Nutrients to Support the Immune System

Jan 17, 2023 | Nutritional Information


Cold & flu season is here, and with it comes lots of infection. If you have young or school-aged children, you are likely catching every virus out there. Your body is designed to manage these viruses on its own, and there are many holistic strategies that we can use to support the body’s natural immune defenses.


Immune System 101

Your body has two immune systems: the innate immune system and the adaptive immune system. Our innate system is what we are born with: it makes up the physical barriers of the body, like the skin and the mucous membranes, which are the linings of the respiratory system, urinary system and digestive system. This immune system provides a first line of defense against invaders that it immediately recognizes such as parasites, worms, and cancerous cells. 


The adaptive immune system is that which we want to train and support. When we encounter a virus, for example, we make antibodies so that we can recognize that virus again and mount a quick immune response. This is the system utilized with vaccinations. 


When we speak of viruses like influenza, the common cold, and COVID-19, we want the body to recognize these viruses and mount an immune response to help our body fight them off. Antibiotics do not protect against viruses; they are meant for bacterial infections. Viruses enter and multiply in our own cells, so medication does nothing to fight the virus, and is used to manage symptoms only.


Nutrients Needed for a Strong Immune System


Vitamin C

This is a vitamin most people associate with the immune system, and for good reason. It works by stimulating white blood cells, which are cells that help fight off infections. It is also an antioxidant, which means it protects your cells against free radical molecules which wreak havoc in the body, from things like toxins and pollutants. Smokers, for example, require additional antioxidants to protect against free radical molecules released by cigarette smoke. 


Vitamin C enhances the actions of phagocytes, which are key immune cells that ingest and destroy invaders (1). It also enhances the levels of antibodies in the body, which are a key part of the adaptive immune system, as well as modulating inflammation (1).

Your body is not able to make this vitamin itself, so it must be consumed through food and/or supplementation. Vitamin C is a water-soluble vitamin, meaning your body does not store it and the excess is excreted.


You can supplement with vitamin C about 500-1000 mg per day as needed to fight infections. More is also safe, but can be hard on the digestive system; about 1000mg for the common cold or influenza should be sufficient. 


Foods high in vitamin C include:

  • Tomatoes, bell peppers
  • Broccoli
  • Citrus fruits, strawberries


Vitamin D

This vitamin has had a lot of mainstream attention since 2020. It has been widely studied for its association with the immune system, and is particularly helpful for those with autoimmunity as it regulates the inflammatory response.

Multiple studies have shown the link between lower vitamin D levels and  increased infection rates with influenza, bacterial vaginosis and HIV (2). Where it shines is in its ability to shift the inflammatory response from a pro-inflammatory state to an anti-inflammatory one. This can be helpful for managing inflammation during an infection and for those with chronic inflammatory conditions (2).

Supplementation with vitamin D is recommended for people in North America, as the sun is not strong enough during the winter months to allow the skin to synthesize vitamin D, and typical diets are not rich in vitamin D. In most of Canada, October to May is a good time to supplement.

This is a fat-soluble vitamin, meaning your body is able to store it. This means that you can take small-moderate amounts regularly to reap the benefits of vitamin D. Supplementation with 1000 IU of vitamin D is a good starting point for most people.



There are a few reasons to take a probiotic supplement during cold & flu season. Probiotics work for the immune system by strengthening the intestinal walls, and combating harmful bacteria and pathogens in the gut. They also have been shown to activate both the innate and adaptive immune systems by modulating immune cell actions (3). 


In addition to taking a probiotic supplement, consuming probiotic foods in the diet is wise. These include:

  • Fermented vegetables like sauerkraut, kimchi, fermented beets, etc
  • Kombucha and fermented beverages
  • Yogurts (grass-fed, organic)



This mineral is very important in maintaining a healthy immune system, as well as numerous other important bodily functions. With illness, it helps to reduce inflammation and help immune cells properly function (4). Though long term supplementation is not recommended unless a deficiency is present (shown through bloodwork), zinc can be used short-term to improve immunity and combat infections in the form of a capsule, a lozenge, etc.  Zinc is plentiful in the following foods:

  • Raw, unseasoned nuts and seeds like hemp seeds, pumpkin seeds, almonds
  • Wild shellfish and seafood, as well as beef, poultry, and pork
  • Whole grains and legumes


What to Eat when You’re Sick

Food and herbs should be the first line of defense against a minor illness like a cold or the flu. 

  • Bone broth: grandma’s chicken soup is comforting for a reason. Bone broth is rich in minerals, palatable when sick, and strengthens the gut.
  • Easy-to-digest foods like oatmeal, with warming spices like turmeric and ginger
  • Complex carbohydrates to restore energy like sweet potatoes, rice, bananas, etc. Choose organic foods and whole grains when possible.
  • Restore electrolytes, especially if vomiting and/or diarrhea is an issue, with coconut water
  • Herbal teas and tinctures: some of these can be taken at the onset of illness, and others can be consumed regularly throughout cold and flu season to prevent illness. Have a teaspoon of raw honey in your tea for further antibacterial and throat-coating actions. Dosages of herbs will differ between children and adults so it’s best to consult a herbalist or holistic nutritionist to check that the herbs are safe for children and what dosage is best. Herbs can also be passed through breast milk for babies. Consider keeping the following herbs in your home apothecary, which are all safe for children over the age of 3:
    • Echinacea tea is great for stimulating the immune system to fight a virus or bacterial infection (not to be used for those with autoimmunity)
    • Astragalus is a helpful herb to take throughout cold & flu season to regulate and strengthen the immune system (great when taken as a tincture)
    • Peppermint and licorice root teas for respiratory illness
    • Catnip tea to break a fever (also a mild sedative)
    • Peppermint and dandelion tea for diarrhea or digestive illnesses
    • Elderberry syrup, Marshmallow root and licorice root teas help to coat the throat during a cough (especially good for dry cough).  One particular brand that we find works well is Genestra’s English Ivy Cough and Cold.  For children there is a kids formula.

To brew a cup of herbal tea, cover the mug for 15 minutes after pouring in hot water. This allows for oils released by the herbs to remain in your cup – allowing you to get a stronger herbal medicine.


While most people can benefit from these supplements and herbs during illness, bio-individuality must be taken into account especially when it comes to chronic health conditions, allergies, etc. Contact Nutrition Dispensary today to discuss personal strategies for you and your family to combat cold & flu season! 

Blog Written by:  Jennifer Costello

January 2023, Nutrition Dispensary Inc.


Advice and/or information provided is not intended to diagnose, cure, treat or prevent disease.

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