11 Foods Rich in Vitamin C (Ascorbic Acid) for Immune Support

Ascorbic acid, the scientific name for vitamin C, supports immune function. Eating ascorbic acid-rich foods helps your immune system work properly.

1. Guava

Vitamin C: 228 milligrams (mg) per 100 grams (g)

This tropical fruit is a supreme source of ascorbic acid, offering several times the amount found in an orange to significantly boost immune function. It also contains lycopene, an antioxidant that protects cells.

2. Brussels Sprouts

Vitamin C: 143 mg per 100 g (raw)

These mini cabbages deliver ascorbic acid to support immune cell function, while their vitamin K helps maintain normal blood clotting and bone health.

3. Red Bell Pepper

Vitamin C: 142 mg per 100 g

These vibrant vegetables deliver ascorbic acid amounts that surpass many citrus fruits, providing solid support for skin and mucous membranes, the body’s first immune barrier.

Beta-carotene in red bell peppers helps maintain healthy vision. Their ruby color signals a later stage of ripening, resulting in a naturally sweeter taste and higher nutrient density.

4. Yellow Bell Pepper

Vitamin C: 139 mg per 100 g

These vegetables are an exceptionally potent source of ascorbic acid, offering high antioxidant power to help support and protect immune cells from everyday stress.

They also provide carotenoids that contribute to eye health. Yellow peppers are fully ripened green peppers; their higher vitamin C levels develop alongside their sweeter flavor.

5. Kale

Vitamin C: 93 mg per 100 g (raw)

Kale, a leafy green, provides a valuable dose of ascorbic acid for immune health. It’s also packed with lutein and zeaxanthin, two carotenoids that lower the risk of age-related macular degeneration.

6. Broccoli

Vitamin C: 91 mg per 100 g (raw)

This cruciferous vegetable has a generous dose of ascorbic acid paired with sulforaphane, which helps reduce the secretion of an inflammatory cytokine (protein) called IL-6. This may help reduce the risk of certain types of cancers. 

7. Papaya

Vitamin C: 61 mg per 100 g

This tropical fruit, known as “fruit of the angels,” combines ascorbic acid with carotenoids, delivering a one-two punch for resilient immune defense and tissue repair. The natural enzyme papain also helps break down proteins and may promote better digestion.

8. Kiwi

Vitamin C: 59 mg per 100 g

This small fuzzy fruit is packed with ascorbic acid to help keep immune defenses resilient. It also has vitamin E for extra cell protection.

9. Strawberries

Vitamin C: 59 mg per 100 g

These popular berries provide ascorbic acid for immune support. Despite their sweetness, strawberries are mostly water and naturally low in calories.

10. Oranges

Vitamin C: 59 mg per 100 g

Eating this vitamin C icon regularly may help reduce the duration and severity of cold symptoms. Oranges also have folate (vitamin B9), which supports red blood cell formation.

Beyond their high ascorbic acid content, oranges have bioactive compounds, like citrus bioflavonoids, that may boost vitamin C’s overall ability to support immune health.

11. Pineapple

Vitamin C: 48 mg per 100 g

While pineapple’s ascorbic acid supports the body’s immune defenses, its uniquely high levels of the enzyme bromelain act as a powerful anti-inflammatory agent.

Other Foods With Ultra-High Ascorbic Acid

These fruits contain far more ascorbic acid than common produce, but they’re almost impossible to find in most U.S. grocery stores:

• Kakadu plum: An Australian superfruit with up to 3,150 mg of vitamin C per 100 g.
• Camu camu: A tart Amazonian berry that supplies up to 2,280 mg per 100 g.
• Acerola cherry: These Barbados cherries deliver 1500–4500 mg per 100 g.
• Sea buckthorn: This Eurasian berry with a citrusy taste has about 900 mg per 100 g.
• Amla (Indian gooseberry): This sour fruit contains 193–720 mg per 100 g.