Saturday, March 28, 2020

Food and Immune Health

By Dr. Iva Lloyd, ND

What you eat truly is the foundation of overall health.  But, choosing the ideal diet can be challenging as the "right diet" can vary based on age, health status, food intolerances and other factors.

This current health crisis is reinforcing the need for a healthy diet as the health of your immune system is strongly linked to what you eat and what you don't eat.  When looking at diet from the lens of immune health it can be helpful to increase foods that support immune function and ensure adequate hydration, and to limit foods that cause inflammation or that impede immune function.


The following is a general guide. For recommendations specific to you or your family members it is always best to work with your naturopathic doctor.

General "Rules"

Although there is not one diet that is best for everyone, here are some general "rules" to keep in mind:
  1. Eat primarily to be healthy
  2. Eat from all the food groups
  3. Ensure proper portions. 
  4. Eat regular meals.
  5. 75% whole foods 
To learn more about these general rules, check out our blog Nutrition - Top 5 Things to Remember.

Foods That Support Immune Function

A balanced diet is essential to proper immune function. The following is an overview of the nutrients that are required for the immune system to work properly and the foods that contain them:
  • Vitamin C: blackcurrant, broccoli, citrus fruits, kale, parsley, spinach
  • Vitamin A: carrots, sweet potatoes, spinach, chicory, dill, dried apricots, egg yolk, kale, liver, parsley, red pepper.
  • Vitamin B6: avocados, walnuts, spinach, nuts and seeds, whole grains
  • Vitamin B12: beef, poultry, fish, dairy, sauerkraut, seaweed
  • Vitamin D: butter, dairy, eggs, liver, sardines, mackerel, oatmeal, oysters, salmon, shitake, sprouts, sweet potatoes, tuna
  • Omega 3 oils: fish such as sardine, mackeral, salmon and tuna, almonds, avocado, beans, chia seeds, linseeds, olive oil, spinach, walnuts
  • Folic Acid: dark leafy greens, asparagus, broccoli, citrus fruit, dried beans, peas, whole grains.
  • Copper: liver, oysters, cashews, soy beans, dark leafy greens, avocados, kale, linseeds, pumpkin seeds, walnuts, brazil nuts, pistachios, pine nuts, legumes, dried fruits
  • Zinc: oysters, seafood, pumpkin seeds, beef, chicken, cashews, brazil nuts, oatmeal, sunflower seeds, hazel nuts and whole grains.
Nutrient deficiencies are a global problem.  Research indicates that deficiency in nutrients impairs immune function, contributes to chronic disease and increases the risk of mortality.  Health and longevity is strongly correlated with overall nutritional status.

Foods That Contribute to Inflammation

When the immune system is overwhelmed it creates inflammation. This inflammation can often do more damage than the pathogen or toxin that it is trying to protect the body from.  Avoiding foods that add to the inflammatory process, especially if you have respiratory symptoms such as cough, shortness of breath or fatigue, will assist you recovery.  The following strategies will help limit the amount of inflammation due to food:
  • If you have known food intolerances, it is recommended to limit these as much as possible.
  • Limit refined carbohydrates such as white bread, pastries, cookies, white rice and other "white" highly processed foods.
  • Avoid trans fats, vegetable oils and foods high in sugar.
  • If you have mucous-related symptoms limit dairy, wheat, yeast and bananas. Fruit is healthy, but it is important to limit your fruit intake to a couple servings a day.

Stay Hydrated

Ensuring regular hydration is an important aspect of immune health.  The following foods can help ensure adequate hydration:
  • Water. Drink about 1/2 your body weight in ounces a day.
  • Herbal teas are a great alternative. There are a number of herbal teas that also support immune and respiratory health.
  • Green drinks and diluted vegetables juices can be beneficial as long as the sugar content is minimized.
For more information, check out our blog on Water - Top 5 Things to Remember.

Foods That Might Weaken Immune Function

There are some foods and drinks that impede immune health. To ensure that your immune system stays strong limit the following foods:
  • Sugar. The consumption of refined glucose, fructose, sucrose, honey, pop and high-sugar juices, has been shown to compromise the immune system for three to five hours. The most important thing you can do when you are sick or when you are concerned about your immune system is to stay away from all processed sugar.
Salt.  Avoid high-salt foods such as processed meats, and packaged soups and foods. Salt adds to the inflammatory response and weakens overall immunity.
  • Junk Food. Most people enjoy a bit of junk food every now and then, but it is important to limit it or avoid it completely when working on strengthening overall immune health. Junk food is generally nutrient deficient, high in salt and/or sugar and high in food additives.
Eating healthy is pretty straight forward it you have a lot of variety and ensure that the majority of food that you eat is whole food.

If you would like any guidance on what is best to eat for you or your family, please work with one of our naturopathic doctors.