Woman squeezing lemon half

The human body is a marvelous thing. At this very moment, hundreds of complex processes are occurring within you—you’re producing red blood cells by the millions; your hair and nails are harnessing the protein keratin to grow; your amino acids are repairing body tissue.

All of these processes keep you alive and well—and they happen more or less automatically with materials your body already has.

However, when it comes to your immune system, you may need some external help from vitamins. Your immune system relies on a variety of vitamins to function, and because the body can’t synthesize enough vitamins on its own, it’s vital to find other ways to attain them.

In this guide, we’ll be looking at the five best vitamins to boost your immune system and where to find them.

#1 Vitamin A

One of the most crucial vitamins for your immune system is vitamin A. It comes in several forms known as retinoids:

  • Retinol
  • Retinal
  • Retinoic acid

Along with providing benefits to your vision and growth, vitamin A enhances immune function in the body in various ways, including:1

  • Improving the mechanistic defense of oral mucosa
  • Regulating bone marrow population
  • Reducing inflammation
  • Enhancing humoral immunity

Because vitamin A plays a role in adaptive immunity (immunity that develops as a response to new substances) and in the innate immune system (your “built-in” immunity), it’s essential to satisfy your daily requirements.

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Where to Find Vitamin A

If you’re looking for the best foods to boost your immune system that are also rich in vitamin A, look no further than the produce section. Fruits and veggies full of vitamin A include:2

  • Sweet potatoes
  • Spinach
  • Carrots
  • Cantaloupe
  • Peppers
  • Mangos

Aside from fresh produce, you can find vitamin A in herring, cheese, and fortified milk. Alternatively, you can take vitamin A in the form of supplements.

#2 Vitamin B Complex

While you may think of vitamin B as a standalone nutrient, there are actually eight distinct B vitamins:

  • Vitamin B1 (thiamin)
  • Vitamin B2 (riboflavin)
  • Vitamin B3 (niacin)
  • Vitamin B5 (pantothenic acid)
  • Vitamin B6 (pyridoxine)
  • Vitamin B7 (biotin)
  • Vitamin B9 (folate)
  • Vitamin B12 (cobalamin)

When grouped together, these nutrients make up the vitamin B complex.

Although all of these vitamins play a part in healthy bodily functions, some are more important than others from an immunity standpoint. The B vitamins that may contribute to a strong immune system include:

  • Vitamin B6 – B6 has been shown to increase the production of lymphocytes (the white blood cells that produce antibodies and regulate immune response) in the blood and spleen. Some evidence also shows that a vitamin B6 deficiency can increase the risk of developing cancer.3
  • Vitamin B9 – Also called folate or folic acid, vitamin B9 boosts immunity among many other benefits. Studies have shown that a B9 deficiency can lead to an increase in DNA strand breaks and reduced cell production.3
  • Vitamin B12 – B12 helps regulate some types of immune cells, including certain T cells and natural killer cells.3

B vitamins can also help with stress management, and because stress and immunity are intimately linked, taking them is yet another way to boost your immunity. Learn more about how stress affects the immune system.

Where to Find B Vitamins

Most sources of B vitamins come from animal products—eggs, milk, meats, and fish are all particularly rich in B vitamins.

Still, vegetarians and vegans can find B vitamins in foods like:

  • Tofu
  • Leafy greens (romaine lettuce, spinach, and collard greens)
  • Legumes (beans, lentils, and chickpeas)
  • Peas
  • Mushrooms
  • Avocados
  • Fortified cereals and bread products
  • Nutritional yeast
  • Brown rice

However, to ensure a consistent intake of B vitamins, you may want to turn to an immune defense supplement. For example, our Synergy Vitamin B-12 formula contains the most bioavailable forms of B9 and B12, as well as B6 vitamins.

#3 Vitamin C

Many people will take vitamin C when they start to feel sick. However, taking the recommended amount of vitamin C (100–200mg) every day can keep your immune system strong and protect you from illness.

Taking a vitamin C supplement provides several benefits to the immune system, including:4

  • Acting as an effective antioxidant
  • Enhancing the killing of microbes

Vitamin C can also help wounds heal faster, keeping the body safe from potential infections.

Where to Find Vitamin C

Fortunately, there are all kinds of foods high in vitamin C. You’ll probably encounter most of them on a day-to-day basis, too.

Some of the best sources of vitamin C are:

  • Citrus fruits – Oranges, grapefruits and pomelos are just some of the many delicious sources of vitamin C. And while you probably won’t eat an entire lemon or lime, even a splash of juice from these fruits can provide you with the vitamins you need.
  • Cruciferous vegetables – This category includes broccoli, cabbage, cauliflower, and Brussels sprouts. When eaten raw, these veggies are chock-full of vitamin C. But surprisingly, cooking them further increases their vitamin C content.
  • Elderberries – A cup of elderberries contains around 50% of your daily vitamin C intake,5 and one tablespoon of Elderberry Defense Oil contains 133%.
  • Peppers – When consumed raw, bell peppers deliver a shot of vitamin C to your system. As green peppers are the least ripe, they’re lower in vitamin C. Reach for red or yellow peppers as much as you can. If you can handle the heat, chili peppers are also an excellent choice.
  • Potatoes – Believe it or not, potatoes are also rich in vitamin C. One medium potato contains around 19% of your daily vitamin C intake.6

If these foods aren’t your favorite (or you want a bigger boost of vitamin C), try a vitamin C supplement. We’ve packed ours with vitamins C and E, curcuminoids, bioflavonoids, and bamboo silica.

#4 Vitamin D

Vitamin D regulates the absorption and retention of calcium, so many take it to promote the development of healthy bones and teeth. But the “sunshine vitamin” helps with more than just bone growth.

The immune system benefits from regular intake of vitamin D. The vitamin is essential to your body’s innate antimicrobial response, and it can also modulate the adaptive immune response.7

A vitamin D deficiency can put you at risk of autoimmune diseases, so you’ll want to stock up where you can.

Where to Find Vitamin D

Vitamin D is naturally synthesized in the body when your skin comes in contact with UV-B rays.8 As such, the primary way to take it in is to spend time outdoors in the sun.

With that said, people with vitamin D deficiencies—especially residents of colder, northern regions—may need to take a vitamin D supplement in the winter months to ensure they have a healthy immune system.

The sunshine vitamin occurs naturally in foods like fish, egg yolks, and mushrooms grown in sunlight. Most of the time, however, vitamin D is added to foods, including:

  • Tofu
  • Milk and milk alternatives
  • Breakfast cereals
  • Yogurt
  • Orange juice

#5 Vitamin E

Rounding out the vitamin alphabet is vitamin E—yet another nutrient that keeps the immune system functioning as intended.

In particular, vitamin E appears to help manage and prevent age-related deterioration of inflammatory responses and immunity.9 This boost is likely due to vitamin E’s ability to improve the mediated functions of T cells—a type of white blood cell that’s essential to your body’s immune response.

Vitamin E is also an antioxidant, keeping cells safe from unstable atoms known as free radicals.9 As these atoms are linked to disease and aging, taking a vitamin E supplement helps keep you in peak shape.

Where to Find Vitamin E

While most people are unlikely to be vitamin E deficient, there’s reason to believe that taking more than the recommended daily amount can strengthen the immune system.9 Older individuals are most likely to benefit from taking more of the vitamin, but all populations can take advantage of its effects.

If you’re looking to stock up on vitamin E, consider increasing your intake of these foods:10

  • Nuts and seeds – Snacking on sunflower seeds, almonds, hazelnuts, or peanuts is a fantastic way to add more vitamin E to your diet. Butters made from these foods are also rich in vitamin E.
  • Oils – Vegetable oils made from corn, soybeans, and wheat germ are particularly high in vitamin E. Cooking with sunflower or safflower oils will help increase your daily intake.
  • Fruits and vegetables – Some fruits and veggies contain a moderate amount of vitamin E. The best choices include spinach, broccoli, kiwis and mangos.

You’ll also find vitamin E in the form of dietary supplements. For example, one tablespoon of our Synergy Vitamin C supplement contains 67% of your daily vitamin E value.

Retain Your Vitality With Cymbiotika

Knowing the signs of a weak immune system is essential in order to take action. And one of the best ways to keep your immunity in check is through the regular consumption of vitamins A through E.

While you’ll find many of these nutrients in immunity-boosting foods, turning to dietary supplements guarantees that your body receives the vitamins it needs.

At Cymbiotika, we’ve crafted a range of immunity defense supplements packed with the essential vitamins, minerals, and other nutrients that keep your immune system operating at peak capacity.

So whether you’re noticing signs of a weakened immune system or want to keep your natural immunity strong, be sure to take your vitamins with Cymbiotika!


  1. NCBI. Role of Vitamin A in the Immune System. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162863/
  2. National Institutes of Health. Vitamin A: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/
  3. NCBI. B Vitamins and Their Role in Immune Regulation and Cancer. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693142/
  4. NCBI. Vitamin C and Immune Function. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5707683/
  5. U.S. Department of Agriculture. FoodData Central Search Results: Elderberries, raw. https://fdc.nal.usda.gov/fdc-app.html#/food-details/171727/nutrients
  6. National Institutes of Health. Vitamin C: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/
  7. NCBI. Vitamin D and the Immune System. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
  8. NCBI. Vitamin effects on the immune system: vitamins A and D take centre stage. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906676/
  9. NCBI. Regulatory role of vitamin E in the immune system and inflammation. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7011499/
  10. National Institutes of Health. Vitamin E: Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/

by / Mar 07, 2022