Vitamin C

Alright, so we all know everybody is talking about Vitamin C (L-ascorbic acid) but why is it so important and associated with having immune boosting properties? Vitamin C is present naturally in a lot of foods you probably have in your fridge right now, or are planning to get the next time you go grocery shopping. It is also added to a lot of foods in the market and available as a dietary supplement. When it comes to immune boosting properties, it is considered an important physiological antioxidant, which means, it limits the effects of free radicals and might help prevent or delay certain diseases involved with oxidative stress.

With the current COVID-19 situation, accessibility to vitamin C supplements may be limited in certain areas, and this is why it is important to get familiar with vitamin C-rich foods, so we can add these to our diets. At first, I was surprised when I saw some of the selected foods on the following list. For example, I used to know oranges and citrus foods are considered vitamin C-rich foods, but never thought potatoes had a significant amount of this vitamin. The following table shows an  attached list of foods and the recommended amounts for each fruit or veggie. It is very important to remember that the vitamin C content in food may be reduced by heat and prolonged storage. Luckily, most of these foods can be safely eaten raw.

Table 1. Selected Food Sources of Vitamin C (reference: U.S. Department of Agriculture, Agricultural Research Service)

When is it too much? Vitamin C has low toxicity and is not believed to cause serious side effects.  Common complaints after high intakes include gastrointestinal disturbances, such as diarrhea, nausea, cramping and it is all attributed to the unabsorbed vitamin C in the body. As you all have heard, everything is good in moderation, and this is why consuming five varied servings per day can provide more than 200 mg of vitamin C. In case you are wondering, in healthy individuals, the Recommended Dietary Allowance of Vitamin C for male adults is 90 mg per day and 75 mg per day for female adults.

Before starting any supplements of vitamin C, talk to your primary care provider about the use of these while taking medications such as chemotherapy, radiation and statins and to your local pharmacist with any questions about any potential medication interactions or dosing.


References

Jacob RA, Sotoudeh G. Vitamin C function and status in chronic disease. Nutr Clin Care. 2002;5(2):66‐74. doi:10.1046/j.1523-5408.2002.00005.x

U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, 2019.

National Institutes of Health. Vitamin C. https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/#en4 (Accessed 2020 May 21)

Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoidsexternal link disclaimer. Washington, DC: National Academy Press, 2000.