Vitamin C is an important vitamin that acts as a powerful antioxidant. It helps to fight off free radical damage and promote optimal immune function. Also, it is used for tissue and hormone synthesis, wound healing, and improves absorption of certain minerals from the diet including iron, copper, and chromium. Vitamin C supports the cardiovascular, neurological, endocrine, and immune systems.
Vitamin C deficiency, while rare in the United State, causes scurvy. Symptoms of scurvy include: fatigue, gum inflammation/bleeding gums, depression, anemia, small red or purple bumps on the skin, joint pain, poor wound healing, and corkscrew hairs. Populations at risk for vitamin C deficiency include smokers and those exposed to second-hand smoke, infants fed evaporated or boiled milk, those with malabsorption and chronic diseases, and those with limited access to fruits and vegetables.
Sources of Vitamin C include:
|Food||Vitamin C (mg)||Percent (%)
|Red Pepper, sweet, raw, ½ cup||95||158|
|Orange Juice, ¾ cup||93||155|
|Orange, 1 medium||70||117|
|Grapefruit Juice, ¾ cup||70||117|
|Kiwifruit, 1 medium||64||107|
|Green Pepper, sweet, raw, ½ cup||60||100|
|Broccoli, cooked, ½ cup||51||85|
|Strawberries, fresh, sliced, ½ cup||49||82|
|Brussels Sprouts, cooked, ½ cup||48||80|
|Grapefruit, ½ medium||39||65|
|Broccoli, raw, ½ cup||39||65|
|Tomato Juice, ¾ cup||33||55|
|Cantaloupe, ½ cup||29||48|
|Cabbage, cooked, ½ cup||28||47|
|Cauliflower, raw, ½ cup||26||43|
|Potato, baked, 1 medium||17||28|
|Tomato, raw, medium||17||28|
|Spinach, cooked, ½ cup||9||15|
|Green Peas, frozen, cooked, ½ cup||8||13|
What Should I Know About Vitamin C?
Heat, exposure to oxygen, and acidity can all easily destroy Vitamin C. Therefore, eat a combination of cooked and raw food sources of vitamin C.
The Recommended Dietary Allowance (RDA) for vitamin C is based on age, gender, lifecycle phase, and smoking habits. For adults ages 19 and older, the RDA for men is 90 mg and for women is 75 mg. Especially relevant is that the need for smokers is much higher than non-smokers because smokers have greater oxidative stress from toxins in cigarette smoke. Therefore, they generally have lower levels of vitamin C in their blood. Consequently, those exposed to second-hand smoke are also at risk for vitamin C deficiency. For smokers ages 19 and older, the RDA for men is 125 mg and women is 110 mg. The tolerable upper intake level (TUL) for vitamin C is 2,000 mg. Taking too much supplemental vitamin C may lead to diarrhea, nausea, and stomach cramps. Either discontinue use if these symptoms occur, or reduce your dose.
Are There Different Types of Supplemental Vitamin C?
Your vitamin C status is assessed based on a nutrition focused physical exam, your intake questionnaire, and questions during your consultation. As a result, long or short term supplementation may be advised. There are many forms of vitamin C available including ascorbic acid (the most common), sodium ascorbate, calcium ascorbate, other mineral ascorbates, and ascorbic acid with bioflavonoids. Currently there is no evidence that any form is better than another. Many Vitamin C supplements come from corn. Therefore, if you are allergic or have a sensitivity, check your supplement to make sure it is corn free.
In conclusion, not everyone should be supplementing with Vitamin C. Those who are undergoing cancer treatment, including either chemotherapy or radiation, should not supplement with vitamin C without first discussing with their doctor and oncologist.
For more information about vitamin C, visit: https://ods.od.nih.gov/factsheets/VitaminC-Consumer/
McGuire, M. & Beerman, K. A. (2013). Nutritional Sciences: From Fundamentals to Food. 3rd ed. Belmont, CA: Wadsworth.