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How do Vitamins C, D, & Zinc Help the Immune System?

Key Takeaways:

  • Vitamin C, D, and zinc help support a healthy immune system on a cellular level.
  • While you can find vitamin C, D, and zinc in certain foods, taking a quality supplement is the easiest way to ensure you’re getting enough of each vitamin and mineral.

Vitamin C, vitamin D, and zinc are three of the best supplements to support a healthy immune system. But how do these powerful nutrients keep you feeling your best?

We dive into the science behind these immune-supporting nutrients and help you choose the right supplements for your needs.


How does vitamin C help the immune system?

Vitamin C is an essential micronutrient for humans. However, the body cannot make it on its own, which means it must be consumed either through food or supplements. Vitamin C is water-soluble, and because our bodies don’t store water-soluble vitamins well, vitamin C needs to be replenished every day.1

Vitamin C supports the body’s immune defense through various cellular functions of both the innate and adaptive immune systems. Innate immunity is the body’s first line of defense against pathogens. It is general and non-specific, which means it does not differentiate between types of pathogens. Adaptive immunity is a type of immunity that is built up as we are exposed to illnesses or get vaccinated.

Vitamin C is also a potent antioxidant and helps fight free radicals that can cause oxidative stress. It supports the functioning of white blood cells, which are important components of a healthy immune system.2


Which foods contain vitamin C?

Many foods, especially fruits and vegetables, are rich in vitamin C. Citrus fruits such as oranges and grapefruits, as well as less common fruits like pineapple, kiwi, and watermelon, are all great sources of vitamin C. Many vegetables are also rich sources of vitamin C, including broccoli, spinach, green and red bell peppers, sweet potatoes, and tomatoes.

Chart Information

*Chart information from https://ods.od.nih.gov/pubs/usdandb/VitaminC-Content.pdf


Best vitamin C supplements for your immune system

Not all vitamin C supplements are created equal, and it’s important to choose one that has great absorption, stays in the body for a long time, and is produced with quality ingredients and standards, such as Solgar®’s Ester-C®.


Solgar® Ester-C Plus 1000mg


This elevated vitamin C supplement is clinically-shown to last longer inside your white blood cells – up to 24 hours!* It is also non-acidic and gentle on sensitive stomachs. Just one capsule taken daily helps support immune and upper respiratory health, and harnesses the power of antioxidants to help fight against free radicals.*

Best vitamin C supplement for kids


These tasty tapioca-based vitamin C gummies support immune health and are made with naturally sourced colors and flavors. They are also non-GMO, vegan, gluten-free, and dairy-free!


How does vitamin D help the immune system?

Vitamin D is a fat-soluble vitamin that helps the body absorb and retain other nutrients, like calcium and phosphorus. It also helps support healthy bones, teeth, and a healthy immune system.*

Vitamin D has been shown to support the immune system in various ways. The active form of vitamin D tempers the damaging inflammatory response of some white blood cells while boosting immune cell’s production of microbe-fighting proteins.3

A study found that adults who have low vitamin D levels are more likely to report having had a recent cough, cold, or upper respiratory tract infection.4


Which foods contain vitamin D?

Few foods are naturally rich in vitamin D. The best sources of vitamin D are fatty fish such as salmon, tuna, and swordfish. Small amounts of vitamin D are found in egg yolks, cheese, and beef liver.5

Another way your body makes vitamin D is when sunlight converts a chemical in your skin into an active form of the vitamin (calciferol).

It can be difficult to get enough vitamin D from food and even sunlight if you wear SPF daily or live in a place with less sunlight. Taking a quality vitamin D supplement with excellent absorption is the best way to make sure you’re getting your daily dose of vitamin D.


Best vitamin D supplements for your immune system


One softgel taken daily helps maintain a healthy immune system, strong bones and teeth, and optimal nerve and muscle function.* Our convenient, oil-based softgels are easy to swallow and absorb.


Solgar® Vegan Vitamin D3


Because most food sources of vitamin D are animal products, vegans and vegetarians may be at a greater risk of not getting enough vitamin D. Solgar® Vegan Vitamin D3 is made with naturally and responsibly sourced lichen, a plant that grows on rocks and trees and naturally produces vitamin D3.

This softgel form offers better absorption and is plant-based, made with lichen, sunflower seed oil, tapioca starch, vegetable glycerin, and maltitol.

Best vitamin D supplement for kids


These tapioca-based gummies support bone health and are made with naturally sourced colors and flavors. And they’re non-GMO, gluten-free, and dairy-free!


How does zinc help the immune system?

Zinc is a trace mineral, meaning that your body only needs it in small amounts. Nevertheless, zinc is still essential for almost 100 enzymes to carry out vital chemical reactions. It helps in the creation of DNA, the growth of cells, building proteins, healing damaged tissue, and of course, supporting a healthy immune system.6

Zinc supports the growth and normal functioning of cells, so even a mild or moderate deficiency can slow down the activity of immune cells such as lymphocytes, neutrophils, and macrophages that protect the body from viruses and bacteria.7

Zinc also helps regulate immune function, exhibits antioxidant activity, and helps maintain a balanced inflammatory response in your immune system.8


Which foods contain zinc?

Meats, poultry, and seafood are rich in zinc. According to Harvard Health, some plant foods like legumes and whole grains are also good sources of zinc, but they also contain phytates that can bind to the mineral and lower its absorption.9

The easiest way to get immune-supporting zinc that absorbs easily into the body is by taking a zinc supplement.


Best zinc supplements for your immune system

When choosing a zinc supplement for immune support, it’s essential to look for one that is made by a quality, trustworthy brand and absorbs effectively into the body. Solgar® offers a range of zinc supplements in various forms that effectively deliver zinc to the body.*


Solgar® Zinc Picolinate provides zinc in a highly-absorbable, chelated form. It helps support immune system health, healthy skin and eyes, and more.* And it’s non-GMO, vegan, gluten-free, dairy-free, and kosher!


Solgar® Earth Source® Koji Fermented Zinc


This unique supplement is a food-fermented, vegan-friendly zinc that supports immune health and healthy skin and eyes.* Earth Source® Koji Fermented Zinc is a bioavailable form of zinc, which means the body easily absorbs it.

Best zinc supplement for kids


Solgar® Kangavites® offer a range of vitamins and minerals for your child, including zinc. And they’re vegan, gluten-free, and dairy-free!


Immune support supplement with vitamin C, D, and zinc


Solgar® Ester-C Plus Immune Complex


If you’re looking for a supplement that contains vitamin C, D, and zinc, look no further than Solgar® Ester-C® Plus Immune Complex.

This unique supplement gives you the ultimate combination of immune-supporting ingredients, including Ester-C®, vitamin D, and zinc, as well as immune-supporting herbal ingredients elderberry, astragalus, and echinacea.* It even includes magnesium and a range of B vitamins.
Its unique softgel form ensures quick absorption, and it’s non-GMO, gluten-free, and dairy-free.


Summing it up

Vitamin C, vitamin D, and zinc are all essential for immune system health. Each of these vitamins and minerals can be found in food, but the easiest way to get your daily dose is by taking a quality supplement, such as those offered by Solgar®.

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*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.

The information provided on this site is intended for your general knowledge only and is not a substitute for professional medical advice or treatment for specific medical conditions. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition. The information on this website is not intended to diagnose, treat, cure or prevent any disease. Never disregard medical advice or delay in seeking it because of something you have read on the Solgar® site.