The question, “What should I eat to support my immune system?” can be answered with one big word that describes a very small dietary element: micronutrients.
Micronutrients play an important role in supporting your immune system. And hey, if a healthier immune system means not missing out on time in the gym or with family and friends and spending less time in the medicine aisle of the grocery store, it’s worth prioritizing, right?
Learning how vitamins and minerals can support your health could be the difference between being the person who gets sick every year and sailing through cold and flu seasons with no problem.
So, let’s (literally) start small and build from there so you feel equipped to keep your body as healthy as possible.
What are Micronutrients?
When you hear “micronutrients” you probably think of vitamins first.
Maybe your doctor recommended that you take a daily multivitamin or maybe you heard a coworker say they’re getting their “daily dose of vitamin D” after eating lunch outside.
Micronutrients include the vitamins and minerals that your body needs in small amounts.
(If you’re thinking, “Wait, what about macronutrients?” check out the WAG Nutrition Guide!)
What are Vitamins?
Vitamins are organic substances (made by plants or animals). They’re further broken down into two categories: fat-soluble and water-soluble
Fat-soluble vitamins are best absorbed when eaten with a healthy fat source. They’re then stored in your body fat and liver. Fat-soluble vitamins, such as A, D, E, and K can be used later since they are stored in the body.
Water-soluble vitamins dissolve in water. Some examples of water-soluble vitamins include C and B vitamins. They travel through your bloodstream and exit your body more quickly, typically through urine. Because water-soluble vitamins can’t be stored, it is even more important that your body replenish them.
What are Minerals?
Minerals are inorganic elements made from soil or water and absorbed by plants or consumed by animals .
There are also two types of minerals: macrominerals and trace minerals.
Your body needs macrominerals such as calcium, magnesium, and sodium in larger amounts and trace minerals like zinc and iron in smaller amounts. Minerals are important for numerous functions in the body including enzyme and hormone production, turning food into energy, bone strength, and brain operations .
Micronutrients are essential for development, well-being, and disease prevention . There are approximately 30 vitamins and minerals that your body does not produce naturally but still needs in order to stay healthy . Since your body cannot manufacture micronutrients in sufficient amounts on its own, most micronutrients come from your diet .
Wait, did I say thirty micronutrients?!
Don’t worry, in this article we’re only focusing on eight of the most important micronutrients to your immune system: vitamins A, B6, B12, C, D, and E and the minerals zinc and magnesium.
Before we dive into which vitamins and minerals do what, let’s take a crash course on the immune system.
How Does the Immune System Work?
Before we can dive into how micronutrients support the immune system, we have to back it up and answer the question, “How does the immune system work?”
It’s okay if the last time you thought about the immune system was before a high school science test. We’re giving you a brief overview of the immune system and its two types of immunity: innate and adaptive.
The Immune System 101: Innate Immunity
“Innate immunity” refers to the part of your immune system you were born with. It Includes physical and biochemical barriers and immune cells . These are your body’s first line of defense against germs.
Physical barriers keep germs from entering your body and include:
- Body hair
- Mucous membranes (the inner lining of some organs and body cavities like the ears, nose, and throat)
If germs break the physical barriers it becomes the job of biochemical barriers to keep the bacteria from gaining a further foothold. Some biochemical barriers include:
Biochemical barriers are harder to visualize so here is a quick example: Your stomach has a naturally low pH level which makes it inhospitable for those threatening microorganisms that may be ingested .
When physical and biochemical barriers are infiltrated, immune cells help stop bacteria and viruses that enter the body. Your immune system has a special type of white blood cell called scavenger cells (or phagocytes). These cells essentially “eat” germs which neutralize them until the adaptive immune system kicks in.
Natural killer cells (lymphocytes) are another type of white blood cell that plays an important role in the innate immune system. They search for cells that are infected and then kill their surface with cell toxins .
The innate immune system is fast-acting . If you get a papercut and bacteria makes its way into the wound your innate immune system detects and kills that bacteria within hours.
Your innate immunity, sometimes called “nonspecific immunity”, responds to all germs and foreign substances in the same way. That is where the next type of immunity comes into play.
The Immune System 101: Adaptive Immunity
Your adaptive immune system is made up of B cells, T cells, and antibodies. It kicks in when your innate immune system is not able to destroy the germs on its own.
Adaptive immunity takes longer than innate immunity because it identifies and then targets a specific type of germ . The adaptive immune system has to figure out what the germ is before it can respond.
T cells and B cells are the white blood cells in charge of this determination. Once activated, B cells produce antibodies that attach themselves to the cell surfaces of bacteria and viruses. This prevents the bacteria and virus cells from attaching to and infecting the normal cells in your body.
Even though it is slower (sometimes taking a few days to kick in) the adaptive immune system is more accurate. Your adaptive immune system can also remember germs, which can speed up future responses when your body is exposed to a previous infection .
How do Micronutrients Support the Immune System?
That’s the big question, right? If you know that micronutrients are some of the best things to eat to keep your immune system strong, the next question is “How do micronutrients support the immune system, anyway?”
Every part of the immune response relies on certain vitamins and minerals to function properly and efficiently. Here’s a quick, simplified breakdown:
- Maintains the integrity of physical barriers (such as skin)
- Contributes to antibody production
- Helps with the growth and production of B cells [8, 9]
- Aids in wound healing which is important since skin is part of the first line of defense in innate immunity
- Contributes to antibody production, enhances T-cell function 
- Increases the number of T cells 
- Contributes to antibody production 
- Aids in maturation and multiplication of white blood cells which includes natural killer cells, T cells, and B cells 
- Maintains integrity of physical barriers
- Enhances white blood cell production and function [8, 9]
- Stimulates production of antibodies 
- Offers protection to immune cells from oxidative stress 
- Monitors antibody production while keeping the body from producing an excessive amount
- Helps with the regulation of the inflammatory response from T cells 
- Supports the integrity of physical barriers
- Enhances natural killer cells 
- One of the most effective nutrients known to support the immune system’s function 
- Manages inflammatory response
- Reduces oxidative stress 
- Helps wounds to heal (important for keeping that skin as an effective physical barrier)
- Improves natural killer cell activity
- Increases cell growth and division 
- Decreases oxidative stress
- Limits inflammatory response [8[
- Can shorten the duration of symptoms once you are sick 
Science class dismissed!
What to Eat to Strengthen Your Immune System
You might be thinking, “Great, now I know how the immune system works and how each micronutrient supports it. But what does all this mean for me?”
Remember, your body does not produce the amounts of micronutrients that it needs on its own so you must get them from other sources.
It is ideal to meet your micronutrients needs by eating whole foods rather than by taking supplements . So where can you find each vitamin and mineral crucial to immunity? And how much should you consume each day? Check out the table below!
Chances are, you already eat a lot of the foods listed here. Isn’t this great news?! You can boost your immune system just by eating foods that are rich in micronutrients. And while you are at it, why not pair eating whole foods with drinking more water and getting quality sleep for the ultimate disease defense?
You can forget the trip to the drug store and start taking the cheapest medicine around - FOOD!
The bottom line is that micronutrients, although needed in small amounts, can make a significant difference in your health, and not just in terms of fighting sickness!
How do Micronutrients Fit into Your Nutrition and Fitness Goals?
We started out small, so now let’s think big: How do micronutrients fit into your health and nutrition goals?
In the new version of the nutrition pyramid, micronutrients are one of the higher-level building blocks to achieving nutrition growth and success. While “if it fits your (IIFY) macros” is important to reach first, IIFY micros is your next order of business when you are looking to optimize your progress and performance.
Like macronutrients, there is not a one size fits all approach to micronutrients. Here are a few ways this may need to be individualized:
Sleep and Stress
Inadequate sleep and/or higher stress can increase oxidative stress levels which also increases your need for antioxidants like vitamins C and E and magnesium.
Location and Temperature
If you sweat a lot, you lose zinc and magnesium at a faster rate and may need to replenish these minerals more readily through diet .
Vegetarians need up to 50% more zinc than meat-eaters as meat provides a good source of zinc. Vegetarian diets are also typically higher in grains and beans which contain compounds that prevent zinc from getting fully absorbed by the body .
Training Frequency and Intensity
Micronutrients play a crucial part in energy production and recovery . Antioxidants like vitamins A, C, and E protect against oxidative damage which may be induced by vigorous training. These micronutrients can reduce muscle soreness post-exercise. Vitamin D plays a role in protein synthesis (hello muscle growth!) and vitamin B6 and B12 are involved in energy production and repair, respectively .
Research shows that eating less than recommended amounts of vitamins and minerals contributes to illnesses like heart disease, type 2 diabetes, cancer, and osteoporosis . So, it is not just the question of “What should I eat to support my immune system?”, but also, “what should I eat to feel my best long-term?”
These are just some examples of how micronutrient needs can vary by lifestyle and goal. This is where a nutrition coach can help you determine what is right for YOU.
Consuming the right amounts of micronutrients for your body, lifestyle, and goals is not only important for keeping you healthy during cold and flu season but it is important to consider for your long-term health as well.
- Harvard T.H. Chan School of Public Health (2021). Vitamins and minerals. https://www.hsph.harvard.edu/nutritionsource/vitamins/
- United States National Library of Medicine (2021, September 23). Minerals. https://medlineplus.gov/minerals.html
- Centers for Disease Control and Prevention (2021, June 28). Micronutrient facts. https://www.cdc.gov/nutrition/micronutrient-malnutrition/micronutrients/index.html
- Merz, B. (2021, February 15). Micronutrients have major impact on health. Harvard Health Publishing, Harvard Medical School. https://www.health.harvard.edu/staying-healthy/micronutrients-have-major-impact-on-health
- Institute for Quality and Efficiency in Health Care (2020 July 30). The innate and adaptive immune systems. https://www.ncbi.nlm.nih.gov/books/NBK279396/
- Erickson, K. L., Medina, E. A., & Hubbard, N. E. (2000) Micronutrients and innate immunity, The Journal of Infectious Diseases, 182, S5–S10, https://doi.org/10.1086/315922
- Gombart, A. F., Pierre, A., & Maggini, S. (2020). A review of micronutrients and the immune system-working in harmony to reduce the risk of infection. Nutrients, 12(1), 236–277. https://doi.org/10.3390/nu12010236
- Pecora, F., Persico, F., Argentiero, A., Neglia, C., & Esposito, S. (2020). The role of micronutrients in support of the immune response against viral infections. Nutrients,12(10):3198. doi: 10.3390/nu12103198.
- Alpert, P. T. (2017). The role of vitamins and minerals on the immune system. Home Health Care Management & Practice, 29(3), 199–202. https://doi.org/10.1177/1084822317713300
- Lewis, E. D., Meydani, S. N., & Wu, D. (2019). Regulatory role of vitamin E in the immune system and inflammation. IUBMB life, 71(4), 487–494. https://doi.org/10.1002/iub.1976
- Brilla, L. R. (2012). Magnesium influence on stress and immune function in exercise. Journal of Sports Medicine & Doping Studies, 2:3. DOI: 10.4172/2161-0673.1000111
- National Institutes of Health (n.d.). Dietary supplement fact sheets. https://ods.od.nih.gov/factsheets/list-all/
- Rodriguez, N. R., DiMarco, N. M., & Langley, S. (2009). Position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and athletic performance. Journal of the American Dietetic Association, 109(3), 509–527. https://doi.org/10.1016/j.jada.2009.01.005