Food for Thought: Immune-boosting foods

Many of us are trying to get through this year’s cold season without a sneeze or a cough. We go through our days washing our hands, and trying to fight away the unwanted germs. 

But what about starting from the inside out? There are many types of foods that can be incorporated into your diet to help build your immune system so that you can be better prepared -- and that can start with your grocery list. 

So, what exactly do you need to look for? Focus on foods containing antioxidants and probiotics. Both of these can exhibit beneficial effects on the immune system.

Antioxidants

Antioxidants help maintain a strong immune system by fighting off free radicals, which can harm our cells. By maintaining the integrity and structure of our cells, we can be less susceptible to getting sick. Antioxidants are found in our food through vitamins including vitamin A, C, and E.

• Vitamin A: This antioxidant source helps your cells to react properly to those unwanted germs that cause you to get sick. You can find vitamin A in a variety of foods that you may already be consuming. These foods include dark leafy vegetables, red and orange fruits, milk, eggs and fish. The recommended amount of vitamin A to be consumed by adults aged 19 years or older is 10,000 IU per day.
  
  
• Vitamin C: Vitamin C is another antioxidant that can help build your immune system. This vitamin acts to support our immune system through enhancing the body’s protective barrier against infectious agents. Fruits and vegetables that contain vitamin C include: citrus fruits, strawberries, tomatoes, and broccoli. The recommendations for vitamin C do vary between men and women. It is recommended that adult men should consume around 90 mg per day and adult women should consume around 75 mg per day.
  
  
• Vitamin E: Vitamin E is a valuable antioxidant that aids in fighting infection and preventing oxidative stress that results in ideal immune function. If you are trying to find sources of food high in vitamin E, start with nuts and seeds including almonds, sunflower seeds, and peanuts.  Natural forms of vitamin E can also be found in vegetables such as spinach, broccoli, and vegetable-based oils. Many foods also have vitamin E added into them to make them more nutritious, including fortified breakfast cereals. It is recommended for adults to consume around 15 mg per day of vitamin E.

Probiotics

Probiotics would be the second thing to incorporate in your diet. Probiotics are a form of bacteria that, when consumed, help maintain the good bacteria in our gut. They strengthen the immune system by decreasing inflammation, enhancing our defense mechanisms, and preventing the pathogens negative effects. Sources of probiotics include yogurt, kefir, sauerkraut, kimchi, kombucha, and many other fermented foods. One important thing to look for on the food label when searching for a probiotic- rich yogurt is the phrase “contains live and active cultures.” This tells us that probiotic bacteria is present.

Immune-boosting snacks

By adding these foods into your diet, you can begin to build your immune system and fight your way through the cold season.

• Probiotic-rich yogurt with almonds
• Hard-boiled eggs with an orange
• Raw broccoli and tomatoes with homemade ranch dip made out of probiotic-rich plain Greek yogurt
• A smoothie made with probiotic-rich yogurt, spinach, milk, and your choice of fruit
• Vitamin-E-fortified cereal with milk

This post was written by Amanda Martin and Brooke Crotty. Amanda is in the Dietetic Internship program and Brooke is a first-year graduate student in the Nutrition Diagnostics Master's Program and Dietetic Internship.

References 

Bendich, A. (n.d.). Vitamin E and immune functions. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/3074789

Carr, A. C., & Maggini, S. (2017, November 03). Vitamin C and Immune Function. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/29099763

Hajian, S. (2014, November 17) Positive effect of antioxidants on immune system [PDF]. Immunopathol Persa.

How Vitamin C Supports a Healthy Immune System. (n.d.). Retrieved from https://www.eatright.org/food/vitamins-and-supplements/types-of-vitamins-and-nutrients/how-vitamin-c-supports-a-healthy-immune-system

Huang, Z., Liu,Y., Qi,G., Brand, D., & Zheng, S. G. (2018, September). Role of Vitamin A in the Immune System. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162863/

Knight, J. A. (2000). Review: Free Radicals, Antioxidants, and the Immune System [PDF]. Retrieved from http://www.annclinlabsci.org/content/30/2/145.full.pdf

Natural Food Sources of Vitamin A and Provitamin A. (n.d.). Retrieved from https://journals.sagepub.com/doi/abs/10.1177/156482659201400115

Office of Dietary Supplements - Vitamin A. (n.d.). Retrieved from https://ods.od.nih.gov/factsheets/VitaminA-Consumer/

Office of Dietary Supplements - Vitamin C. (n.d.). Retrieved from https://ods.od.nih.gov/factsheets/VitaminC-Consumer/

Office of Dietary Supplements - Vitamin E. (n.d.). Retrieved from https://ods.od.nih.gov/factsheets/vitamine-consumer/

Probiotics: How should they be defined? (1999, October 05). Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S0924224499000278

Yan, F., & Polk, D. B. (2014). Probiotics and immune health. NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4006993/