Carol blog - Jan

By Carol Harrison, RD 

Cold and flu season is here, and your clients may be looking to improve their immunity. Regular exercise supports optimal immune health, but your clients are likely also interested in how to ramp up their defenses with good nutrition.  

Reality Check: Health Canada reports that nearly half (~46 per cent) of calories consumed by Canadians come from calorie-rich, nutrient-poor, ultra-processed foods such as sweet drinks, baked goods, frozen pizza and hot dogs. Helping your clients to replace these with a wide variety of nutrient-rich foods such as vegetables, fruits, pulses, whole grains, nuts, fatty fish, beef, poultry, dairy and eggs is likely the best way to support immune health through better nutrition.  

What to eat for better immune health  

Science backs the role of good nutrition in supporting our immunity. Without the right nutrients, the immune system can’t work as intended.  

Below are some of the top nutrients known to support immune health, along with food sources for each.  

Nutrient  Role*  Food Sources  
Protein  Needed to build antibodies to fight infections. Beef, fish, eggs, tofu, beans, lentils, poultry, nuts, seeds 
B vitamins Many Canadians are short on B vitamins Help to keep the gut barrier intact, limiting pathogens from entering the body. B6: Chickpeas, beef, salmon, poultry, fortified cereals B12: Salmon, clams, beef, milk, eggs, poultry, fortified nutritional yeast  
Zinc  30%–34% of women and 21%–44% of men (depending on age group) do not get enough dietary zinc.  Too little zinc reduces the number of immune precursor cells and reduces good “killer cell” activity. Beef, pork, baked beans, fortified breakfast cereals, pumpkin seeds, dark poultry meat, yogurt  
Vitamin C 28%–59% of women and 38%–64% of men (depending on age group) do not get enough dietary vitamin C.  Supports antibody production and movement of white blood cells to sites of infection.  Red peppers, citrus fruits, kiwi, broccoli, strawberries, cabbage, tomatoes, Brussels sprouts 
Vitamin A  47% of women and 51% of men 19+ years do not get enough dietary vitamin A.  Supports immune cells to mature and function properly. Not enough vitamin A can reduce good “killer cell” capacity. Dark green or orange produce (sweet potatoes, carrots, mangos, spinach), herring, milk, cheese, eggs 
Vitamin D** Almost all Canadian adults—98% of women and 94% of men—do not get enough vitamin D. Supports antimicrobial activity. Trout, salmon, mushrooms, fortified cow/soy/almond/oat milk, (sunshine alone is not a reliable source)  
Selenium  Low selenium reduces good “killer cell” activity and increases our susceptibility to infection. Beef liver, oysters, potatoes, shiitake mushrooms, cashews, sunflower seeds, tofu  
Vitamin E  Supports antibody production  Nuts, seeds, nut butters  
Iron  Nearly 30% of women aged 19–50 do not get enough dietary iron.  In adequate amounts, iron helps to reduce the risk of infection.  Beef, lentils, white beans, tofu, sardines, cashew nuts, chickpeas, fortified grains (pasta, cereal, bread) Note: animal sources of iron such as meat are far better absorbed than the iron from plant sources. 
DHA and EPA   These omega-3 fats support healing and reduce inflammation.  Salmon, mackerel, tuna, herring, sardines and fortified foods (eggs, dairy, juice) 

*Most nutrients play many more roles in optimizing our immune health. 

**For those over 50 years old, Health Canada recommends a daily vitamin D supplement of 400 IU (equivalent to 10 µg). 

What about gut health?  

Creating and maintaining a healthy gut microbiota—the microorganisms that live in our digestive systems—also helps to support the immune system and fight off illnesses.  

Encourage your clients to eat a nutritious diet that includes a variety of fibre-rich and fermented foods. Healthy fermented foods to try: kefir, yogurt, kimchi, sauerkraut, tempeh, and kombucha. 

Keep the message simple  

Optimizing immune health through good nutrition comes down to creating healthy dietary patterns built around eating a wide variety of animal and plant-based, nutrient-rich foods—no one food or single supplement can make up for a poor diet. Consider sharing these nutrient-rich meal ideas as a practical way to help clients get the good nutrition they need to support a healthy immune system.  

3 easy dinners packed with nutrients to support immune health  

  1. Sheet pan dinner with salmon, cherry tomatoes, and green beans. 
  1. Stir-fry packed with veggies and beef. 
  1. Stuffed Peppers with quinoa, beans, and corn. 

Read more tips on promoting nutrient-dense food choices


Carol Harrison is a registered dietician who loves her daily workouts! She has a food nutrition communications company in Toronto. For more dinner inspiration and meal planning tips, follow Carol on Instagram and Twitter @CarolHarrison.RD