Part III: Foods and Supplements That Boost Immune Health


Written by Eileen Henderson, RDN, LD (GemCare Wellness)

Written by Chelsea Jackie, MFN, RDN, LD, CPT (GemCare Wellness)


Can taking supplements replace eating fruits and vegetables while preventing illness?


Supplements can help with correcting nutritional deficiencies and provide additional immune support, but they cannot keep someone from getting sick. Studies show a diet high in processed foods and sugar actually suppress the immune system. A balanced diet rich in whole foods that provide protein, fiber, vitamins, antioxidants, and probiotics, actually help the body heal, repair, and fight back against infection. Let’s take a look at key nutrients in the form of foods and supplements that help boost the immune system.



Foods That Support Your Immune System

Protein helps the body heal and recover, which plays an important role in the body’s immune system. It is recommended to eat at least 0.36 - 0.45 grams of protein per pound of your body weight daily. Thus, if you are an individual who weighs 140 lbs., your daily protein need would be 50 grams to 63 grams of protein per day (140 x 0.36 gm to 140 x 0.45 gm).

Food sources: chicken, fish, eggs, Greek yogurt, nuts, and cheese.


Fruits and vegetables are high in vitamin A, vitamin C, fiber, and antioxidants that support the immune system. It is recommended to eat 5 - 9 servings of fruits and vegetables each day (a serving is ½ cup).

Food sources: Vegetables include leafy greens, broccoli, cauliflower, carrots, asparagus, sweet potatoes, and more. Fruits include strawberries, blueberries, apples, and oranges, among many others!


Fermented foods provide probiotics that are naturally made with an ancient food preservation process. Probiotics are beneficial bacteria that positively impact digestive health and the immune system. It is important to pair fermented foods with prebiotic-rich foods (e.g. bananas, flaxseed, asparagus, and garlic).

Food sources: kombucha, kefir, kimchi, sauerkraut, naturally fermented pickles, and other fermented vegetables.



Supplements That Support Your Immune System

Multivitamins provide vitamins and minerals that help cover the body's basic needs.


Probiotics are beneficial bacteria that have been shown to positively impact the balance of bacteria in the digestive tract and create a barrier against germs which support the immune system. Look for brands that contain at least 5 billion cultures and lactobacillus plantarum or spore forms of bacillus to provide additional benefit for the immune system.


Fish oil contain high levels of omega-3 and have been shown to help reduce inflammation and the risk of chronic disease. Look for a supplement that lists at least 500mg of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).


Vitamin D3 strengthens the immune system by triggering a response to fight off bacteria and viruses. Studies have shown that people with vitamin D deficiency are 11 times more likely to get a cold or the flu, and supplementing with vitamin D can reduce colds and flu by 42%. The recommend dietary allowance (RDA) for vitamin D is 600 International Units (IU) for men and women and 800 IU for adults over the age of 70. It is difficult to get enough vitamin D from the diet and vitamin D requires some dietary fat for absorption. The body can also make adequate vitamin D when exposed to UV rays from the sun for 10-30 minutes 3 times per week, but the weather conditions must be right (season, time of day, where you live, cloud cover, pollution affect the amount of UVB that reaches your skin). It is also important not to overdose on direct sunlight and wear sunscreen. In the winter months, it can be difficult to get enough sun exposure and vitamin D supplements are typically recommended.


Vitamin C is an antioxidant that fights free radicals (unstable atoms that cause cell damage and illness) and stimulates the formation of antibodies which support the immune system. However, research does not consistently show that vitamin C supplementation prevents the common cold. It is recommended to get vitamin C from whole foods, because foods contain other important nutrients. Eating five servings of fruits and vegetables each day, will provide adequate vitamin C. If taking a supplement, look for vitamin C that can be taken in smaller doses throughout the day.


Zinc helps the body with growth, development, and maintenance of immune function. Studies have shown that zinc-deficient populations have an increased risk of acquiring viral infections. Other research shows that zinc administered within 24 hours of cold symptoms reduces the duration of common cold symptoms in healthy people. The recommended daily amount of zinc for women is 8mg per day and 11mg per day for men. Look for zinc citrate, which is easier for the body to absorb and less likely to cause stomach irritation.



It is important to consult with your doctor or dietitian before adding a supplement, especially if you are already taking other supplements or medications. Some supplements can have an additive effect or interactions. Supplements can play a part to support our immune system, but it is also important to prioritize eating nutritious foods. Whole foods offer key nutrients for immunity, while also delivering a broad spectrum of other nutrients and are enjoyable to eat!


Would you like to learn more about how you can support your own immunity and create your own personal diet plan complete with immune-boosting properties? The GemCare Wellness Registered Dietitians are here to help. To learn more about NutraVantage one-on-one nutrition counseling services, please visit our website. We would love to work with you!



Disclaimer: The information contained here within is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health providers with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read.

If you think you may have a medical emergency, call your doctor, go to the emergency department, or call 911 immediately. GemCare Wellness (GCW) does not recommend or endorse any specific tests, physicians, products, procedures, opinions, or other information that may be mentioned here within. Reliance on any information provided by GCW, GCW employees, contracted writers, or medical professionals presenting content for publication here within is solely at your own risk.

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