Vitamins C and D: What You Need To Know

When you think of nutrients that support the immune system, vitamins C and D likely come to mind. You may have heard that these two vitamins play a role in the body’s immune defense, but are you familiar with how exactly they work? 

In this post, you’ll learn about the functions of vitamins C and D, how much of each vitamin you need, food sources, and how to know if you get enough of them.

Vitamins C and D and Immunity

Vitamin C is a water-soluble nutrient that’s found in a variety of foods and acts as an antioxidant in the body. As such, it can protect immune cells from damage and may also stimulate their production and function (1).

In addition, vitamin C improves the absorption of non-heme iron from plant foods. Since iron is required for proper immune function, the role of vitamin C in enhancing iron absorption is another way it supports immunity (2).

It’s widely believed that vitamin C supplements boost immune function. However, research on the topic is mixed, with some studies suggesting that supplements may reduce the duration and severity, but not the incidence, of the common cold (3). 

While the jury’s still out on the benefits of supplements, it’s still hugely important to get enough vitamin C from food sources (like So Good So You Shots) to support the regular functioning of the immune system. 

Vitamin D, on the other hand, is a fat-soluble nutrient that’s only found in a few food sources. The best source of vitamin D is the sun, since UV rays trigger vitamin D synthesis in the body when they hit your skin (4). 

Most immune cells have receptors for vitamin D, which suggests that this nutrient helps regulate immune response (5).Vitamin D deficiency is also linked to an increased susceptibility to infection (6). Maintaining adequate vitamin D status is therefore important for optimal immunity.

Recommended Intakes and Food Sources

Adult men and women (under 70 years of age) need 15 mcg (600 IU) of vitamin D per day. For vitamin C, men should aim for 90 mg while women should get 75 mg per day. 

Some food sources of vitamin D are sockeye salmon (3 ounces provides 14.2 mcg), vitamin D fortified milk, and eggs. Mushrooms that are exposed to UV light are one of the only vegan sources of vitamin D (4). 

Vitamin D is also available in two supplemental forms: vitamin D2 and D3. Most vegan-friendly supplements contain vitamin D2. Compared to supplemental forms of vitamin D3, vitamin D2 is not as effective at raising blood levels (7). Fortunately, the immunity shot powered by camu camu has a vegan-friendly version of vitamin D3!

Vitamin C can be found in a much wider variety of foods than vitamin D. Just ½ cup of raw red pepper contains more than the recommended daily intake for vitamin C (95 mg), while a medium orange provides close to 80% of your daily needs (3). Kiwi, broccoli, Brussels sprouts, and strawberries are other sources of vitamin C.

Are you getting enough? (or too much?)

Most people who eat a balanced diet get plenty of vitamin C. True vitamin C deficiency, known as scurvy, is very rare in the United States. 

If you eat lots of fruits and vegetables, you may be more likely to get too much vitamin C than not enough. But overconsumption of vitamin C, especially from foods and not supplements, is generally not a concern. Vitamin C has low toxicity and can be excreted in the urine when you consume more than your body needs (3).

Meeting vitamin D needs is more difficult. Most experts suggest exposing your skin to 10 to 30 minutes of midday sunlight at least a few days a week to get enough vitamin D. People with darker skin may need more sun exposure, but those who have fair skin or increased susceptibility to skin cancer should limit their time in the sun. Plus, if you live in a northern location, such as north of Indianapolis or Denver, sunlight from November through March is insufficient for the body to produce enough vitamin D (5).

Food and supplements can help make up for shortcomings in vitamin D synthesis from sun exposure. However, some people may still be at risk of vitamin D insufficiency or deficiency, marked by extreme fatigue, getting sick more often, and poor mood. If you have limited sun exposure, dark skin, or live in a northern location, and you struggle with getting enough vitamin D from food, consider speaking to your healthcare provider about a supplement. 

Adding the new camu camu immunity shot to your routine is also a great way to meet your daily needs for both vitamins C and D. Each shot has 140% of the Daily Value (DV) for vitamin C and 100% of the DV for vitamin D3, in a vegan-friendly form. 

So Good So You and its blog materials are not intended to treat, diagnose, cure or prevent any disease. All material on the So Good So You blog is provided for educational purposes only. Always seek the advice of your physician or another qualified healthcare provider for any questions you have regarding a medical condition, and before undertaking any diet, exercise or other health-related programs.


Lizzie Streit, MS, RDN, LD. Registered Dietitian and self-proclaimed veggies enthusiast, Lizzie partners with So Good So You and serves and a culinary nutrition expert. Keep an eye out for plant-based recipes, ingredient breakdowns, and much more from Lizzie.


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