Vitamin C is a cofactor for collagen synthesis, carnitine production, and antioxidant defense, and it significantly improves absorption of non-heme iron from plant foods. Deficiency causes scurvy — gums bleeding, wounds failing to heal — which historically struck sailors on months-long voyages without fresh produce.
How much is enough
The recommended intake is 75–90 mg per day for adults, with an upper limit of 2,000 mg. Smokers need about 35 mg more, since oxidative stress consumes it faster. Requirements are easily met: a single serving of most raw vegetables or citrus covers the baseline.
What the ranking really shows
Our vitamin C ranking is topped by raw peppers, raw parsley, citrus, and kiwi. Values above 100 mg per 100 g are common at the top of that list. Notice the word raw: vitamin C is water-soluble and heat-sensitive, so boiling and prolonged cooking destroy a large share of it.
Food vs supplements
At food-level doses, vitamin C from whole produce behaves like any other nutrient in a matrix of fiber and water. Mega-doses beyond the upper limit offer no proven additional benefit for most people and can cause digestive upset. The practical goal is consistently eating colorful produce rather than chasing a number.
Pairing trick
Because vitamin C boosts non-heme iron absorption, combining legumes, greens, or fortified grains with something rich in vitamin C — bell peppers, citrus, tomatoes — measurably increases how much iron your body takes from the plant side of the plate.