What Is the Recommended Daily Allowance (RDA) of Vitamin C?
It’s extremely difficult to overdose on vitamin C through food alone, but it is possible to experience side effects if you somehow overdo it on supplements. The NIH recommends that adults get no more than 2,000 milligrams (mg) a day. It’s equally difficult to be vitamin C deficient, unless you live somewhere with little access to fruits and vegetables. Moore says at the very minimum your body needs 10 mg of vitamin C per day, but the recommended daily allowance (RDA) varies depending on age, gender, life stage, and lifestyle choices like smoking.
According to research published by the U.S. Food and Nutrition Board, among people age 19 and older, the RDA is 90 mg for men and 75 mg for women. Anyone who smokes regularly needs extra vitamin C, and should get an additional 35 mg per day. Pregnant women need 85 mg, and lactating women require 120 mg of vitamin C.
The Office of Dietary Supplements lists certain groups of people who have a higher risk of vitamin C deficiency. Research, such as a study published in July 2020 in the journal Nutrients, has shown smokers have lower vitamin C levels than nonsmokers, and thus they need a little extra in their diet. Infants who are fed evaporated or boiled milk, both of which are deficient in vitamin C, may not be getting enough of the nutrients they need. Medical conditions that cause malabsorption and certain chronic diseases may reduce the body’s ability to absorb vitamin C, increasing the amount the body needs, according to the International Foundation for Gastrointestinal Disorders.
Michael Wald, MD, ND, PhD, a registered dietitian in Chappaqua, New York, and the host of the podcast Ask the Blood Detective, says the RDA is the minimum amount needed to prevent vitamin C deficiency, and it isn’t necessarily representative of the ideal vitamin C value each person needs.
What Foods Are the Highest in Vitamin C?
Because, per theNIH, the FDA does not require food labels to list the vitamin C that naturally occurs in foods, only the amount of vitamin C that has been added, it can be difficult to know which packaged foods are good sources. Luckily, plenty of whole foods such as fruits and vegetables are chock-full of C. Some, like red bell peppers, can provide more than 100 percent of the DV of the vitamin in one or two servings, as USDA data demonstrates.
“People should always begin with a diet high in fruits and vegetables,” says Dr. Wald. “Age, genetics, absorption, disease, exercise, stress, sleep, alcohol, and various other lifestyle factors all play a role in the amount of vitamin C one needs.”
Note that cooking affects the nutrient content of foods. Because vitamin C is heat sensitive and water soluble, the longer you cook a food with vitamin C, the more C it loses, notes an article published in April 2018 in the journal Food Science and Biotechnology. The authors wrote that microwaving a food with vitamin C led to better retention of the nutrient than boiling. It's even better if you can eat high–vitamin C foods raw.
Vegetables That Are High in Vitamin C
Here are some of the foods recommended by the NIH that contain vitamin C, as well as flavonoids and bioflavonoids (powerful antioxidants found in fruits and veggies) that work with vitamin C. The following vegetables are excellent sources of vitamin C, according to USDA data.
- Bell peppers A 1 cup portion of chopped red bell peppers has 191 mg of vitamin C.
- Red and green chili peppers One red chili pepper contains 64.8 mg of vitamin C.
- Dark green leafy vegetables This includes garden cress, kale, mustard greens, Brussels sprouts, cauliflower, and broccoli. For example, 1 cup of chopped broccoli has 81.2 mg of vitamin C.
- Potatoes One medium-size potato contains 17.7 mg of vitamin C.
Fruits That Are High in Vitamin C
Citrus fruits and fruit juices are famous for being high in vitamin C, but they aren’t alone — or even the best source. The following fruits are considered excellent sources of vitamin C, according to USDA data.
- Guava Just one of these tropical pink-fleshed fruits delivers 125 mg of vitamin C.
- Strawberries Berries are brimming with antioxidants, and 1 cup of sliced strawberries has 97.6 mg of vitamin C.
- Papaya Another tropical pick, 1 cup of this orange-hued fruit’s cubed flesh yields 88.3 mg of C.
- Oranges Practically synonymous with vitamin C, one whole navel orange offers a hefty 82.7 mg of vitamin C.
- Kiwi Small but powerful, one kiwifruit has 64 mg of vitamin C.
- Blackberries 1 cup of blackberries has 30 mg of vitamin C.
- Lemons and limes A lemon contains 34.4 mg of C, while a smaller lime has 19.5 mg of vitamin C. It’s unlikely you’ll eat either of these fruits whole, but the juice delivers most of that amount.
