5 Foods that Boost Immunity and May Help Prevent Colds and Flu

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Cold and flu season is upon us and as the old adage goes, “An ounce of prevention is worth a pound of cure.” We all know that it is much better to avoid getting sick than to try to shake a bug once it has taken hold. Unfortunately, even with the best personal hygiene, such as frequent hand washing, it can be difficult to avoid germs. That is why it is so important to have a strong immune system.

The immune system is made up of cells and proteins that fight off foreign invaders like viruses and bacteria and prevent infection. These cells work together as a team and they have a long memory. Ideally this coordinated defense prevents an illness before it takes hold. But even if you do get sick, the immune system remembers the virus and can fight it off more effectively in the future. Luckily for us, diet has a big impact on immune function, and optimizing nutrition is one of the most important things we can do to boost our defenses.

Here are five foods or food groups that benefit the immune system.

Chicken soup with egg noodles. Photo: Wendy Goodfriend
Chicken soup with egg noodles. Photo: Wendy Goodfriend

Chicken soup and other foods high in protein

Grandma was right, high quality complete proteins are essential for the immune system to function. The truth is that all of our immune cells and antibodies are made up primarily of proteins. When we don’t get enough dietary protein or we are unable to absorb the protein from our diets the immune system suffers. The nice thing about chicken soup is that it is both a complete protein, meaning that it contains all of the essential amino acids, and it is easy to digest because the meat has been cooked until it is soft and falling apart. However vegetarians and chicken soup haters need not despair, all high protein foods are helpful. Meat, eggs and beans are also good sources.

Maitake mushroom surrounded by Trumpet and button mushrooms. Photo: Wendy Goodfriend
Maitake mushroom surrounded by Trumpet and button mushrooms. Photo: Wendy Goodfriend

Medicinal mushrooms

Many medicinal mushrooms are also edible and delicious. They can be sauté roasted and added to soups or gravies, but they should not be eaten raw. Shiitake and Maitake mushrooms are commonly available at stores and farmers markets around the Bay Area. These fungi are immune super foods with properties ranging from increasing white blood cell numbers to supporting anticancer effects. Most people agree that the medicinal components of these mushrooms are best absorbed when they are extracted in hot water. This means that soups or teas are the ideal way to eat them. In fact certain mushrooms like Reishi are so hard and woody that they cannot be eaten directly but are commonly simmered in broth and then removed. However they are prepared, mushrooms add both health benefits and a rich, savory flavor to any dish.

Tangerines, Cara cara and navel oranges. Photo: Wendy Goodfriend
Tangerines, Cara cara and navel oranges. Photo: Wendy Goodfriend

Tangerines, kiwis and other foods high in vitamin C

Vitamin C is a powerful immune tonic. It increases white blood cell numbers and improves the function of these important immune cells.


It is an essential nutrient meaning that humans cannot make their own; they must consume it in food or supplements. It is best absorbed in small frequent doses, which is easy to do this time of year when oranges, tangerines and kiwis abound. Vitamin C is heat sensitive, and it can be destroyed by cooking. The best way to eat foods rich in vitamin C is fresh and raw.

Heads of Garlic. Photo: Wendy Goodfriend
Heads of Garlic. Photo: Wendy Goodfriend


We often use garlic for colds and flus because it has direct anti-viral properties. But garlic is also a potent regulator of the immune system. Garlic doesn’t just stimulate immune cells it also reduces inappropriate inflammation so the immune system can focus on the real invaders. For its antimicrobial properties garlic must be consumed raw and freshly crushed. For example fresh, crushed garlic can be mixed with honey for sore throats. But for immune balancing, dried and aged extracts have been frequently researched. Based on those studies, soups, sautés and sauces should all be beneficial.

Raw Khitchari Kraut and organic yogurt. Photo: Wendy Goodfriend
Raw Khitchari Kraut and organic yogurt. Photo: Wendy Goodfriend

Yogurt, Sauerkraut and other cultured foods

We are not sterile creatures. There are bacteria that populate our skin, nasal passages, genitalia and most importantly our gastrointestinal tract. We are coming to realize that the difference between having the right bacteria in our guts and the wrong bacteria can be the difference between health and disease. That is why beneficial bacteria (AKA probiotics) are so important in the human diet. These probiotics don’t just improve the health of the gut. They directly improve gut and systemic immunity. One of the best ways to consume probiotics is in cultured foods such as yogurt, kefir, sauerkraut, and miso. Because these beneficial foods contain live bacteria and yeast they should not be cooked or excessively heated.

Below is one of my favorite warming winter soups. It is incredibly delicious with Chantrelle mushrooms. However, Shiitake and or Maitake also give it a lovely flavor with an added immune kick. Be sure to use unpasteurized miso and add it at the end for a live cultured food.

Creamy Mushroom Soup with Fresh Shiitakes

Makes 6-8 servings

  • 1 medium onion diced
  • 2 cloves of garlic, peeled and minced
  • 4 cups of shiitake mushrooms, stems removed and sliced (you may use other mushrooms if desired such as maitake or oyster)
  • 3 tablespoons of extra virgin olive oil
  • 1 teaspoon salt
  • 6 cups of water
  • 1 cup of cashews
  • 2 tablespoons of chickpea miso
  1. Heat the olive oil in a heavy bottom stockpot. Add the onion and sauté it over medium-low heat for 5 minutes or until it begins to brown. Stir it frequently to prevent it from burning.
  2. Add the garlic and continue to sauté for 1 minute stirring frequently.
  3. Mix in the mushrooms, and sauté for five more minutes.
  4. Add 3 cups of water and 1/2 teaspoon of salt to the pot and stir well, scraping the bottom with a wooden spoon to remove and caramelized vegetables.
  5. Cover the pot and allow it to simmer for 10 minutes.
  6. While the soup is simmering place the cashews and 1 cup of water in a blender. Make sure the lid is secure and start the blender on low, slowly increasing to the highest speed. While blending gradually add 1 more cup of water, 1/4 cup at a time every time the mixture gets too thick to process. You should end up with a smooth cashew cream at the end. In small blenders this often works better in two batches. The cashews will puree more easily if they are presoaked in water to cover overnight. If you do this be sure to drain and rinse them well before making cashew cream.
  7. Pour the cashew cream into the soup pot while stirring and mix it well. Rinse the blender out with 1/2 cup water and add that to the pot as well. The cashew cream will thicken as it comes to a simmer, so stir the soup frequently during this step. Once the cream has thickened and the soup has come back to full simmer, remove it from the heat.
  8. In a small bowl dissolve the miso into the last 1/2 cup of water.
  9. Stir the miso into the soup and taste it. Add the last 1/2 teaspoon of salt if desired.
  10. Serve the soup warm.


* Note: None of the information in this article is intended to diagnose, or treat any disease or health condition.