Most adults need 75 to 90 mg of vitamin C a day: 75 mg for women and 90 mg for men, according to the NIH Office of Dietary Supplements, with 35 mg more if you smoke. The best food sources aren’t just oranges: per 100 g, guava, red peppers, kiwi, kale, broccoli and Brussels sprouts all have more, based on USDA FoodData Central. Eating a variety of fruit and vegetables each day easily covers it. Vitamin C is sensitive to heat and water, so raw or lightly cooked foods keep more.
What vitamin C does
Vitamin C helps your body make collagen, which keeps skin, blood vessels, bones and cartilage healthy. It acts as an antioxidant, supports the immune system, and helps your body absorb iron from plant foods. Your body can’t make or store much of it, so you need a regular supply from food, as the NIH Office of Dietary Supplements explains.
How much vitamin C you need
| Group | Recommended daily amount (US) |
|---|---|
| Men 19 and over | 90 mg |
| Women 19 and over | 75 mg |
| Pregnancy | 85 mg |
| Breastfeeding | 120 mg |
| Smokers | Add 35 mg |
| Upper limit for adults | 2,000 mg |
Source: the NIH Office of Dietary Supplements. Other countries use slightly different figures, but all are easy to reach from food.
The best food sources of vitamin C
Per 100 g, raw, from USDA FoodData Central:
| Food (100 g) | Vitamin C |
|---|---|
| Guava | 228 mg |
| Red bell pepper | 128 mg |
| Kale | 93 mg |
| Kiwi (green) | 93 mg |
| Broccoli | 89 mg |
| Brussels sprouts | 85 mg |
| Strawberries | 59 mg |
| Orange | 53 mg |
| Lemon (without peel) | 53 mg |
| Cauliflower | 48 mg |
| Potato (with skin) | 20 mg |
| Tomato | 14 mg |
Half a red pepper (about 75 g) or one kiwi (about 75 g) provides most of a woman’s daily need on its own.
How cooking affects vitamin C
Vitamin C breaks down with heat and dissolves into cooking water. Kale shows how much difference it makes: per 100 g, raw kale has about 93 mg of vitamin C, while boiled kale has about 18 mg, according to USDA values. To keep more:
- Eat some fruit and vegetables raw.
- Steam, microwave or stir-fry briefly instead of boiling.
- Use as little water as possible, or eat the cooking liquid in soups and sauces.
- Cut vegetables just before cooking or eating.
Our guide to how to cook kale shows the raw vs cooked difference in more detail.
Vitamin C and iron
Vitamin C helps your body absorb iron from plant foods. The NHS recommends eating vitamin C-rich foods at the same meal as plant sources of iron, such as beans, lentils and fortified cereals. A squeeze of lemon on lentils, or peppers in a bean chili, both help. Our guide to iron-rich foods explains more.
Do vitamin C supplements prevent colds?
For most people, no. The NIH Office of Dietary Supplements summarizes research showing that regular vitamin C supplements don’t reduce how often most people catch colds, though they may slightly shorten them. People under heavy physical stress, such as marathon runners, may be an exception. Most people get enough vitamin C from food without supplements.
Can you have too much?
It’s very hard to get too much from food. High-dose supplements above the 2,000 mg upper limit can cause diarrhea, nausea and stomach cramps, according to the ODS. People with certain conditions, such as kidney stones or haemochromatosis (iron overload), should talk to their doctor before taking vitamin C supplements.
Vitamin C deficiency
Severe deficiency causes scurvy, which the ODS describes as rare but still seen in people with very limited diets. Symptoms include tiredness, swollen and bleeding gums, easy bruising and slow wound healing. People at higher risk include those who eat very few fruits and vegetables, smokers, and people with some medical conditions. If you’re worried, see your doctor.
Easy ways to get more vitamin C
- Add sliced red pepper to salads, wraps and stir-fries.
- Eat a kiwi or an orange as a snack.
- Add berries to breakfast. Our guide to strawberries and other berries compares them.
- Serve broccoli or Brussels sprouts lightly steamed or roasted.
- Squeeze lemon over fish, vegetables and salads.
- Keep frozen berries and broccoli in the freezer for days when fresh ones run out.
Vitamin C on special diets
- Keto and low-carb diets: many fruits are limited, so rely on low-carb sources such as red peppers, broccoli, cauliflower, kale and small portions of berries. In the Keto-Med trial, people ate less vitamin C on keto than on a Mediterranean-style diet.
- Vegan diets: fruit and vegetables provide plenty, and vitamin C also helps with iron absorption from plant foods.
- Older adults and people with small appetites: a glass of orange juice with a meal (up to 150 ml, as the NHS suggests) can help, along with fruit and vegetables.
Common questions
Is orange juice a good source of vitamin C?
Yes. Per 100 g, orange juice has about 50 mg, almost as much as a whole orange, according to USDA values. But juice has little fiber and counts as free sugar, so the NHS suggests keeping it to one small glass a day.
Does vitamin C help the immune system?
Vitamin C is needed for normal immune function, which is why deficiency affects health. Taking more than you need doesn’t boost your defenses further for most people.
Can I get enough vitamin C without fruit?
Yes. Vegetables such as red peppers, broccoli, Brussels sprouts, kale and cauliflower are excellent sources, as the table above shows. Eating some of them raw or lightly cooked helps.
Does vitamin C break down in stored food?
Vitamin C is sensitive to heat, light and air, so fresh produce gradually loses some of it during storage. Buying fresh produce often, storing it in the fridge, and using frozen vegetables and fruit helps keep more of it.
This article is general information, not medical advice. Talk to your doctor or a registered dietitian before making big changes to how you eat, especially if you have a health condition, take regular medication, or are pregnant or breastfeeding.
