What Is Vitamin C (Ascorbic Acid)?

Vitamin C is considered to be an essential vitamin. This means the human body cannot produce it, so it needs to be obtained through vitamin C-rich foods to get adequate amounts. ^[5] Mayo Clinic Staff. Vitamin C. (2025, Aug. 14). Mayo Clinic. , ^[6] National Institute of Health (NIH). Vitamin C fact sheet for health professionals. (n.d.) NIH

Vitamin C plays an important role in immune defense and tissue repair. In terms of immune defense, foods rich in vitamin C provide antioxidant protection, support white blood cells, enhance the skin barrier, and help regulate inflammation. Additionally, vitamin C plays a vital role in collagen synthesis, wound healing, and the prevention of tissue damage. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Top Foods With Vitamin C

Vitamin C is abundant in fresh fruits and vegetables. Here are the top sources of this important nutrient:

Fruits Rich in Vitamin C

Fruits that are rich in vitamin C are generally brightly colored, fresh, and slightly tart. Ascorbic acid is the form of vitamin C found in these fruits. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.

Here are some delicious fruits that are excellent sources of vitamin C:

• Citrus fruits like oranges, lemons, and grapefruits are full of vitamin C, which helps keep your body’s tissues healthy and protects your cells from damage.
• Both kiwis and guavas are packed with vitamin C, helping protect your body from damage caused by sunlight. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.
• Mangoes and papayas are tropical fruits full of vitamin C that protect you against UV damage and cellular damage. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.
• Strawberries are low in sugar and are a great source of vitamin C, making them an excellent snack when you’re craving something sweet. Their vitamin C helps protect other beneficial compounds in the fruit, which may support heart and brain health when eaten regularly. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.
• Pineapples are another popular fruit that contains a compound called bromelain. Both bromelain and vitamin C support human tissue cells and provide defense and tissue repair. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.
• Acerola cherries are native to tropical regions and are full of vitamin C. This fruit can help support skin health and reduce the effects of sun exposure, including sunburn, early aging, and uneven skin pigmentation. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.
• Cantelopes are another good source of this essential vitamin, which works with beta-carotene to protect your body from cell damage. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.

Vegetables Rich in Vitamin C

While fruits like oranges likely come to mind when you think of Vitamin C, veggies are also a great source of this powerful nutrient. Below are the vegetables highest in Vitamin C and how they benefit the human body:

• Red bell peppers are an excellent source of vitamin C. As they ripen, they gain more nutrients that help boost your immune system, keep your skin and bones healthy, and protect your cells from damage. This vegetable also enhances iron absorption, helping prevent anemia and reducing inflammation.
• Broccoli uses vitamin C to protect its chlorophyll. ^[2] Kaleem, M. (n.d.). Nutrition and eye health. Johns Hopkins Medicine. When humans consume broccoli, that same vitamin C helps keep our cells strong and fight off harmful free radicals. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.
• Kale and other leafy greens, such as spinach, lead to increased production of antioxidants in the body, including vitamin C. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.
• Tomatoes are a vitamin C-rich food, which helps protect their cells, and yours. Eating tomatoes can support your immune system, keep your skin healthy, and help prevent cell damage.
• Potatoes also contain vitamin C. Since most people eat potatoes often, they can be a simple way to add vitamin C to your diet and support your overall health. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.
• Chili peppers can cause a stinging or burning feeling on your skin, tongue, or lips. However, despite their uncomfortable stinging, they can actually help relieve pain over time, boost your metabolism, and provide antioxidant benefits. ^[7] Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline.

How to Get Enough Vitamin C Daily

Mixing fruits, vegetables, and fresh juices daily can help you get your fair share of vitamin C. ^[8] Zelman K. (2024, January 9). The benefits of Vitamin C. WebMD.

The following are some tips to get enough daily Vitamin C: ^[8] Zelman K. (2024, January 9). The benefits of Vitamin C. WebMD.

• Eat raw foods whenever possible, as vitamin C is heat-sensitive.
• Avoid overcooking and prolonged storage.
• Pair vitamin C-rich foods with iron-rich meals to enhance absorption.
• Enjoy smoothies and salads to incorporate vitamin C sources into a daily diet.

Key Functions and Health Benefits of Vitamin C

Vitamin C is an antioxidant and water-soluble. It plays a critical role in collagen synthesis, improves iron absorption, and supports eye health.

Boosts Immune System

Vitamin C-rich foods stimulate white blood cells and antibodies. They support white blood cells (WBCs) by enhancing the function of phagocytes (e.g., neutrophils), which surround and engulf harmful microbes. Vitamin C also promotes the proliferation and function of T cells and B cells, which are crucial components of adaptive immunity. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Vitamin C sources can help shorten the duration of colds. They help modulate the production of cytokines, which are signaling molecules involved in immune responses, thereby helping prevent excessive inflammation. Vitamin C benefits include its role as a powerful antioxidant, which helps protect immune cells from damage by reactive oxygen species (ROS), a group of highly reactive molecules derived from oxygen and generated during immune responses. Vitamin C's antioxidant role protects immune cells from ROS damage, allowing the cells to function effectively. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Promotes Collagen Formation

Finally, foods high in vitamin C strengthen and enhance the skin barrier. Vitamin C for skin promotes collagen synthesis. This helps maintain healthy skin and mucous membranes, the human body's first line of defense against pathogens. Vitamin C supports skin elasticity, wound healing, and connective tissues. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Powerful Antioxidant

Vitamin C-rich foods protect cells from aging and oxidative stress, the accumulated damage from ROS. Vitamin C can neutralize ROS, preventing them from damaging key substances such as lipids, DNA, and proteins. Furthermore, the human brain is highly susceptible to oxidative stress. This is a key factor in cognitive decline and neurodegenerative diseases. Vitamin C benefits include protecting neurons and supporting the synthesis of neurotransmitters such as dopamine and norepinephrine. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211. , ^[6] National Institute of Health (NIH). Vitamin C fact sheet for health professionals. (n.d.) NIH

Vitamin C also works synergistically with vitamin E by helping it regenerate. Vitamin E is a fat-soluble antioxidant, and its active component is tocopherol. It can protect the human body's cell membranes by preventing lipid peroxidation, which damages membrane lipids. Vitamin E becomes oxidized during this process, thereby forming a tocopheroxyl radical, which is a less effective form than tocopherol. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Next, vitamin C donates electrons to the oxidized form of vitamin E (a free radical). This, in turn, reduces the tocopheroxyl radical back to tocopherol, the form of vitamin E. Hence, vitamin C essentially recycles vitamin E and extends its antioxidant life. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Enhances Iron Absorption

Iron comes in two forms found in food. One is heme iron, which is found in animal foods such as poultry, meat, and fish. The human body can easily absorb heme iron. Non-heme iron is found in plant foods such as spinach, grains, lentils, and beans. Non-heme iron is less readily absorbed because it is typically found in the ferric form. Vitamin C in the form of ascorbic acid converts the ferric iron to ferrous iron. Ferrous iron is another form of iron that can be absorbed through the intestinal wall. ^[4] Lynch, S.R., & Cook, J.D. (1980). Interaction of vitamin C and iron. Ann N Y Acad Sci. 355, 32-44. doi: 10.1111/j.1749-6632.1980.tb21325.x.

Vitamin C-rich foods are especially beneficial for vegetarians, who do not consume meat and heme iron. The majority of their diet consists of foods containing non-heme iron, which the human body does not absorb as readily. However, by consuming vitamin C-rich foods, the body allows the ascorbic acid to convert the ferric iron to ferrous iron, allowing vegetarians to absorb the iron from plant-based foods. ^[4] Lynch, S.R., & Cook, J.D. (1980). Interaction of vitamin C and iron. Ann N Y Acad Sci. 355, 32-44. doi: 10.1111/j.1749-6632.1980.tb21325.x.

Supports Heart and Eye Health

Vitamin C-rich foods lower oxidative stress and strengthen blood vessels. They can slow the aging of eye tissues because the retina and lens are highly exposed to oxygen and light, which generate free radicals. Vitamin C in the form of ascorbic acid neutralizes the reactive oxygen species before they can damage retinal cells, thereby reducing the risk of macular degeneration. It also neutralizes ROS before they can damage lens proteins, thereby helping prevent the formation of cataracts. ^[2] Kaleem, M. (n.d.). Nutrition and eye health. Johns Hopkins Medicine. , ^[3] Lim, J.C., Caballero Arredondo, M., Braakhuis, A.J., & Donaldson, P.J. (2020). Vitamin C and the lens: New insights into delaying the onset of cataract. Nutrients. 12(10), 3142. doi: 10.3390/nu12103142.

Recommended Daily Intake (RDI) of Vitamin C

This table shows the vitamin C daily requirement for several population groups. ^[6] National Institute of Health (NIH). Vitamin C fact sheet for health professionals. (n.d.) NIH , ^[8] Zelman K. (2024, January 9). The benefits of Vitamin C. WebMD.

Vitamin C has an upper limit of 2,000 mg/day. Exceeding the upper limit and excessive doses may cause digestive upset. ^[8] Zelman K. (2024, January 9). The benefits of Vitamin C. WebMD.

Signs of Vitamin C Deficiency

There are specific symptoms of vitamin C deficiency, such as fatigue, weak immunity, dry skin, bleeding gums, and slow wound healing. In severe deficiency, scurvy—a rare but serious condition—can occur. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Collagen keeps blood vessel walls strong, but without enough vitamin C, capillaries become fragile, and the gums bleed easily. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Collagen is also essential for repairing skin and connective tissue. Without Vitamin C-rich sources, it impacts the collagen synthesis, thereby slowing the healing of cuts and scrapes. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Defective collagen and keratin build-up occur in a Vitamin C-deficient human body. This creates dry skin. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Vitamin C helps synthesize carnitine, a vital component for energy metabolism. Low levels of Vitamin C cause tiredness and lowered concentration. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

If low levels of Vitamin C continue for 1 to 3 months, scurvy will likely develop. Symptoms of scurvy include bleeding gums, tooth loss, swollen joints, severe fatigue, and anemia. Extreme cases of scurvy can be fatal. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.

Vitamin C Supplements: Are They Necessary?

Vitamin C supplements are beneficial for individuals on restricted diets, smokers, or those recovering from illness. A "food first" approach is recommended. In other words, obtaining vitamin C through food sources is more ideal than vitamin C supplementation. Excess vitamin C can cause gastrointestinal (GI) distress or kidney stones. Therefore, it is essential to be aware of vitamin C's upper limits when taking vitamin C supplements. ^[1] Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211. , ^[6] National Institute of Health (NIH). Vitamin C fact sheet for health professionals. (n.d.) NIH

FAQs About Vitamin C

What are the best foods with Vitamin C?

Kiwis, guavas, papayas, mangoes, strawberries, pineapple, cantaloupe, and the Acerola cherry are fruits extremely high in vitamin C. Vegetables rich in vitamin C are bell peppers (specifically red bell peppers), broccoli, Brussels sprouts, kale, spinach, tomatoes, chili peppers, and potatoes.

How much Vitamin C do I need each day?

The vitamin C daily requirement for adult men is 90 mg, and the vitamin C daily requirement for adult women is 75 mg.

Can Vitamin C help with colds?

Yes, it can, as it supports the immune system and may help shorten the duration of colds.

Does cooking destroy Vitamin C?

Yes, vitamin C is heat-sensitive and water-soluble, so it breaks down when heated for prolonged periods and leaches into the cooking water.

Can you get too much Vitamin C?

Yes, you can. The upper limit is 2,000 mg/day.

Conclusion

Vitamin C is vital for immunity and skin health and serves as an antioxidant for the human body. A balanced diet rich in vitamin C is a better practice than taking vitamin C supplements. Consistent vitamin C intake can help the body maintain stronger health and vitality.

This article is for informational purposes only and does not substitute professional medical advice.