
reducing infection risk.


1. Start by filling a pot with water and adding a rotisserie chicken carcass that has a little bit of meat on the bones.
2. Quarter an onion, chop 3-4 carrots and celery into thirds, and add to pot.
3. Add 1-2 tablespoons of apple cider vinegar to leach the minerals out of the bone to get optimal mineral content.
4. Add 1-2 tablespoons of sea salt. Sea salt helps to thin our mucous ducts keeping the mucous moist to discourage bacteria build up.
5. Bring pot to a boil, then reduce it to a simmer. Cover and let sit for 10-12 hours.
6. Let cool ,then strain. Now you have a great bone broth to drink by itself or to use as a soup base!

Final Thoughts

These are only a few examples of food that boost the immune system through the winter season. We also want to optimize our Vitamin D and reduce stress while increasing our resilience. This can be done by exercising, time-restricted eating, getting adequate sleep, meditation, having fun/laughter, and connecting with nature, family, friends, and pets. I hope by connecting the dots on how diet and lifestyle affect the way our immune systems work, we may become more proactive with our health.