Vitamin C is an essential nutrient and powerful antioxidant widely recognized for its role in supporting immunity, promoting healthy skin, and its benefits on health and fitness. Fit Pros, get ready for some key facts about Vitamin C and to explore its functions, recommended intake, signs of deficiency, and the best dietary sources.
What Is Vitamin C (Ascorbic Acid)?
Vitamin C, also known as ascorbic acid, is a water-soluble essential vitamin, meaning it must be obtained from the diet since the human body cannot synthesize it (NIH, n.d.).
It plays a vital role in immune defense and tissue repair. As an antioxidant, Vitamin C supports white blood cell activity, strengthens the skin barrier, regulates inflammation, and protects tissues from oxidative damage. Furthermore, it is crucial for collagen synthesis, wound healing, and overall connective tissue health (Carr & Maggini, 2017).
Benefits of Vitamin C on Health and Fitness
Vitamin C (ascorbic acid) plays a crucial role in maintaining overall health and fitness. Here’s a breakdown of its main benefits for health and fitness:
Reduced Muscle Soreness & Faster Recovery
- It may help lessen oxidative stress and inflammation resulting from intense workouts.
- Supports quicker tissue repair and overall recovery.
Boosted Energy & Endurance
- Aids iron absorption and helps reduce fatigue, which can contribute to improved stamina and performance.
Joint & Connective Tissue Support
- Promotes collagen production to maintain joint strength and flexibility, helping reduce injury risk.
Immune Support for Active Lifestyles
- Intense training can temporarily weaken the immune system; vitamin C helps reinforce immune defenses and reduce the likelihood of colds or infections.
Top Foods High in Vitamin C
Vitamin C is essential for immunity, health, and fitness. Many fruits and vegetables provide it abundantly. The following are some of the richest sources of Vitamin C.
Fruits Rich in Vitamin C
Fruits high in Vitamin C are typically brightly colored, fresh, and slightly tart. Common examples include citrus fruits such as oranges, lemons, and grapefruits. Other excellent sources are kiwis, guavas, papayas, mangoes, strawberries, pineapples, acerola cherries, and cantaloupes (Rose-Francis, 2025).
- Citrus fruits: Their acidic environment stabilizes Vitamin C and protects the fruit’s tissues from oxidation (Kaleem, n.d.; Rose-Francis, 2025).
- Kiwis: High in ascorbic acid, they defend against oxidative stress and help maintain cellular health (Rose-Francis, 2025).
- Guavas: Their high Vitamin C levels protect against DNA and pigment damage from intense tropical sunlight (Rose-Francis, 2025).
- Mangoes and papayas: These tropical fruits produce extra antioxidants, including Vitamin C, to guard against UV radiation and oxidative stress (Rose-Francis, 2025).
- Strawberries: Vitamin C helps protect their delicate anthocyanin pigments from light and oxygen (Rose-Francis, 2025).
- Pineapples: Contain Vitamin C and enzymes like bromelain, aiding tissue repair and defense (Rose-Francis, 2025).
- Acerola cherries: Among the richest Vitamin C sources, they evolved to withstand intense sunlight (Rose-Francis, 2025).
- Cantaloupes: Work alongside beta-carotene as part of an antioxidant defense system for the fruit’s orange flesh (Rose-Francis, 2025).
Vegetables Rich in Vitamin C
Vegetables also provide excellent sources of Vitamin C, including red bell peppers, broccoli, Brussels sprouts, kale, spinach, tomatoes, chili peppers, and potatoes (Rose-Francis, 2025).
- Red bell peppers: Accumulate Vitamin C and carotenoids as they ripen, protecting their pigments and seeds from UV stress (Kaleem, n.d.; Rose-Francis, 2025).
- Broccoli: Uses Vitamin C to preserve chlorophyll and maintain cellular integrity (Kaleem, n.d.; Rose-Francis, 2025).
- Brussels sprouts: Compact buds rich in Vitamin C to resist oxidation and withstand cold (Rose-Francis, 2025).
- Kale and spinach: High antioxidant production protects against sunlight exposure (Kaleem, n.d.; Rose-Francis, 2025).
- Tomatoes: Ascorbic acid stabilizes lycopene, preventing oxidation during ripening (Rose-Francis, 2025).
- Potatoes: Provide Vitamin C that helps prevent enzymatic browning and oxidation, making them a major dietary source (Rose-Francis, 2025).
- Chili peppers: Contain high Vitamin C levels and capsaicinoids, which protect against pests and UV damage (Rose-Francis, 2025).
How to Get Enough Vitamin C Daily
Including a variety of Vitamin C-rich foods, such as fruits, vegetables, and fresh juices, can help you meet your daily needs (Zelman, 2024).
Tips for maintaining adequate intake:
- Eat foods raw whenever possible, as Vitamin C is heat-sensitive.
- Avoid overcooking and long storage times.
- Pair Vitamin C-rich foods with iron-rich meals to improve absorption.
- Incorporate smoothies and salads into your daily routine (Zelman, 2024).
Key Functions and Health Benefits of Vitamin C
Boosts Immune Function
Vitamin C enhances white blood cell (WBC) activity, including phagocytes that engulf harmful microbes, and supports T and B cell function. It helps shorten the duration of colds, regulates inflammation, and protects immune cells from damage by reactive oxygen species (ROS) (Carr & Maggini, 2017).
Supports Collagen Production
Vitamin C strengthens the skin barrier by stimulating collagen synthesis, supporting skin elasticity, wound healing, and connective tissue maintenance (Carr & Maggini, 2017).
Acts as a Powerful Antioxidant
As an antioxidant, Vitamin C protects cells from oxidative damage and aging by neutralizing ROS. It also supports brain health by protecting neurons and promoting neurotransmitter synthesis. Additionally, Vitamin C regenerates Vitamin E, extending its antioxidant activity (Carr & Maggini, 2017; NIH, n.d.).
Enhances Iron Absorption
Vitamin C converts non-heme (plant-based) iron from the ferric to the more absorbable ferrous form, improving iron uptake—particularly beneficial for vegetarians (Lynch & Cook, 1980).
Supports Heart and Eye Health
By reducing oxidative stress, Vitamin C strengthens blood vessels and protects eye tissues from free radical damage, lowering the risk of cataracts and macular degeneration (Lim et al., 2020; Kaleem, n.d.).
Recommended Daily Intake (RDI) of Vitamin C
(NIH, n.d.; Zelman, 2024)
| Group | Recommended Daily Intake |
| Adult Men | 90 mg |
| Adult Women | 75 mg |
| Smokers | +35 mg/day |
| Pregnant Women | 85 mg |
| Breastfeeding Women | 120 mg |
Upper Limit: 2,000 mg/day — exceeding this may cause digestive discomfort (Zelman, 2024).
Signs of Vitamin C Deficiency
Deficiency symptoms include fatigue, weak immunity, dry skin, bleeding gums, and delayed wound healing. Severe deficiency can lead to scurvy, characterized by bleeding gums, tooth loss, swollen joints, extreme fatigue, and anemia. In advanced cases, it may be life-threatening (Carr & Maggini, 2017).
Vitamin C deficiency also:
- Weakens blood vessel walls, causing easy bleeding.
- Slows collagen formation, delaying skin repair.
- Causes dryness and keratin buildup in the skin.
- Reduces carnitine synthesis, leading to low energy and poor concentration (Carr & Maggini, 2017).
Vitamin C Supplements – Are They Necessary?
Supplements may benefit individuals with limited diets, smokers, those recovering from illness, and those with metabolic disorders who cannot obtain adequate amounts of Vitamin C through diet and nutrition. However, a “food first” approach is recommended since whole foods provide additional nutrients and fiber. Excessive supplementation can cause gastrointestinal discomfort or kidney stones, so staying within safe limits is essential (Carr & Maggini, 2017; NIH, n.d.; Rogers et al., 2023).
Research shows mixed results for the use of Vitamin C supplementation for health and fitness (Rogers et al., 2023). For example, many athletes take high doses of vitamin C in an effort to enhance their performance. However, a review of studies conducted over the past decade reveals mixed findings regarding its effectiveness (Rogers et al., 2023).
Fourteen randomized controlled trials were analyzed, most of which combined Vitamin C with at least one other supplement, typically vitamin E. Three of these studies reported positive effects, showing reduced markers of muscle damage following intense exercise with some form of vitamin C supplementation (Rogers et al., 2023).
In contrast, the remaining eleven studies found either neutral or negative impacts on muscle damage, physical performance, perceived muscle soreness, or training adaptations. Given the inconsistent evidence and the potential for high-dose Vitamin C to hinder physiological adaptations to training, long-term supplementation at high levels is not recommended. Instead, athletes are encouraged to obtain antioxidants from a nutrient-rich diet rather than through supplements (Rogers et al., 2023).
Final Thoughts
Vitamin C is fundamental to immune health, skin vitality, collagen synthesis, and antioxidant protection. The best approach is to maintain a balanced diet rich in Vitamin C-containing foods rather than relying solely on supplements. Consistent intake supports stronger immunity, improved healing, and overall well-being.
References
Carr, A.C., & Maggini, S. (2017) Vitamin C and immune function. Nutrients. 9 (11), 1211. doi: 10.3390/nu9111211.
Kaleem, M. (n.d.). Nutrition and eye health. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/wellness-and-prevention/nutrition-and-eye-health
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.
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.
Mayo Clinic Staff. Vitamin C. (2025, Aug. 14). Mayo Clinic. https://www.mayoclinic.org/drugs-supplements-vitamin-c/art-20363932
National Institute of Health (NIH). Vitamin C fact sheet for health professionals. (n.d.) NIH. https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional
Rogers, D.R., Lawlor, D.J., & Moeller, J.L. (2023). Vitamin C Supplementation and athletic performance: A review. Curr Sports Med Rep. 22(7), 255-259. doi: 10.1249/JSR.0000000000001083.
Rose-Francis, K. (2025, May 20). 20 foods that are high in Vitamin C. Healthline. https://www.healthline.com/nutrition/vitamin-c-foods
Zelman K. (2024, January 9). The benefits of Vitamin C. WebMD. https://www.webmd.com/diet/features/the-benefits-of-vitamin-c
